Heating/Water Fault.

[davesparks]

I would suggest you don't go opening the boiler up, this is in the realms of the gas safety laws and without knowing what you are doing you could break the law, or more importantly risk lethal combustion products leaking into your home.

 

[telectrix]

only if he messes with the gas side.

 

[robsparky1975]

Can you not get to the terminal inside the boiler and check voltages.Its not interferring with the gas/combustion part of it.If you set HW and check with CYL stat on and off do you get switched live on/off and then check HTG with Roomstat on/off,some basic checks maybe but will speed the diagnosis up a bit.There are diagrams on the forum somewhere for a Y plan.Let us know the outcome.Goodluck

 

[davesparks]

only if he messes with the gas side.

Some boilers you have to remove a sealed cover before you can get to the electrical terminals, as a general rule any cover which requires a screwdriver to remove requires a gasman in attendance.

 

[Geordie Spark]

Afternoon Guys,
Got a little irritating fault that I cant put my finger on hopefully one of you guys could point me in the right direction. My boiler fires up continually even when its not called for, runs till boiler stat trips it off.
I havent really had a lot of time to play with it but hopefully will be off a couple of days this week and I can play a little more. I have disconnected orange switch wire from 3 port valve to try to elimiante that first but boiler fired up. I removed room stat and boiler fired up, I then removed controller completely and boiler still fired up!!!! So wtf is triggering the boiler hahaha....With the controller removed I will not be getting the HW off signal...could this be the culprit...its hard to test controller when it is plugged in as the backplate is obviously screwed to wall with controller plugged into it.?? any help much appreciated. Its a pumped Y plan with potterton prima boiler and drayton 3 port valve.

PM Chris Murphy. He'll know.

I'll be surprised if he doesn't.

 

[Steve1412]

Yeah I can get to the terminals without going into the gas side of the boiler. Hopefully will get the time tomorrow. Thanks guys. Update to follow.

 

[Spark1979]

if you disconnect the orange from the 3 port valve and it stills fires, as you've stated, its not the control side at fault i.e cylinder stat or room stat. disconnect the switched live at the boiler if it still fires up then you know its a boiler problem probably circuit board or the pump overrun relay has failed and is putting a feed to the switched live as they are internally connected in the boiler. i'd say, if it doesnt fire up then you know its getting a supply via the switched live somewhere via the controls but by the sounds of your description this has been eliminated already, you also shouldnt run this boiler with the main cover as stated before as it is a positive pressure boiler.

 

[Meggerman]

Some boilers you have to remove a sealed cover before you can get to the electrical terminals, as a general rule any cover which requires a screwdriver to remove requires a gasman in attendance.

Like that happens

 

[Meggerman]

Yeah I can get to the terminals without going into the gas side of the boiler. Hopefully will get the time tomorrow. Thanks guys. Update to follow.

The key thing here is to check at boiler across S/L terminal and N and from there you can determine if it is a boiler fault or external control issue.

 

[Spark1979]

if its a faulty relay he'll get 240 between n and sw/l which wont help as to why the boiler is firing, thats why he need to disconnect then check the terminal

 

[davesparks]

if you disconnect the orange from the 3 port valve and it stills fires, as you've stated, its not the control side at fault i.e cylinder stat or room stat. disconnect the switched live at the boiler if it still fires up then you know its a boiler problem probably circuit board or the pump overrun relay has failed and is putting a feed to the switched live as they are internally connected in the boiler. i'd say, if it doesnt fire up then you know its getting a supply via the switched live somewhere via the controls but by the sounds of your description this has been eliminated already, you also shouldnt run this boiler with the main cover as stated before as it is a positive pressure boiler.

The orange of the three port isn't the only thing that gives the boiler a switched live, the normally closed contact of the cylinder thermostat also does this.

 

[Spark1979]

sorry your correct dave but id assume he would have disconnected the sw/l to the boiler from the wiring centre not just the orange.

 

[Meggerman]

if its a faulty relay he'll get 240 between n and sw/l which wont help as to why the boiler is firing, thats why he need to disconnect then check the terminal

I agree he should disconnect. I just meant carry out tests there and not at wiring centre as there is other components that can energise the S/L as has been pointed out..

 

[Steve1412]

Thanks for the replies guys...quick update. I disconnected Swl from boiler and amazingly it fired up again!! Just got to the pump run on stat and then a minor family emergency had me cancel my playtime again. Hopefully get an hour tonight. I assume the pump run on stat has a switched live and perm live changing over to the pump. Will try to test it tonight.

 

[davek]

Hi not read all post but my son in law is a gas engineer. If we find something like this and tried everything else disconnect supply stick in plug to and see what happen with no control circuit on it