Potterton Performa 28i - Intermittent CH/HW problem

[MarkR147]

Hi

His is my first post and I am hoping someone can help with my boiler problem please.

I have a Performa 28i that was fitted about 7 years ago, serviced regularly etc. Recently the CH and HW started to play up and the following symptoms occured:

1. Started to notice that when the CH was trying to come on the burner kept igniting then going off every 5-10 seconds for about 3/4 times then the burner would ignite properly.

2. The HW then failed but the fault showing was the CH LED flashing. Managed to get it sorted by eventually resetting the system but the problem continued and then no CH.

3. I had a spare PCB (long story!) which i fitted and this seemed to resolve the CH/HW problem but I still noticed this problem of the burner keep igniting then going off immediately a few times.

4. Yesterday the HW failed again and the CH LED was flashing and the burner was not igniting.

Have worked through the manual but I really am struggling to understand the flow charts and every solution seems to end with 'Replace PCB' which has been done so I know it is no this (unless PCB is faulty?).

Would appreciate any advice please.

Many thanks

Mark

 

[picasso]

test the thermistors, they should be 11k Ω at room temp reducing in resistance as the temp increases,

or just buy a couple stick them in and hope for the best

 

[albadiy]

hi mark. cant really help. i have a potterton performa 24 with very similar fault. had a gas safe engineer look at it for two hours without being able to find the fault. would really like to hear the conclusion to your problem.
good luck
from a gas boiler hater

 

[MarkR147]

Picasso

Thanks for the reply - where are the thermistors positioned in the boiler?

Thanks

Mark

 

[picasso]

You will need to drain the boiler to change the primary thermistor.

View media item 46226

 

[albadiy]

hi guys. just wondering if i am allowed to ask picasso a question about my performa 24 on this post.
cheers

 

[picasso]

Probably better to start a new thread.

 

[Baxmax]

C.H Primary thermister is "dry pocket" no need to drain.

 

[MarkR147]

Picasso/Baxmax

Really appreciate your help guys and hopefully I can resolve the problem.

Many thanks

Mark

 

[albadiy]

hi there . my performa 24 had a similar problem as yours and it turned out to be the thermistor which is not expensive, and easy to change myself.
am very interested to know if yours was the same.
thanks

 

[MarkR147]

Albadiy, Picasso, Baxmax

Thanks for all the help and the problem was the thermistors. Bought a couple on Amazon and replaced them both as I had the boiler front off and perfect ever since.

Regards

M