Vaillant ecotec plus 438 no heating or hot water

[noddy997]

The legendary problem has returned.

I have been advised it's due to condensation in the loft. And today the loft had 55-60% relative humidity but had not heating or hw. The garage had 60-70% where the boiler is located.

I've bagged up the wiring in the loft and put a plastic tub over it too to prevent any moisture entering the wiring few months ago but that hasn't sorted it. Had no issues in the summer it's only from Oct to April this issue happens.

Got 2 extractors that are vented in the loft void and will be having these vented through roof tiles soon and will have soffit vents put in. I've put in lap vents in the roof membrane for now but that's not helped much I guess. I did redirect the two extractor fans towards the soffit where there is a 6 inch hole from an old soil pipe that used to go through the roof.

 

[Harry Bloomfield]

I have been advised it's due to condensation in the loft. And today the loft had 55-60% relative humidity but had not heating or hw. The garage had 60-70% where the boiler is located.

Those humidity levels, if accurate measurements, are quite normal. Your heating, working or not, should not normally affect the humidity level in the loft, unless you have heating in the loft. Likewise, the garage.

The way to diagnose your problem, is as true now, as it was at the beginning of this thread....

By checking the voltages at the wiring centre, and reporting back - but you need to first check your wiring centre has been setup to the default termination layout, numbered 1 to 8, left to right, like the below diagram.

 

[noddy997]

Those humidity levels, if accurate measurements, are quite normal. Your heating, working or not, should not normally affect the humidity level in the loft, unless you have heating in the loft. Likewise, the garage.

The way to diagnose your problem, is as true now, as it was at the beginning of this thread....

By checking the voltages at the wiring centre, and reporting back - but you need to first check your wiring centre has been setup to the default termination layout, numbered 1 to 8, left to right, like the below diagram.

View attachment 357929

Wiring is all fine. As stated the issue is in the colder months not the warmer months. Both hw and ch work fine from April to end of sept. Come on straight away etc. As stated much earlier one of the live wires in the loft became oxidised due to condensation but the wiring is covered up now. The only wiring that is old and hasn't been changed is the cylinder stat one or the cylinder stat becomes condensed easily?

 

[Harry Bloomfield]

The only wiring that is old and hasn't been changed is the cylinder stat one or the cylinder stat becomes condensed easily?

What does 'becomes condensed easily' mean?

As a;ready pointed out, the way to diagnose it, is by checking the voltages at the wiring centre, when the system is faulty. The voltages at the wiring centre, give all the information needed, to indicate where the issue is. Measure between the N terminal 2, and all the other terminals, make a note of them, and report back the measurement of each.