Green Building Forum - Heating and cooling

Sell Your Solar output??

owlman — Thu, 09 Mar 2017 20:09:30 +0000

Anybody heard of this? I received a flyer through the post today.

http://www.sellmysolar.net/

3-way Blending Valve for Buffer Tank and Multi-Fuel Boiler

tatwalsh — Thu, 02 Jul 2015 00:59:25 +0100

Hello, everybody,
Our home was originally plumbed with an indoor Firebird Oil Fired Boiler, situated in a cupboard under our kitchen counter-top. This supplied the heat for our central heating, which is split up into 4 zones, with TRVs on all of our 31 radiators. It also heated our Domestic Hot Water via a Heat Exchanger and an 80 gallon Storage Tank (Insulated Copper Cylinder).
Now, we have installed a new Multi-Fuel Boiler in our shed along with a 2000 litre Buffer Tank, which is tee-d into the old system. (Please see the attached drawing). This new system is wonderful, we have heat all over the house with loads and loads of hot water. Our home is a Bed and Breakfast and needs a constant supply of hot water and heat most of the time.
Our old oil fired system would cost a bomb to come near the comfort the new system offers. Itâ€™s amazing! It is set up in a way that allows for the oil boiler to come on should the temperature at the top of the Buffer Tank fall below 45 degrees C. (this can be adjusted to suit our needs, but we have it set to 45 degrees C.)
Should the temperature at the top of the Buffer Tank fall below 45 degrees C. Thermostat T4, at the top of the Buffer Tank (on the drawing), opens MV1, closes MV2 and switches on the Oil Boiler (OB), thus isolating the Multi-Fuel Boiler (MFB) and Buffer Tank (BT).
The cartridge in the Laddomat (L) is 63 degrees C. and the Multi-Fuel Boiler is set at 65 degrees. With these settings the Temperature Gauge (TG1) at the top of the Buffer Tank normally reads around 70 degrees C., with the bottom Temperature Gauge (TG2) normally reading around 60 degrees C.
We have one problem, though, when we have no heating on (during warm weather) the heat in the Buffer Tank can go up to 80 degrees C. at the top and up to 70 degrees C. at the bottom. This can cause the Domestic Hot Water to become very hot and, at times, cause the water in the Storage Tank (ST) to over-heat and push hot water up the Expansion Pipe (DHW/EP). At this stage the water in the taps becomes dangerously hot and is a worry. We certainly donâ€™t want anyone getting scalded.
Thermostat T1 for the Heat Exchanger is set to 60 degrees C. and Thermostat T2 is set at 55 degrees. Thermostat T1 switches on the Heat Exchanger Circulating Pump (P1) when the temperature reaches 60 degrees in the flow pipe from the boiler. Thermostat T2 switches off P1 when the temperature at the bottom of the Storage Tank (ST) reaches 55 degrees C.
We are also afraid of children touching the radiators when they come on with 80 degree water in them. Thereâ€™s something telling me that we need to fit a mixing (blending) valve between the flow and return at the house side of the Buffer Tank. Would I be correct in saying this?
I would really appreciate any help or advice on this.
Thanks.
Tom.

Valve for Heat Sink Radiator?

ComeOnPilgrim — Sat, 04 Mar 2017 20:01:41 +0000

I have two questions about heat sink radiators that I'd be grateful for any advice on.
(1) is it possible to have a valve that only directs the circuit for a stove back boiler through the heat sink radiator when the cold return flow is above a certain temperature? (see schematic).
(2) is it even necessary to have a heat sink radiator if you can instead have a valve to circulate excess heat through the underfloor heating if there is a risk of the thermal store overheating? (see second schematic).

Unventilated Ceiling Firestop Plate for Twin Wall Flue with EZ Joists?

ComeOnPilgrim — Mon, 02 Jan 2017 21:03:15 +0000

I note it is generally a requirement to have a ventilated firestop plate both on the underside (ceiling) and topside (floor) of the floor above. The purpose is to prevent heat build up in the floor void. However, we do not have solid joists, but EZ joists, which effectively mean that any heat build up would spread across the whole of the floor void. Would this be a reason not to use ventilated firestop plates? I'd rather not use them as it provides a route for smoke to the whole of the house in the event of a fire, it would conflict with the ventilation system, and presumably noise can spread from floor to floor. Any thoughts?

Eco-heating a new build

DemonR — Thu, 02 Feb 2017 16:34:26 +0000

I wonder if any of the very well-informed people on this forum would be able to offer advice on my proposed new heating set-up? Iâ€™m shortly going to be building a new house in SW France, near the Pyrenees. Itâ€™s pretty hot in the summer, and can be quite cold in the winter â€“ down to -7C at night (although often quite warm again during the day). The house is being built with 200mm SIPs panels so will be airtight and very well insulated.

There is no gas, so I am currently planning to have underfloor heating with a heat pump as the principal heat source. The house will be built on a 1m high foundation wall, so the land in front of it will have to be built up to the threshold (thereâ€™s a hill behind) so additional excavation for a GSHP using slinkies should therefore be minimal â€“ more just a question of backfilling. Iâ€™m hoping therefore that the cost difference between a GSHP and ASHP will not be too great, and I can justify the additional cost for a GSHP, with its higher efficiency in the winter.

Weâ€™re keen to have a log fire in the large open plan living room/dining room/kitchen (16m x 6.5m) for aesthetics and as a source of radiant heat on cold nights. This would also mean that I can specify a smaller heat pump capable of dealing with minimum temperatures of, say, 0C, in the knowledge that I can bump up the heat with the wood burner when occasionally necessary. So my thinking is that we get a Waltherm Zebru 15 Kw gasification wood stove installed in the main room, which could feed a thermal store together with the heat pump. We would heavily insulate it to send as much of the heat as possible to the store rather than the room, and also zone the underfloor heating in the living room so it could be turned down or off when the wood burner was running.

In the summer, indirect coils for domestic hot water at the top of the stratified thermal store would be pre-warmed by the heat pump and topped up as necessary by an electrical emersion heater. In the winter, the wood-burner could often do this job.

Solar thermal panels seemed initially attractive as a third source of heat for the thermal store, but they seem to have rather fallen out of favour as the cost/benefit is analysed against low maintenance PV Panels, whose costs continue to fall rapidly. So if I have any solar energy input to the system, Iâ€™m imagining adding PV further down the line, the output of which could then be sold back to the grid or fed to an additional low-voltage electrical immersion heater in the thermal store.

Does all this seem sensible and logical - or am I mising anything?

Fischer night storage heaters.

gustyturbine — Tue, 17 Jan 2017 10:39:37 +0000

Hi All,

A friend of mine is looking to replace his old storage heaters with new ones.

He has had Fischer out and in my view the quote is mind boggling!!

The quote comes in at 10k for direct replacement units at 1.3kW each.

Each heater is Â£1534 before a small discount!!!

I understand that these are German and have remote stats but the price seems absurd to me.

Does anyone know about this type of heater or Future Heat UK?

I have tried discussing other systems with him but as yet to no avail.

Many thanks.

Heat Hero Boiler Stove Manifold - anyone seen this?

laikipia — Sat, 21 Jan 2017 15:08:14 +0000

http://heathero.ie

I came across this product being produced in Eire which seems to promise very impressive improvements in output and fuel use in solid fuel stoves. Too good to be true.............?

Has anyone seen this in action or is anyone clever enough to understand the physics?

All the best

John

Windhager Firewin pellet boiler owners - primary air pin query

speysider — Mon, 21 Nov 2016 17:44:26 +0000

Hi all, I was wondering if any of you out there have a Windhager Firewin pellet boiler. I have one and I'd really like to pick the brains of other owners about the life expectancy of the primary air pin - that's the domed bit in the burn pot. My boiler has been in for fifteen months and has never missed a beat. It's burned 3.3 tonnes of pellets - (only ever used Verdo), done 1200 starts and has been on for 2098 hours. My issue is that the primary air pin has been crumbling since it was six months old and has now fractured completely in half around the circumference. It is still usable thankfully as I live in the Highlands of Scotland and it was minus 5 last night! I've spoken to my installer who is baffled as to how this could have happened - he's never heard or seen anything like it. I've spoken to Windhager too and they say that it's a wear and tear part and so not covered by warranty. They wouldn't say how long they would normally expect a primary air pin to last.
I accept that things wear out but I would have thought that this was a bit soon for a boiler that cost 7 grand from a reputable Austrian company.
My question is - have any of you had to replace a primary air pin and if so - how much work had it done? If you all tell me that it was 4 tonnes of pellets then I'll hold my hands up and get my hand in my pocket. It would be really helpful for me to have real life information as it's difficult to argue my case otherwise.
Many thanks in advance

Heating season performance of a full-scale heat pipe assisted solar wall

djh — Tue, 04 Dec 2012 15:31:48 +0000

There's an interesting new paper:

http://dx.doi.org/10.1016/j.solener.2012.10.008

"Previous computer simulations and bench-scale experiments showed that the heat pipe assisted solar wall had the potential for significantly improved performance relative to conventional passive space heating systems. To further test this potential, a full-scale prototype of the heat pipe system was designed, built and installed in a classroom on the University of Louisville campus in Louisville, KY. During the spring heating season of 2010 (Januaryâ€“April), maximum daily peak thermal efficiency was 83.7% and average daily peak thermal efficiency was 61.4%. The maximum hourly average room gain achieved during the season was 163 W/m2. On days with good solar insolation, the thermal storage was heated to temperatures sufficient to provide significant energy to the classroom â€“ even during the coldest days of the season. During the longest period (4 days) of low insolation during the season, average hourly heat delivery to the room from storage remained positive, and was never less than 16.6 W/m2. During good insolation days following a period of consecutive low insolation days, thermal storage temperature was quickly restored to levels comparable to those obtained during consecutive good insolation days. Estimated heat removal factor * transmittance absorptance product FR(Ï„Î±) and heat removal factor * overall loss coefficient FRUL values for the system were comparable to those for glazed liquid active collectors."

The basic idea is a solar collector on a wall with heat pipes leading through the wall to a thermal store. Ticks a lot of boxes. The paper discusses the experiment and what factors are important or not.

Ideas for two zone heating with heat pump

nsandersen — Sun, 08 Jan 2017 20:30:24 +0000

I have:

A house with 3 small floors and a very small garden. A non-condensing/non-combi gas boiler with a hot water tank and a single radiator "heating zone". In part due to a conservatory style living room extension, it is hard to control the temperature on the middle floor with the thermostat on the ground floor.

The house is built early 2000s, so has cavity wall insulation and very basic double glazing. I have topped up the minimal loft insulation.

I would like:

Two heating zones:
Ground floor
First floor (effectively "the rest", as top floor is usually OK without additional heating).

This would also make sense as I am considering letting out the ground floor while living on the top two floors (or vice versa if I hit hard times!).

I am considering keeping the gas system, but then using an air to air heat pump for space heating on the top two floors. I have had a good experience with one of these in the past and I think, considering the layout (plus small upstairs heating requirement), that a single ceiling mounted fan unit could cover top the two floors.

I would then just have to work out a sensible way of working out a contribution towards the "downstairs" gas bill for hot water.

I could upgrade the boiler when required and any sceptic/conservative future buyers could ignore the heat pump and fall back on standard gas heating.

That is probably the simplest and cheapest. I think that would be an improvement on energy efficiency/environmental costs, but if I wanted to go slightly more green, what do people think are good options?

For example, to exploit the water tank, which I expect is less efficient with a gas boiler than a combi boiler (like a storage heater it is not only hot when I need it, so some heat is wasted and it takes adjusting etc.), I could imagine:

* Using an ASHP for DHW and delivering space heating to air (is such a split possible?)

(All bathrooms are due updating or moving, so I could add the smallest wattage electric showers also to try to run the ASHP at a more efficient temperature - and if the tank emptied of hot water, the electric showers would still cope. The existing tank immersion heater could satisfy the Legionella pasteurisation legislation.)

* Using an ASHP for DHW and wet heating, splitting into two radiator loops.

(Would pobably require upgrading 4 of the radiators to minimise water temperature.)
This would need a controller with two room thermostats - don't know if this is common for ASHP systems.

* Adding solar panels to boost hot water.

This could be done in combination with one of the other 3 options - although I guess I need a water tank with two inputs. If used with the previous option I guess the controller would get quite exotic(?).

Any comments/ideas? Thank you!

Better / worse times of day to ask ASHP for DHW?

cjard — Tue, 10 Jan 2017 18:10:38 +0000

I've the option of setting my ASHP to produce DHW using a timer, and that's nice and simple.. But ever the burning desire to make things more complicated, suppose I could intelligently control it with a raspberry pi or similar, what algorithm would make an improvement over the timer approach? For example, I could download the weather forecast and get temperature and humidity readings projected and actual, and if the day was shaping up like the forecast, call for DHW at the warmest/driest part of the day.. ? I could avoid parts of the day likely to cause the pump to go into defrost, but what would those day parts look like? High humidity? Ambient temp of around 4 degrees? I'm not sure on the variables..

And would it make an appreciable performance difference over the course of a year? Enough to recoup financial outlay on components for example..

And further, suppose my house has two electricity supplies, one of which could be Economy 7/10, and suppose I had a way of alternating which supply powered the ASHP: the normal 15p/kwh energy tariff or the 5p/25p Economy7 one - are there financial gains to be had in using Economy7 and an ASHP for DHW? I suppose there must be, logically, if one can choose to use Eco7 electricity during the operational hours and "normal" electricity at other times..

Heating pipes UNDER the floor insulation, or WITHIN it? (Under screed)

treeplanter — Sun, 01 Jan 2017 23:25:07 +0000

I have 150mm of insulation in the floor (over beam and block). I've used sheets of 50mm and 100mm, only because i bought a load of 100mm seconds. Question is - can i get the plumbers to put my hot water pipes OVER the 50mm and UNDER the 100mm, rather than have the pipes underneath it all, sitting directly on the dpm/concrete, which is what they are planning to do.

It seems daft that my lovely hot (pv heated) water would run from the tank, then go underneath all the house insulation, run on 8 meters of exterior temperature cold concrete, before coming back up into the warm house, to the shower, ...when it could sit on 50mm of insulationâ€¦?
We did a beautiful job with the insulation (we could overlap the joins etc), so i imagine there won't be much heat escaping down to prevent freezing pipes either.

Would having it within the insulation be legal, or sensible? Building regs or any other restriction?
We have used Celotex and Retocel insulation boards.

alternative to expensive steel pipe for use in solar thermal

mightyworthit — Wed, 26 Mar 2014 10:17:27 +0000

Hi,
Just wondering whether any forum members had an opinion on using 'EPDM SAEJ20R3 Flexible Rubber Car Heater Radiator Coolant Hose ' on my solar thermal system? (see link below) It is a drainback system so operates at atmospheric pressure . This pipe has high operating temps(125degs) and is resistant to antifreeze. It is plyable and is only Â£50 or so for 40m!!

I have come away 3m from the cylinder in copper I would imagine that I can adapt from copper to the epdm hose using good quiality jubilee clips or similar.

There are fixings available for this stuff but simple to make using builderd band. I can insulate using a larger diameter standard insulation.

What do you think??

I have added a link to EPDM and silicone. The silicone radiator hose is Â£250 for 40 metres. Advantages?

http://www.ebay.co.uk/itm/EPDM-SAEJ20R3-Flexible-Rubber-Car-Heater-Radiator-Coolant-Hose-Engine-Water-Pipe-/200982593122?pt=UK_Car_Parts_Vehicles_Automobila_ET&var=&hash=item2ecb7efe62

or this

http://www.ebay.co.uk/itm/Silicone-Heater-Radiator-Hose-Coolant-Car-Engine-Pipe-Silicon-Rubber-New-/290841193823?pt=UK_DIY_Materials_Plumbing_MJ&var=&hash=item43b77c6d5f

UFH on existing concrete floor?

zak99 — Wed, 28 Dec 2016 19:36:21 +0000

Hi all,

We live in a dated and rather tired detached brick and block cavity wall bungalow on a concrete raft, I guess late 70's early 80' build. Its semi rural so pretty exposed to wind. Heating is an old Worcester Danesmoor oil fired boiler, it works well but is rather noisy. Gas supply is not in the village apart from bottles or tanks. Also we use a wood burner.

We are hoping to do quite a lot of work here, (roof repitch to gain loft rooms, possibly external cladding, new windows)

My question - is UFH feasible given the concrete floor, or should I stick with radiators. I think the screed is around 50 to 70mm thick (from when I did some plumbing repair years ago). I dont know if there is any insulation in the floor but i doubt it as its a pretty cold place.

I heard that electric UFH is thin but expensive to run.
How thin could water UFH be so that i could possibly get some insulation below as well.

Would i need to break out the screed, or go on top, ceilings are reasonable heights.

Thanks for any help

Rgds

Heating Heat Store with System Boiler Directly

ComeOnPilgrim — Wed, 14 Dec 2016 09:16:24 +0000

Sorry, another query. We are planning on using a heat store with a gas system boiler to top it up. The boiler manufacturer has said that we should use a coil to heat the heat store, but the reasons were not very clear, i.e.:
- it stops the boiler water mixing with the domestic hot water (but the domestic hot water is heated indirectly using a coil).
- that's the way they usually do it.
By contrast, the heat store company shows a boiler connected directly (see attached). Can somebody explain why one might need to use a coil?

Smoke Nuisance from a wood Burner

cleanairforall2 — Mon, 26 Sep 2016 15:20:53 +0100

Our neighbour installed a wood burning stove last year, since then we have suffered smoke pollution all through (2015-2016) autumn, winter and spring (5 or 6 times a week+) 80+ incidents (many witnessed by a Council EHO) of pollution coming into our home and garden (not a smoke control area). Whilst wood burners are acceptable in the correct environment i.e. rural areas where the particulates can be safely dispersed with no significant risk to others health they should be avoided in built up urban environments.

We've kept diary of events, purchased an air monitor and had EH officers witness the nuisance (whilst our neighbour continued to pollute) but to no avail. On investigation we found DEFRAâ€™s own advices state wood smoke represents a serious health risk and is also potentially carcinogenic <10um and <2.5um particulates. However, just as Mikeee5 found involving the local Councils Environmental Health and Building Control, etc proves difficult if not impossible to get the EHO's or Building Control to accept there is a problem or take any action to abate it (is it a cost issue?).

We thought we could get the nuisance stopped quickly after contacting our local councils EH Officers, Building Control etc to no avail the officers rely on the small print of the legislation and legal definitions regarding minimums so that in spite of many incidents of smoke entering our house which were witnessed the Councils EHO's no action is taken.As a Chartered Engineer in my own field of engineering I expect officers with legal responsibilities to behave in a fair, honest and even handed way. O how wrong could I be? According to the EH Officers the smell of smoke in our home is only a "Statutory Nuisance" if they deem it to be, based only on their opinion and the DEFRA guidance regarding frequency, duration, ect (F.I.D.O.L.) is, it seems, ignored. A law unto themselves?

We have tried to engage our neighbour on a number of occasions but theyâ€™ve confirmed they do not intend to change their behaviour and we expect the nuisance to re-start sometime very soon, at which time we will have no option left to us but go to court as a private nuisance. Your support and helpful comments will be welcome (not just close doors and windows which was the initial advice by the EHO's).

Infra red heating - floor and ceiling

Miked2714 — Wed, 05 Oct 2016 09:02:25 +0100

I haven't seen any discussion for a while, just wondering if anyone has experience with electric far-infrared heating mats either in floor or maybe even ceiling. Seems too good to be true. I'm looking for a product to provide supplemental heating for both large and small rooms, where it's awkward to get an even heat from the main wet central heating.

Ideal temperature for bedrooms

tony — Sun, 04 Dec 2016 19:34:06 +0000

What is the ideal design temperature for bedrooms?

Height of header tank for vented thermal store?

ComeOnPilgrim — Sun, 04 Dec 2016 10:30:02 +0000

We'd like to use a vented thermal store. The store is 2250 mm high, but the head height is only about 2300. Is this enough space for a header tank? If not, are there any other solutions?

Boiler stove gravity circuit advice

PFF — Sun, 04 Dec 2016 20:08:21 +0000

Hi

First post to the forum after reading avidly for the last few months!

We're going to install a wood burning boiler stove (arriving in a couple of weeks) to provide DHW and part of our heating needs. We've had great difficulties in getting a heating engineer to do the installation, or even advise us, so looks as though we may doing it ourselves with our very good builder (he's plumbed in boiler stoves before but by his own admission is no expert).

We'd like to keep things as simple as possible so have tried to design a basic gravity fed system as shown in the attached schematic. The system is basically:

-WBS with 20,000BTU (5.8kW) boiler on ground floor
-Vented thermal store cylinder (just used for DHW) of around 170L on 1st floor almost directly above WBS (3m rise). This is directly fed from stove on 28mm pipe. Want to use a thermal store as opposed to a standard cylinder for mains pressure hot water via heat exchanger - but am open to advice as to it's suitability.
-Two heat leak radiators in series with 22mm piping - one (2.5kW) on 1st floor landing about 6m away from cylinder (we can run pipes to it in a ground floor extension loft space so they can gradually rise). The pipe would then drop to a small (0.5kw) radiator in a utility room on the ground floor before returning to stove - again possible to keep the pipework descending all the way back to the stove.
-A possible pumped radiator circuit to 1 or 2 other small radiators on 1st floor - this would be in case of the system overheating but also would be good to have option to turn pump on manually (see below).

I just have a few questions about the system:

1. Will it work as a gravity circuit? My thoughts are making the pipework to the cylinder 28mm will take priority over the 22mm pipework to the heat leak radiators so the cylinder will heat first. As the cylinder gets hotter more hot flow will head to the heat leak radiator loop on the narrower pipe work. We want to avoid using lots of pipe stats and motorised valves etc to direct the flow around - mainly for simplicity and that we get numerous power cuts here so be good to have a circuit that took care of itself.

2. Can we use a single F&E tank for the whole circuit if we use a direct cylinder (i'm thinking something like the Gledhill Torrent ECO OV)?

3. Where should the F&E tank feed the system? Most schematics just show it dropping in anywhere on the return pipe. One stove manafacturer told us we should feed the system at it's lowest point with a dog-leg in the pipe.

4. Where shoud the pipe stats go for the pumped circuit? Some schematics show them on the flow from the stove and some on the return. Makes sense to me to be on the return as if the water is hot when returning to the stove then really need to be dissipating more heat.

5. Can the pumped circuit be manually switched as well as controlled with pipe stats? Be good to have that option as may feed a bathroom radiator on the pumped circuit.

6. Any details i've missed on my layout? I've seen non-return valves shown on some schematics but not sure if these are necessary on a gravity circuit. Similarly load valves and neutralisers - again not sure if they have any benefit or work on a gravity circuit?

Would really appreciate some advice on this one as hope to be plumbing this in next month.

Thanks in advance

supplementing heating with air with UFH?

jamesheath — Tue, 29 Nov 2016 22:09:12 +0000

Hi all,

I'm in the throws of building a non-certified, but (hopefully) compliant, passive house, and am struggling with conflicting advice over the heating.

The house is big - 450m2 TFA, and three storeys.
We have an insulated slab, and then a timber frame sitting on top of it.

The main heating is by a combination of towel rads in all bathrooms, and wet batteries on the MVHR air supply.
These are supplied from a 1500L thermal store, which itself is fed by a fairly large solar thermal array, a gas boiler, and a wood burning stove (I know I know - crazy in a passive house, but we wanted one!).

This may well all work wonderfully, but there are two concerns...

1/ It is possible that more heat will be required on really cold days - PHPP says we can't heat with hot air alone (we're about 1kw short) that may be met by the towel rads, but the heat from them is surely mostly heating the air anyway? We could just light the wood burner, but I may not be around to do that, and it then wouldn't happen.

2/ It seems possible that if the house is warm enough on average, there may be stratification of the temperature over 3 floors. The lowest floor has a one bed flat for my Dad - and the living room there needs to be warm. The next floor up is our living area - where we want it warmest. the top floor has the bedrooms, where if anything, we'd be happy for it to be a degree or so cooler. (and yes, on typing this out, I realise we probably ought to have designed it the other way up).

Our ideal plan would be to build the house, spending just a little extra on allowing for retrofitting of stuff to fix these issues If they arise, spending more to combat specific issues after living in it for a winter, rather than over spending now.

Luckily, one step in that direction is relatively easy to do - there's a wet heating circuit in for the towel rails, so we can fairly cheaply leave some points of that behind plasterboard to allow retrofitting of small rads. It just so happens that nearly all of these can actually go on the other side of a wall from the towel rads, or where the heating pipes were running anyway.

The other option in addition to that, that I'm wrestling with now, is whether to put UFH circuits in to the insulated slab. For the most part the lowest floor will have the slab polished as the floor finish.
To minimise the spend on something that may never be used, I would likely lay the pipes and temp sensors only (I would pressure test though). This would probably cost 300 - 400 quid, and a couple of days of my time wrestling with PEX pipe.
I'd then add the manifold, mixing valve, controls etc if needed.

If needed this would dribble some background heat in to the bottom of the house, and the hot air would then do the rest and get the room temps right.
I'd likely control the temp of the slab to a few degrees above the desired ambient temp, and let the hot air do the rest.

Is the UFH:
a) a bad idea
b) a waste of cash
c) riddled with difficulties

-if- people out there think the UFH has legs (it would be nice to have a slab just slightly warmer than the room I think?), what kit is out there to control the slab to a given temperature? I was going to just put some DS18B20 one wire temp sensors in the slab & roll my own control, but that might be dumb if what I need is out there.
(I'm comfortable with code & soldering irons!)

I'm also really keen to hear from others living in passive houses with unheated insulated slabs - do they feel cold? and anyone in a large house heated predominantly with air - does the top get other than the bottom?

Sorry that was so long winded!!

Thanks,

James
Hove

Air source used along side combi boiler

barnconverter — Fri, 25 Nov 2016 10:37:27 +0000

Hi all, I have got a gas combi boiler running hot water and central heating upstairs in my property. I am just wondering if it would be possible to run underfloor heating downstairs using a small air source heat pump say 3KW as a stand alone system. Would we require a water cylinder as we don't have much room for one? Any comments much appreciated. Thanks

Bought A House With ASHP

escapologist — Mon, 21 Nov 2016 19:15:50 +0000

I've recently bought a house in Wales that has a 16kw ASHP installed. Its an old farmhouse but rebuilt in the 70s after it burnt down, so not granite walls. Anyway, previous owners installed this along with oversized radiators throughout the house except for a new "sun" room that has UFH and a separate pump. In the airing cupboard is a big modern water tank to go with the system.

They were told to keep the hot water on at all times, so they've passed that info to me. There is an additional immersion heater in the tank that can be run from a timer. House does get nice and warm, so no issue with that but the problem seems to be that the electricity consumption is very high - 17.7 Kwh last year and I clocked 90kwh in just over a day, although I will admit to having had the heating on nearly the whole time as I was seeing how it went.

I had arranged a service and the engineer, different from the company that installed as they are England someplace, had a good hunt around. ASHP & tank installed by different people apparently and he discovered that the temp sensor for the hot water/ASHP was not installed correctly (loose + electrical tape?!) He suggested that the sensor would be unlikely to record the correct temp and that the unit might not turn off when max temp achieved. This sounds likely I must admit, so hopefully he is obtaining the correct sensor etc.

What I'm looking to find out is how best to run the heating in the house. Currently working away and using at weekends.

Should the hot water be on at all times?
Should I use the immersion to raise the temp sometimes to ensure ASHP not running hot water? I know I have to raise it to 60 to kill bugs every now/again.

Seeing as how I already have this system in the house, what can I do to make its operation more efficient? I was thinking of installing some PVs and have them power the immersion (when enough oomph). Would also look to have battery maybe for non-generating hours. Ideally I would like to generate my own electric as much as possible though would probably struggle to get enough to feed the current ASHP's thirst...

Any other suggestions welcome!

Heating a Thermal Store

Michael1 — Fri, 04 Nov 2016 21:24:53 +0000

Hi all, been looking at a Thermal Store 500ltrs and it has the ability to be heated by Solar Panel, Photo Voltaic and Woodburner. I will be in a position the install all three but is it the best way to go. I will go with the Woodburner as I have my own supply of wood.
I will be insulating as much as poss to floors ceilings and exterior walls.
Michael.

Our old mate Damon Hart-Davis

SteamyTea — Sat, 19 Nov 2016 13:21:21 +0000

Some of the older members may remember that Damon was working and a self setting/programmable room stat.

He has asked me to post up a link to the website.

Hopefully it is not too commercial and others find the project useful.

https://myradbot.com/

New Heating System Advice

Herodotus — Sun, 06 Nov 2016 09:11:43 +0000

Hi All,

Looking for some advice on how best to approach a new heating system - primarily for DHW but perhaps later for SH via UFH.

We live in a small single storey house with a flat roof in the mountains in southern Spain. We are currently working on getting it properly insulated (from the outside!) but the bureaucracy involved means it's probably going to take a while. We currently have 3 woodburning stoves - two small freestanding ones and a larger glass-fronted one built into the old chimney in the living room. For DHW we have a decrepit on-demand gas boiler connected to a cylinder outside.

Our DHW demands are fairly limited. Normally we'd have between 2 and 4 people living in the house, but we're all grubby hippies and we probably shower a maximum of 2.5 times a week on average, and we probably don't use more than 30l of water when we do - so that's 300l of shower water a week - of which not all will be from the hot water system. The rest is washing up/domestic cleaning, so I'd guess we're not normally using more than 100l of DHW / day at the absolute maximum - and usually less.

The DHW system needs changing urgently. Our water comes from our own springs, and we don't have a huge head on it - currently only a few metres - might end up being more soon if we can get another tank commissioned a bit higher up - but pressure isn't great. We're having loads of problems with insufficient pressure causing the boiler to cut in and out when having a shower + the boiler is old and not very good anyway. We have a lot of free wood available and an aversion both to on-demand gas boilers - which I've never liked - and using fossil fuels for heating generally.

We'd like to move to heating our water with wood + PV electric (we have a 3.75k solar array whose output we are rarely using to the max) + possibly some sort of simple solar collector. For the time being we're going to try and continue to do space heating using the wood burners but it's possible that at some point in the future we'd like to have the option to do something with UFH if we have the time/money to redo all the floors :-/

The obvious simple solution in a UK property would be a vented DHW cylinder with two coils, one from a wood boiler and one from the solar (with the option to add a buffer for UFH later). The problem with this is that, living in a single storey building with a flat roof, the venting/expansion requirement is tricky to do. I don't want to have to have a pump just to get adequate DHW pressure. Is there a way round this that I'm missing?

From a safety perspective, I'm pretty uncomfortable about a sealed system with a solid fuel boiler. Even with pressure relief valves and maybe a heat-dump towel rail or somesuch, the prospect of having a potential bomb that could flatten my house if I overstoke the boiler makes me twitchy. Also, pressurised cylinders seem like an important potential point of failure even in "normal usage" - I believe in the UK they need to be inspected annually for this reason? Am I being unduly paranoid about this? Is there a way to use a sealed system with a solid fuel stove safely?

That leaves me with some sort of thermal store option - dumping the heat from boiler + solar + electric into a big tank of water and then extracting it into DHW via an internal coil/internal tank/external PHX. In the future we could potentially use the store water to run UFH as well. On paper this looks like the most suitable option for us, but it's also going to be expensive + I'm worried that for the quantity of DHW we need it's pretty wasteful heating a big thermal store. I'm also lost on the whole internal coil vs external PHX thing - I'm obviously keen to maintain as much stratification as possible so that we can get sensible temp DHW with a minimum size store, but I can't work out which system is better for that. PHXs can return cool water to the bottom of the tank, but only if the hot water demand is enough to coil the primary circuit water significantly; coils give you a certain amount of stored hot water + they're simpler + their impact on the cylinder water isn't dependent on speed of DHW demand, but I'm guessing that even the best designed coil is going to destratify the cylinder more than a PHX system operating in ideal conditions...

Other points to note (in no particular order):

* We're at 1200m altitude and it does freeze here occasionally - solar collector probably needs to be indirect with glycol I guess
* We get a pretty decent amount of sun most of the year - our small DHW water needs can probably be delivered from solar almost all of the time if it's done right

Any thoughts/pointers gratefully received!

Cheers,

Noisy Hot Water tank when heating is on

Dominic Cooney — Fri, 04 Nov 2016 19:03:17 +0000

Haven't posted on here for a while...
but have been busy as we've sold up and bought a smallholding 2 years ago. There's so so much that could be discussed regarding the new place but -
the problem that's bugging me at the moment is the noise of running water from the hot water tank when the central heating is on.
We recently had the system drained down in order to have a new immersion element fitted (it was completely shot and was tripping the electric), and a leak fixed on a radiator pipe on the ground floor.
The immersion now works fine and provides hot water when the oil boiler is not in use, so there was no problem for the first few weeks
When I came to put the heating on now that the weather has gotten a bit cooler (just for an hour morning and evening to take the chill off), there is a lot of noise from the hot water tank, gurgling and such but mainly sounds like running water. Only when the pump is running. Pump seems to be working, can get heat to all radiators.

When the heating (timed) goes off the noise stops.

It didn't make this much noise before all this.
I had been using the oil boiler for hot water only for a while until I got the plumber in to do the immersion, and it wasn't making all this noise.

Bog standard Hot Water tank is on the first floor, indirect heating coil (I'm guessing) nothing fancy. woefully under-insulated of course, but that's another story for another day...

Been up in the loft and there doesn't seem to be any sign of boiling or bubbling in the expansion tank.

Any thoughts or suggestions?
I could probably bleed all the radiators again to be certain, but I can't help thinking it is something else, maybe an airlock or something? The system is quite old and has been extended/added to over the years.

Triple Wall Chimney Question

ComeOnPilgrim — Mon, 31 Oct 2016 18:10:26 +0000

We have a new build which we hope to be very airtight. I was quite excited by a triple wall chimney which offered to suck the air needed for the stove through the same chimney as the smoke would go through. However, the company have just quoted me Â£4K for installation, or Â£2K for the materials. This seems a bit pricey, so I am reconsidering it. I have a couple of questions:
1. What's the real benefit of a triple wall chimney? Could I not just get a double wall chimney and have a different pipe bring the air to the stove?
2. I was previously thinking that the chimney would go through the ceilings and the roof, but this is quite problematic as the joists do not line up on the 1st and 2nd floors, and then there are the rafters on the roof. Could I not just go through the external wall and up the outside of the building?

Infrared radiant bathroom heaters

smudger — Fri, 29 Aug 2014 15:04:45 +0100

I was about to order some Rointe Towel rails for our bathrooms (running off economy 10) to combat chill and counter mould on walls (solid block, north facing). If the green deal is ever resurrected we will externally insulate but in meantime we need to do something this winter.

An older post mentioned infrared radiant heaters as an alternative (in ceiling, not what we want to do). I've come across 'mirror' types that go on the wall but struggling to differentiate between them and they are also more expensive than the rointes.

Will they do the job I want and any seen any in the flesh to be able to recommend any?
Ecolec, greenage, ecolec, agadon and stove centre have been thrown up by g**gle.

thx

Hot bedroom with twinwall flue,how to cool...

Julesbarn — Thu, 27 Oct 2016 20:57:57 +0100

Hi again,

After remedial first floor ts insulating,(with great results),one of the bedrooms is still getting too hot..and of course it's the one with the flue passing through. It happens when the stove is running; not when the ts is charged. The small landing remains cooler. The flue is boxed in and vented top and bottom,with 60mm clearance as it should be.

I thought a clever fan arrangement might work to redistribute the unwanted extra heat, and I had a mild eureka moment!

We have a flue thermostat which starts the back boiler circuit pump when the flue reaches a certain temperature. If i wire up a little fan to start when the pump kicks in, (and of course stop when the pump stops; when the flue has cooled enough),then i can have heat extraction from the boxed-in void when appropriate.

Of course,i must maintain my 60mm clearance between flue and combustibles, so the fan cant be within the boxed-in void. Perhaps a length of 50mm diameter stainless flexi pipe (i happen to have some lying around) could take the heat from the void, with the fan located on the cieling below,in the sitting room, above the wood stove, but 60mm+ from the flue. Not only will this put the unwanted extra bedroom heat where i want it, but help move and mix the radiant heat from the stove across the gf sitting room and open plan kitchen/dining area.(a bit like those stove-top heat driven fans).

Please tell me this is a good idea..or why it may not be! (maybe it's been done before). I used to sometimes have the most wonderful inventive ideas whilst drinking too many beers of an evening in my workshop...until the morning,when i saw my sketches and scribblings from the night before,and felt a bit silly! I don't do that any more. So,again,i hope I'm not missing something.

Any thoughts welcome

Thanks,

Jules

Thermal store..too hot upstairs!

Julesbarn — Sun, 23 Oct 2016 15:13:03 +0100

Hello everyone,
I've just joined this brilliant forum,and firstly I'm seeking help with a dilemma in my recently completed barn conversion.

I did all the work myself,and we love the results,but I was probably given some not so good advice along the way.we have a 390 l thermal store located on the small,first floor (rooms I'm the roof,so low volume as well as floor area),which is served by a 14kw wood boiler stove in the sitting room near the stairs. (Solar thermal yet to be fitted; coil waiting at the bottom of the store). The system seems to work really well; with plate heat exchanger for dhw,ground floor ufh,and a small radiator circuit on first floor which we will probably never use : (

Our problem is that it gets too hot upstairs for our two daughters bedrooms, sometimes even when the stove is not lit,but the store is hot.(me and partner,have gf bedroom which is cool if we want). As a result,the girls insist on opening the roof windows to cool their rooms,thus letting a lot of precious heat out and noticeably cooling down the ground floor. It really frustrates me; i meticulously fitted a lot of insulation in the roof, and even used a perlite/lime backing plaster on the thick cob walls for that extra bit of warmth (perhaps?!?).

My thoughts on how i can improve the situation are....

1. Add loads more insulation around the thermal store itself - which I'm in the process of doing,

2. Insulate the ts cupboard doors- done that, with 25mm celotex,

3. Add more insulation to the ts cupboard itself,

4. Tell the girls to shut their bedroom doors if their windows are open - they don't always, so I'm often trotting up the stairs to check.. A real hassle!

5. Fit door closers on their bedroom doors - "dad, you're getting a bit anal about all this heat loss stuff !" ,

6. Somehow fitting a fan somewhere clever to either send heat from the ts cupboard,or ff in general,downstairs to equalise the temperature of the barn.

I can't isolate the two floors,the landing is tiny so a door at the top of the stairs wouldn't work,or comply with regs, and the bottom of the(kinda) spiral stairs are open to the sitting room and a very beautiful feature,and i aint moving the store downstairs...there's nowhere it can sensibly go (and the thought of re-routing all the plumbing..!)

Soo, I'd love to know your thoughts; if any or which of my ideas,would help remedy the situation. Of course,it's not all the thermal store's fault,bless it...the woody puts out 5 kw max to space (officially),and,as i said, it's located near the stairs. Oh,and by the way,all first floor voids are well insulated,with super good underlay n carrpet above!

Many thanks, (as i have gone on a bit)

Jules

Solar collector for MVHR pre-heating

EasyBuilder — Thu, 22 Sep 2016 22:59:55 +0100

Except during a heatwave my MVHR takes its input from the loft at the top of a south facing roof slope. Even with an efficient heat exchanger there is benefit, especially because I've added a thermostat to turn on boost and summer bypass when the incoming air is over 22Â°. With this it can heat the house on sunny days from March onwards. However there's less benefit in winter, not just through less sunshine, but also because the roof loses a lot of heat at night and is slow to warm up. Would it be better to take the fresh air from a solar collector on the south wall mounted below the eaves? I've seen them made from twin wall polycarbonate, or from perforated metal, but don't know which would be best, or what the optimum size would be. I'd appreciate tips from folk with experience of these things.

Insulating wooden panel doors

Julesbarn — Tue, 25 Oct 2016 12:10:17 +0100

Hi. I am already getting a fair amount of condensation on my two external panel doors on chilly mornings (on the panels themselves). Is there any harm in insulating the panels,if the edges are sealed to the door?
The doors are chunky douglas fir,the panels being 22mm thick. They are stable doors,top part 2g argon 16mm gap,and hardly any condensation yet,but the bottom panels have been pretty wet some mornings. Worst affected is east facing, other west facing and not so bad for some reason.

I could make some doug fir panels to fix over existing recessed panels giving a 15mm gap to fill with....
Bubble foil,carpet underlay,celotex cut down to 15(horrible job),something reflective, or just a gap vented/unvented??

Is it worth it? Any ideas welcome

Thanks,

Jules

Heating P&ID. Please can someone check my proposal. Stove, GSHP, UFH.

geoheated — Tue, 25 Oct 2016 13:22:25 +0100

Hi All,

Would appreciate any feedback on my layout. It took some months for me to get this down on paper.
Its part of my renovation of the entire house.

I have no experience with stoves but have spoken to a few people and read alot about the requirements.

I have purchased a good used 6kW GSHP. Heat losses for the house are around 5kW peak.

I hope to extend the house in a few years, so ground loop and DHW tank are sized to allow for an 8kW GSHP and 2 bath's 1 Shower.

Hope it makes sense....

Thanks

Heating solution for straw bale hall - Radiators or IR?

Sandbank — Sat, 22 Oct 2016 15:25:01 +0100

I need advice for affordable options to retrofit permanent heating in a new strawbale hall, 80m2 with a high sloping ceiling. Ceiling, floor and upper walls lined with sheep's wool, covered with plasterboard. Rationel windows and entry door. (We did not have enough money to put the heating in at time of construction, otherwise UFH would have been desirable). The hall is mainly used evenings for dining, also in the day for groups eg for yoga/meditation - so noise is a factor, also ease of use as its hired by outside groups. To date, we use 4 x 3kw oil-filled radiators, to establish the requirements. Left overnight they heat the room sufficiently for a weekend.
One option (cheapest?) is to hardwire in electric radiators - there are limited fixing points on the walls, but it is possible. Maybe in conjunction with a heat curtain at the entrance door.
Another option is Infra-red from the ceiling? Would this be more efficient in the long term? The hall is generally clear of furniture etc.
There is an array of 64 solar panels on the roof, which feed into our general supply for other buildings. See www.kenchhill.co.uk

Infrared heater staring at wall

gyrogear — Sat, 08 Oct 2016 00:49:26 +0100

Since I retired my electric floors, our large lounge can be pretty cool of a winter morning (18.7Â°C on 15 November last year, which was too cold even for me...). This is no doubt due to the fact that my (purposely undersized) 7.5 kW woodstove does not last through the night... One solution is to set the alarm for 5:30, do a quick burn and go back to bed - not very "lifestyle-friendly"...

I am therefore considering adding two low-cost infrared heaters -- dual 600/1200 watt (tubes). Since these are not very aesthetic, I want to mount them on the back side of the tie beam that connects the two roof trusses (we have a cathedral ceiling) -- the tie beam is parallel to the ridge purlin, and about 2.5 meters below it.

The heaters would then be well above floor level, off our general trafficable route, and out of sight. They would be pointed at a partition wall, 4m x 4m and 1.5 meters distant, which is the frontage to our northern rooms (bathrooms, toilets, box-room, loftspace). The partion wall is hollow-brick with plaster over. The backside of the upper half (to loft space) is insulated with 30mm XPS.

The idea is to use the IR to warm the partition wall, turning it into a sort of "storage radiator". This would collaborate with our ceiling fan... For just a couple of hours - once the sun gets going (around 10-ish) we are generally OK...

If the system works, I would get the electrician to install some sort of timer control.

Would be grateful for opinions, to see to what extent I am "off the wall".

gg

Ariston NUOS

smudger — Fri, 30 Sep 2016 21:07:38 +0100

Anyone seen, used or opinions on these?

http://www.aristonthermo.com/en/Brand/water_heating

http://www.bse3d.com/wp-content/uploads/2014/10/Ariston-Heathrow-Perfectionists-Cafe-NUOS.pdf

I'm looking for efficient water heating system with a bit more flexibility than off peak cylinder/immersion (we also have 'excess pv' to benefit from).

Any alternative solutions to look at?

small Backboiler heat sink

Terry Hudson — Sat, 17 Sep 2016 15:25:27 +0100

Im plumbing in a simple primary radiator circuit off a wood burner back boiler that only puts out 3 Kw
I will use a pump as I want a rad in the cellar as well as the ground floor.
I only need a tiny heat sink radiator of a half a KW ? (in case of power failure)
How much heat is lost on a 6 meter 28 ml copper pipe to the loft vent?
does the heat sink radiator have to be the first radiator?
can it be in the cellar on the return run?
It seems like I am asking the impossible.
Any thoughts would be appreciated.
I am likely going to want to use the fire, without heating anywhere upstairs is my problem.
Thanks

Crazy idea - smoke alarm inside MVHR plenum?

Swarm — Mon, 05 Sep 2016 00:04:17 +0100

I'm thinking of adding more smoke alarms, to bedrooms, a cupboard with server in etc. Then I thought, what about adding one inside the extract plenum for my MVHR. Then if by some remote case of a fire starting in a bathroom, the smoke would quite quickly find it's way into the plenum and trigger the alarm.

Which will then alarm the others and shut down power to the MVHR.

Rehau Helix Probe alternative

jonc_uk — Mon, 05 Sep 2016 16:37:51 +0100

Hi All,

I have an extension which has a basement and intended to install about 20 Rehau helix probes underneath it to create an inter-seasonal heat store.

The basement has been dug, and formwork is scheduled for the end of the week. Today I have found out that Rehau have stopped supplying them!

Does anyone know of an alternative? This is the one opportunity I have for the heat store. I did a lot of research about methods of storing the heat and these seemed like the best solution. The floor area is about 220sqm.

Thanks for any help.

Jonathan

Calling Kinetic MVHR users - remote boost control upgrade

Swarm — Sun, 04 Sep 2016 19:28:59 +0100

I've experienced issues with the humidistat in my Kinetic where it will cycle between low mode and boost at night. So I've just turned off the humidistat.

This is not ideal for showers etc. so I'm wondering about using Z-wave home automation (which I already use and am familiar with) and humidity sensors in each room, or possibly little switches in bathrooms for manual control. Or both!

I'm posting in the hope that someone more proficient in electrical setup can assist a little bit. I can do all the home automation side but don't quite get the wiring of how the following will interact:

Fibaro switch manual: http://manuals.fibaro.com/content/manuals/en/FGS-222/FGS-222-EN-A-v1.01.pdf

From the Kinetic manual:

"The unit can be switched to boost by a variety of methods:
ï® Applying 240 V to the LS input .
ï® Switching across 1 of 5 pairs of switch terminals.
ï® Applying between 0 and 10 V as a proportional input to two input terminals. "

Page 23 / 24 of the Kinetic manual is relevant: http://www.vent-axia.com/files/pdf-downloads/439817Q_4.pdf

Any help much appreciated, or I will have to try Vent Axia support and hope they're helpful. :)

Rayburn and smokey chimney

Quercus-Jim — Fri, 02 Sep 2016 11:14:38 +0100

Hello all,
Wondered if anyone could help shed some light on why my newly installed (used) Rayburn Royal mf seems to smoke excessively (from the flue top). It's a cooker only installed with a 6" twin wall flue which rises to about 4m above a flat roof. The thing that's baffling me is that I'm burning kiln dried hardwoods (which burn very cleanly in our Rojek boiler and produce no smoke once heated up) but with the spin wheel open to any degree and the flue damper open it chucks out a dark brown smoke which doesn't ease up even when everything has warmed up. I've tried all combinations of spin wheel open/shut and various damper positions but nothing calms it down. It has a very good draw and doesn't takes minutes to get going like a furnace. The only way I can stop it smoking is to close the spin wheel fully and almost fully shut the damper then it produces barely a whisp of smoke. Thing is, I don't like shutting it down within a few minutes of lighting as it's obviously going to soot up the appliance and flue. This seems almost backwards to me, as ime a woodburner would smoke more if you bank it down soon after lighting. Have checked the inside of firebox and under hot plate and nothing wrong, flue was new, wood around 18% mc. Surely it should be burning very cleanly given the above? Can too much draw make dry wood smoke excessively? I ain't never seen it with 2 woodburners and a boiler but this setup seems special. Any ideas gratefully received! Thanks Jim

MVHR Duct Condensation trap or not?

Phil.Chaddah-Duke — Tue, 09 Aug 2016 09:14:25 +0100

Hi guys, currently extending our MVHR system to new basement incl moving unit. I see references on at least one site if needing a trap at bottom of vertical pipework carrying stale air to outside to stop any condensation running into unit. We are using 160mm round steel ducting which is inside heated envelope along with unit itself. The unit has a drain but I assume that deals with water from the heat exchanger.

I can see the theory that as the warmer air meets colder pipe as it exits the building but don't find any such drain product for steel ducting and also how would such a trap work as it would need to he airtight? Any thoughts/experiences appreciated?

running a DC fan off of a battery charger ?

gyrogear — Fri, 26 Aug 2016 00:11:59 +0100

I have two battery chargers - one is "automatic" (to avoid over-charging): per booklet, the absorbed power = 90W.
Booklet also says : "do not use this device for anything other than charging a battery". fair enough.

My second charger is old and I have lost the booklet, but it works!
It charges at 3.5 A, off 240V AC.
I have used it to run an automobile fan - 90 W, 12 V, it runs at around half-speed, which is OK for my application.
I am (1) curious to calculate the absorbed power and (2) curious to know whether I should not use it in this application ?

(I don't want any fires !).

Thanks for any assistance !

gg

MVHR filters and traffic pollution

Swarm — Thu, 25 Aug 2016 17:54:19 +0100

I've only had my MVHR running for a few months and noticed that one of the filters is very dark grey, rather than the white it was. The MVHR vents are about 10m up on the outside of the house and about 5m horizontally from a road that's not that busy. Although we do have a bus stop outside... :(

Has anyone else experienced traffic pollution on their filters? It makes me wonder what is getting past the filters...

Also, is it normal for a lot of water to be in the heat exchanger, I pulled it out to check it over and got a shock when water started spilling out!

Lastly, as mentioned in another topic, I'm getting quite a lot of fruit flies and the odd fly + month loitering in the unit too. Just concerned something may not be set up correctly as I have no previous experience of MVHR.

How to set up test for UK A2A heat pump performance

GarethC — Wed, 10 Aug 2016 10:57:36 +0100

How could you do this?

Am I right that you'd just need a shed of a reasonable size with an A2A heat pump installed. Would need to work out the heating needs of the shed, and probably insulate a wee bit to make it sensible.

Would you need to heat using an electric heater to confirm the heating needs empirically?

Internal target temp set to 20 degrees for between say 8am and 10pm. Monitor to track electric usage.

Wouldn't even need a whole year of data to be useful. Would even be good just to have a bit of data to see how humid/wet days affect it, and what happens in the external temperature zone of between zero and 7, where funny things MAY happen.

Ventilation MVHR for shop?

Victorianeco — Wed, 03 Aug 2016 11:13:35 +0100

The shop (7m x 8m) has no opening windows apart from in the small WC, I have insulated the loft using 350mm mineral wool and will be using 50mm PIR for IWI. The ceilings are 3m high.

There is also a basement which has no insulation whatsoever....

What form of ventilation should I use? A single heat recovery extractor fan? A MVHR unit located in the basement with exhaust and supply and the inlet located in the basement and the outlet floor level in the shop?

Heating will be by an ASHP/Air Con unit

Ideas please?

UFH - carbon saving with electric?

alexj — Tue, 02 Aug 2016 09:19:29 +0100

I'm considering UFH for our Victorian ecoretrofit, for the first floor bathroom and the open plan kitchen/living room. The bathroom will be first, the downstairs will probably but not definitely happen. My priority is to cut carbon and use non-toxic materials - this means they should be natural, biodegradable or recyclable.

I'd like advice on the type of system and on the Carbon Question (below).

Systems:
I am looking at 3 options:
- wet UFH throughout, run on gas - advantage is that we could in the future swap this to running on an air source heat pump
- electric UFH in the bathroom (easier and cheaper as we're doing this room first) and then wet in the downstairs rooms if/when we get round to it
- a sort of hybrid - a system from Jupiter, which uses a tile instead of screed, so a wet system but dry install. Advantage here is the ability to specify wood fibre insulation instead of EPS (expanded polystyrene) and not totally bury the pipes that run underneath the bathroom floor under a solid screed.

The Carbon Question:
I've installed solar pv which should generate c. 3000kWh pa. We use c. 600kWh. Both figs are based on 6mnths data, Jan-July. (I now realise I overspeccd this and should have gone partly thermal. Bugger.)

So if I install electric UFH in the bathroom, do I make a carbon saving as compared to using gas, as we generate so much 'surplus' electricity? I haven't got any storage for the pv and obviously we'll be mostly using grid electricity when we actually need the UFH on, but is the net effect one of saving carbon? I buy electricity from Good Energy.

Help with choosing thermal store

ltaylor88 — Fri, 03 Jun 2016 09:33:05 +0100

Hi I'm new to the forum but have read a lot of posts already. We have just bought a good sized 3 bed bungalow in need of refurbishment and new heat system as it has storage heaters.

We have just installed a Wood burning back boiler with 7.kw to water 4.5 to room (more on coal) the property already benefits from a Solar thermal panel on the roof which I have been plesently surprised by as I thought Id be ripping it off. and we later plan to fit oil as a backup when funds allow.

The solar is currently as it was installed just to a single coil 120ltr tank with immersion. its in a stupid place so we want to move it.

we are at the point we want to hook the stove up to the new rads but im at point where I need to chose a system. I had been planning using a netralizer (dunsley or systemlink) but there is very little info on them and what info on forums there is always seem to have some saying saying "Why not fit a Thermal Store". So.... I have been looking at thermal stores instead. we have a budget of around a Â£1000 for the store. I have found one thats fits the bill at a good price from a company that sounds like popperpylinders.co.uk they have very good reviews on there normal cylinders. It is a oven vented store with two boiler inputs(direct), Heating direct. Indirect solar and mains indirect hot water via coil rather than heatX(as we have very hard water)

Our stove is in the front room on a central single chimney. and If I go with the TS I would like to put it in the loft directly above the stove. on an open vented system

Do you recommend integral header tank?
Can I take just two feeds from stove to TS ( ie Stove vent from TS)
Is a 10% heat leak ok on the stove
Will a 250 ltr give us decent hot water supply or should we go 300?

any working schematics for my system would be appreciated.

Sorry for babbling on.

Thermal store dhw coil setup

ALwoodburner — Sun, 17 Jul 2016 00:45:08 +0100

Hi everyone,
Been following with great interest and have learnt a great deal so Thanks for that.
The setup: Galu 300l solar TS as yet not plumbed in . Store has a preheat coil and a top coil. In the room below a morso db15 boiler stove.What I have in mind is a coil around the stove pipe to act as a preheat to the preheat. It'll get pretty hot if no hot water is used for even a short time . My first question being ,would this coil need it's own expansion vessel ?
And if I fit a pressure reducing valve in the cold supply where would be a good place to put it . I'm wondering if the first preheat could restrict the flow a little ?
One last thing ,where would a pressure relief valve be best situated in same circuit.
Any help would be greatly appreciated.
Alex.