Potterton 100 combi HW but no CH

[joker1981]

Hi all,

When i run the HW tap there is a red light that comes on inside and the boiler fires up and i have hot water so i presume all pumps etc are working fine.

However... When i push the swith to turn on the CH, whether on constant or timer i get absolutly nothing...no red light, firing or anything.

The boiler sems to over run for about 10 -15 seconds after water is switched off but then goes off.

If anyone can help me i would be very grateful, i know very little about boilers so step by step in laymans terms would really help.

thanks in anticipation

Allison

 

[baxpoti]

Lots of recent posts on this problem
Check back through and see if any info helps

 

[ChrisR]

No quite this problem much, I think?
You need to check the "call" signal is arriving at the boiler. Needs voltmeter and the circuits - partsarena.com/baxi

 

[joker1981]

Hi, thanks for the replys. I have looked through lots of posts that are similar to my problem but couldnt make anything from them.

If you think it sounds like it could be a problem with the main circuit board i could get a metre and check the voltage between the two points if some one could tell me which they are.

Or if it sounds like the circuit board is definatly the problem i could fit a new one as they only seem to be push on plugs on the board.

Thanks
Allison

 

[Rob]

Are we talking about a Puma here? Known quite a few of these to fail on CH because if the main board.

PL2/3 along the top side seems to be controlling whatever part is needed. Could just be dry joint or completly burnt out which i saw 2 weeks ago. Still left HW working though!

Or just external control problem!

 

[Caspar]

Had exactly the same problem with my Puma last year - turned out to be main PCB had burnt out on the pins where one of the the connectors plug in.
A new board fixed it.

 

[Agile]

The boiler sems to over run for about 10 -15 seconds after water is switched off but then goes off.

The clue is here!

The DHW flow switch is jamming on! That has been covered many times here. It is often accompanied by overheating and banging noises.

I am not so sure that you are going to be able to fix it yourself and you will probably need a competent boiler engineer who is comfortable working on your model.

Tony

 

[joker1981]

Hi, Seem to have the CH working now but only when it is switched over to timer - not on constant.

I followed the wires from the CH switch to "PL2" on the main circuit board, then i disconnected and then re-connected the connection - after that hey presto i had CH back even if it only worked on the timer.

I suppose all this points to a fault on the circuit board so maybe i will be better off changing it.

thanks for all your help.

allison