Heating/Water Fault.

[Steve1412]

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.

 

[Guest111]

Faulty frost stat?has anything been changed or has it just started doing this on its own?

 

[Steve1412]

Thanks for reply. As far as I know I dont have a frost stat. Unless it is inside the boiler itself?

 

[Guest111]

Ok best trick is to get yourself a drawing and go through it,it will soon make sense and hopefully all will appear clear,it could be a fault on programmer,does it go off if you remove programmer?

 

[telectrix]

turn it off. get a jumper for when it gets chilly. sod off british gas,

 

[Guest111]

turn it off. get a jumper for when it gets chilly. sod off british gas,

Spare meter?

 

[telectrix]

hi, phil, from marmaris. relaxing in the sun. here till sunday.

 

[Guest111]

hi, phil, from marmaris. relaxing in the sun. here till sunday.

lucky man,sat here trying to decide wether to have another breakdown or just hibernate 'till things improve.lol

 

[Steve1412]

Haha...i will have to put the wifes frillys on to keep warm!!!..I had the stat, tank stat, controller and valve sw wire all removed and it still fired up...thinking of calling Ghostbusters!!!..didnt want to go into the boiler but I suppose needs must... I have the drawings required...was hoping somebody had come across a similar one....thanks for help...and have an Efes on me!!!!

 

[Guest111]

is the boiler actually firing up or just running the pump,some have an overrun to heat heat from the boiler before it shuts down.

 

[telectrix]

Haha...i will have to put the wifes frillys on to keep warm!!!..I had the stat, tank stat, controller and valve sw wire all removed and it still fired up...thinking of calling Ghostbusters!!!..didnt want to go into the boiler but I suppose needs must... I have the drawings required...was hoping somebody had come across a similar one....thanks for help...and have an Efes on me!!!!

EFES not too bad for lager, as it goes. it's free. getting withdrawal symptoms for decent british ale and a bacon& egg buttie, though.

 

[Steve1412]

Yes the boiler is also firing up?...

 

[Guest111]

if the boiler is firing with everything else disconnected then I'd suggest a pcb fault.

 

[Steve1412]

Oooo I found the turkish eggs taste like what eggs used to taste like when I was a kid but the Bacon...its super streaky!!! lol

 

[Steve1412]

if the boiler is firing with everything else disconnected then I'd suggest a pcb fault.

It doesnt have a pcb?....OMG...its a poltergoost!!!haha

 

[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

 

[Steve1412]

UPDATE....Finally got chance to spend a bit of time with this. Turned out to be pump over run stat shorted putting perm live to boiler!!! Order new one and stuck it in...luckily this is fitted outside the gas area!!!...Job Done....Thanks for your help all!!!

 

[Barrymk]

i know thus is an old thread but it sounds like the hot water motorised valve is faulty, either the body is jammed and needs freed up or the internal switch is jammed open. removing the orange cable on the valve will stop the boiler firing on its own.

 

[davesparks]

i know thus is an old thread but it sounds like the hot water motorised valve is faulty, either the body is jammed and needs freed up or the internal switch is jammed open. removing the orange cable on the valve will stop the boiler firing on its own.

No it doesn't sound like the motorised valve is faulty, it sounds like the overrun thermostat is faulty.
This is based on the fact that the OP has stated that the overrun stat was faulty and replacing it fixed the problem!