Friend's mum's boiler.

[WaterTight]

8 yr old Potterton Suprima 80L system boiler feeding indirect vented system via mid-position port valve.

Boiler fires up for 2-5 mins then clicks off. Goes on indefinetly. Red light never flashes. Green light is on but flashing.

Problem has been occuring for several years and getting very steadily worse. Many different engineers have had a go at sorting it, none successfully - despite their reports.

Here are some:

1) "Pcb faulty. Parts required: Pcb upgrade kit. Job Report: PCB Fitted + Tested + All Working"

2) "Intermittent fault with boiler staying alight. Boiler Not staying on long enough to heat hot water. Parts required: thermistor" Fit new thermister + Tested Ok and customer to monitor"

3) "Adjusted by-pass + balancing valves + tested. Possible scale or blockage in cylinder coil. 450 x 1050 indirect."

At the moment it has never been worse. It took 8 hrs earlier to make cylinder luke warm.

It was serviced a month ago and the guy said there was nothing wrong it and left.

I asked about this on this forum 11 months ago. Puddle said it sounded like an "air pressure switch problem or flue problem." WHPES mentioned that "the controllers on the Suprima boilers are a load of pants and always screwing up."

She'll be calling in another engineer to have a look shortly who will no doubt suggest yet another unique problem at fault which will be 'fixed' to no avail.

I'm wondering why everybody diagnoses a separate problem. Is boiler fault diagnosis really that close to guesswork?

Any suggestions of things she could say to the next person who has a look to increase her chances of success?

 

[Puddle]

Well as everyone knows common faults

pcb problem with this boiler
then air pressure switch
then gas valve

thermistor not very common fault,

due to length of time of fault and if you are not re setting

My crystal ball is rolling towards ,flue problem,get flue joints checked,inner flue included,get operation of replace aps checked ,maybe replace, not much
Also get ignition leads checked especially through casing

imho

 

[tiling spread]

why not just get a new one m8

 

[villa_tom]

I would go with the fluw aswell, where I used to work we looked after a hole estate full of them and the inner flue would rot and cause the boiler not to fire although it would not go to lockout. Potterton do a flue repair kit its about thirty quid I think, we used tokeep a few on the van for exactly this type of problem

 

[Reg Man]

Do you get hot rads? or is it all of the system thats luke warm?

Green LED flashing, normaly means the boiler temperature is satisfied. Check the flow and return temperature to see if it is satisfied. This could lead you down a poor water circulation route. Once this has been established, you will know if there is a boiler or system issue. Common system problems, Pump, zone valves, bypass, no water in system, bloked cold feed. Checking if there is water in the system is easy.