No hot water, heating ok

Mister_G

AndyPK wrote: »

Has nothing to do with the 3 way valve electrics

Well on my system the microswitches in the head certainly control the HW and the CH.:)

michaeljs

When I went to check part numbers, I had another play....

Setting Timer to CH on, causes CH to come on as hoped.
Setting Timer to HW on, causes 3way to move to HW position but then nothing else happens.
Setting Timer to CH on, again causes CH to come on. Then setting timer to HW on as well, causes 3way to move and then CH switches off.

If that is food for thought as to whether this is more likely to be header or stat (or something else).

Thanks

AndyPK

The immersion and boiler use separate theromstats in the tank.


Do you have a picture of your stat/tank ?


For 3 way valves the switches only enable the boiler when in CH mode.

AndyPK

It's never a bad idea to replace the valve heads, as they do wear/fail, but I don't honestly think its the problem in your case

Mister_G

It could still be either.

If you try turning the temperature control on the stat, can you hear it click when it switches on? Ideally a multimeter would be the best thing to use.

Failing that, if you are confident with electrics, then remove the cable from the stat and join the wires together (brown and blue only!), insulating them with tape. This will bypass the stat and will prove if the header is the problem.

Only do this if you are Confident and AFTER you have switched off the supply!

michaeljs

I have recently changed the header unit, so it would seem unlikely that's the problem, though not impossible. It worked fine for 1 month until last weekend.

There is no clicking from the stat at all, in either direction.

I had thought about joining those wires, so now that you've suggested it I'll give it a go.

I'll try to post a pic later, depending on the outcome of joining the stat wires.

Thanks.

michaeljs

Sorry, there is a click on the stat, just it's so low down I didn't notice it at first. It clicks at what must be about 5 or 10 degrees (the scale only goes down to 40).

Mister_G

michaeljs wrote: »

Sorry, there is a click on the stat, just it's so low down I didn't notice it at first. It clicks at what must be about 5 or 10 degrees (the scale only goes down to 40).

That would be about right if the tank is cold. However, it clicking doesn't mean to say that the contacts are making correctly.

Without a multimeter to check, I reckon joining the wires is the only sure fire way of checking.

michaeljs

When you say join the brown and blue wires..........

michaeljs

https://drive.google.com/file/d/1DGk6hv6JMYvNZ4hIFLBpbNQX8H6_kAno/view?usp=drivesdk