Electronic wall stat

[judoginge]

Hi, just qualified and started to find that the real work is not as easy as the college made out!. Whilst changing a ball valve on a job the customer mentioned that the heating is always on and the rad on the landing is always hot. When checking it turned out that all the other rads had the TRVs turned off so keeping them cool. When checking the wall stat i noticed a sticker on it that says something like " Relay controlled electronic wall stat. If no mains power no `click` will be heard and a constant call for heat will remain". when you turn the dial there is `no click`. This stat was apparently fitted about 2 years ago and the system was powerflushed at the same time and the TRVs fitted. It looks like the problem has been ongoing ever since and the rad has indeed remained warm all of this time. I am obviously thinking that the stat is the wrong type as the heating system is approx 20 years old and I should change it for a mechanical one, Hope someone can help as I don`t want to go in all guns blazing to fix it and it still not work! Can somebody please advise? Thanks in anticipation.

 

[migoplumber]

if its an electronic stat, you wont necessarily here a click as you do with the more common mechanical stats. the only way to test its working is with a multimeter. the click you mention would be heard at the relay if that is indeed how its wired up.
you need to post a little wiring diagram, or at least a little more info!!
its a good question for jason s.

if it has never worked, sound like its been wired up wrong from the beginning, and over complicated!!

good luck
shaun

 

[Jason.S]

Well, i can only say that i agree with shaun.

Firstly i would check to make sure there is voltage at the stat.

 

[stevetheplumber]

think the electronic stats have a permenat live to then as well as a switched pairi know ive never quite got to grips with them and tend to sling them away in favour of a mechenical cant beat a good click

 

[judoginge]

Thanks for the tips gents. I have been to have another look. The pump is running when you ask for HW and the rad warms up. Not sure but I think it may be the 3 port valve? It was replaced around 18 months ago when all the other work was done and hasn`t changed the fault. Apparently the fault has been there for around 10 years when the boiler and most of the system was replaced. Customer was told that the beauty was that with having HW on 24/7 you can just turn up the TRVs to heat a room when you need it!..

 

[smoggs03]

run!!!!

 

[Plucky]

Sounds to me as if the system is mispiped badly and the customer has been told a load of horsepoo