Suprima lockout *again* (2 years after PCB repair and following recent heat exchanger replacement)

[rjs]

Just replaced the leaky heat exchanger in my Potterton Suprima 100. It took approx 4 weeks what with HRPC ordering the wrong parts repeatedly but we managed it OK in the end.

Boiler sparked up fine for about a week but has now adopted the following mode of operation. viz: Power on, boiler stat set to maximum and tank calling for heat: fan starts running followed by ignition sparks followed by no gas and blinking red LED.

Am I right in thinking that this is the infamous 'lockout problem'? I can't remember if these are symptoms that, about 2 years ago, prompted me to re-solder every joint on the PCB. This cured the fault that I was experiencing at that time.

I can't believe that this failure is coincidental with replacing the heat exchanger but the only disturbance suffered by the PCB was the tilting of it's carrier to give access to the heat ex mounting bolts.

TIA

Richard

[Charles Fearnley]

Do you get a brief burn, followed by shutdown? If so, check the spark gap, as this is used as a flame sensor as well, and if only marginally too wide gives a "no flame" reading, leading to shutdown. If this is the case then the boiler has another couple of attempts and then locks out. My suprima is quite fussy, and only works if the spark gap is on the minimum gap spec.

Lovely boilers!

Charles

[rjs]

Charles

No burn at all now. I'll try the spark gap adjustment. As I said it /did/ run OK for the week post-heat exch replacement, which is why I fear that it's just an awful coincidence and the *********** PCB has given up (again).

I did wonder if the pressure switch air hose had developed a leak and tried disconnecting it and blowing/sucking into it. That allowed the boiler to light sans cover - very 'exciting'. I was so encouraged by this that I replaced the hose whilst the fan was still spinning - a less than good idea but I did manage to find the Steristrips fairly quickly!!

However, now it attemps to start (fan + ignition sequence) and then faults.

Richard

[Davide]

Boiler sparked up fine for about a week but has now adopted the

following mode of operation. viz: Power on, boiler stat set to maximum and tank calling for heat: fan starts running followed by ignition sparks followed by no gas and blinking red LED.

I had a similar occurrence on a Baxi SoloPF2 a couple of years ago. Th solenoid in the gas valve had gone - so check for continuity between th two solenoid terminals, as well as for 230 VAC at the solenoid pin o the PCB.

HTH

David

-- Davide