Green Building Forum - MVHR overheating warning Tue, 19 Dec 2023 04:01:17 +0000 http://www.greenbuildingforum.co.uk/newforum/ Lussumo Vanilla 1.0.3 MVHR overheating warning http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17808&Focus=304407#Comment_304407 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17808&Focus=304407#Comment_304407 Mon, 27 Nov 2023 14:28:00 +0000 Rex
The manual reset passed, the other one which I assume should be closed, did not. Perhaps this is the problem? But that does not make sense as my rest method (power off, wiggle the manual reset, disconnect and reconnect the stat terminals) plus control pane reset and ti works, until the next time.

Anyway, phoned Flexit in Norway and was advise that may be a new stat would be a good idea. However, not only are the bloody expensive from the official sites, but due to Brexit, they are unable to place an official order.

But the beautifully spoken Norwegian lady on the phone,kindly offered to put one on the post for me, free of charge. No official order, no problem posting to the England. Just like the service that one normally gets in the UK!!!!

Time will tell if this solves the problem.]]>
MVHR overheating warning http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17808&Focus=304442#Comment_304442 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17808&Focus=304442#Comment_304442 Fri, 01 Dec 2023 17:24:49 +0000 Rex
Unfortunately, the alarm light (overheating thermostat) is still illuminated and the unit will not run; don't know what to look for next.

Any suggestions?

Thanks]]>
MVHR overheating warning http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17808&Focus=304444#Comment_304444 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17808&Focus=304444#Comment_304444 Fri, 01 Dec 2023 20:17:44 +0000 djh MVHR overheating warning http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17808&Focus=304453#Comment_304453 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17808&Focus=304453#Comment_304453 Sat, 02 Dec 2023 15:53:30 +0000 GreenPaddy
However, that doesn't really explain that it runs ok all summer, and then has an issue in winter? Maybe the poor contact shrinks enough in the cold to go totally open.

Wait for the next failure, and then do your continuity testing, BEFORE trying the old switch off/on to correct it.
Test from the mains IN across to the motor (as djh suggested). That should show NO continuity. Work your way back, connection by connection, until you get the continuity beep. That will pinpoint the offending connection.

Intermittent faults can be a nightmare, especially if you get called out to look at it - can't find a fault that has disappeared.]]>
MVHR overheating warning http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17808&Focus=304457#Comment_304457 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17808&Focus=304457#Comment_304457 Sat, 02 Dec 2023 19:27:06 +0000 Peter_in_Hungary Posted By: GreenPaddyIntermittent faults can be a nightmare, especially if you get called out to look at it - can't find a fault that has disappeared.
+1 to that.
bin there, dun that......lots.]]>
MVHR overheating warning http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17808&Focus=304462#Comment_304462 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17808&Focus=304462#Comment_304462 Sun, 03 Dec 2023 13:16:33 +0000 Rex
I do have an illuminating voltage detector pen so can give that a try.

Whatever it is, cannot be too complex, just a matter of find it. Tend to believe that it is external temp related as last night, here is leafy Surrey, when it came on at 22:00, the outside temp was around -1C and with all my fiddling with the manual reset and stat connections, could ot get it into a mode where the control panel reset worked.

But this morning when the ambient temp was around 5C, it came on as normal without any fiddling at 06:30.

At the moment, the MVHR unit is off, so while it is 'cold' I have been to dig deeper. Turned it on and of course, it starts. Used my voltage checker and with my limited knowledge, all I can say is that within the circuit board cover, virtually every black wire registers live.

What I don't understand is that both motors are rated at 230V and when running, neither cable directly connected to the motor makes my tester flash. Motors running but seems like 0V, which is obviously not possible!]]>
MVHR overheating warning http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17808&Focus=304463#Comment_304463 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17808&Focus=304463#Comment_304463 Sun, 03 Dec 2023 16:45:28 +0000 djh Posted By: RexWhat I don't understand is that both motors are rated at 230V and when running, neither cable directly connected to the motor makes my tester flash. Motors running but seems like 0V, which is obviously not possible!I worked in a TV repair shop when I was a lad. One day I went out with one of the real employees to investigate a faulty TV. The mains cable was suspicious and had a joint in the middle. He took the joint apart and tested both the 'live' ends and both didn't light his light. So he thought the circuit was switched off. So he was very surprised to get a shock when he touched the ends. The joys of nylon carpets! (i.e. insulating)

Which is a long way of asking did you have a good ground yourself?]]>
MVHR overheating warning http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17808&Focus=304477#Comment_304477 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17808&Focus=304477#Comment_304477 Mon, 04 Dec 2023 16:17:04 +0000 Rex MVHR overheating warning http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17808&Focus=304480#Comment_304480 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17808&Focus=304480#Comment_304480 Mon, 04 Dec 2023 20:01:14 +0000 djh Posted By: Rex... a voltage checker. If there is current, the light flashesUsually these are voltage checkers as you say. They don't detect current and don't need any to be flowing.

As I said "did you have a good ground yourself?".]]>
MVHR overheating warning http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17808&Focus=304668#Comment_304668 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17808&Focus=304668#Comment_304668 Mon, 18 Dec 2023 13:30:06 +0000 Rex
The new, non-manual rest thermostat from Flexit has been install, as has a manual rest stat from one of China's finest manufacturers. The result to date is everything is working as it should with no alarm activations.

n the past however, it is my suspicion that the alarm was activating when the external temperature was near 0C and since fitting the new stats, the external temp has generally averaged 5C+, even in the early morning. I wait for the near 0C weather conditions to see what happens.]]>