Potterton Suprima 60L - please help!

[Gaz7]

Hi all,

I've just moved into a new house which has a Suprima 60L fitted. Within a week, i was suffering from the 'lockout' problem that seems so common after reading this site (flashing red light, requires a push of reset to get the boiler to work, and a new PCB to fix).

After a couple of days though, the problem got worse, and instead of locking out, the boiler just kept blowing the 3A fuse.

So, i got a new, revised PCB (the one that comes as a kit with the wiring loom etc) and fitted this - and the problem seemed to be solved.

However, a few days later, after working perfectly, it's blowing it's fuse again. I can't seem to find much info about the fuse blowing issue - can anyone help? Getting a bit desperate now as the board was £180 and no hot water and heating is a nightmare...

Also, when it is working and the heating is on, it seems to fire for a few minutes, then click off (LED flashing green) for a few minutes, and then fire again. It didn't do that with the old PCB. Surely that's not good for it?

Any help/suggestions appreciated.

Gareth.

 

[Slugbabydotcom]

Most likely the fan or pump taking the fuse out. Gas valve could do it but is less likely. Check the resistances. Has the fan or pump been noisy lately?

 

[Gaz7]

Thanks for the reply. The fan and pump don't sound too bad, but I've literally just moved in so I've no 'normal' noise to compare them to.

How should I check the resistances? Is it just a case of power off and then put a multimeter across where the wiring usually goes? What kind of figures should I be looking for?

Gareth

 

[Gaz7]

It's now got worse, and won't run at all, even for a few minutes when a new fuse is put in - it just pops the fuse straight away, so something must be shorted... Does anyone have any ideas of what i should look for or tests to do?

Gareth.

 

[mickyg]

why not unplug the fan, gas valve and pump, try it and plug one in, one at a time. it will cost you a couple of fuses but its a crude yet easy way of checking.

ps, I should also advise that when you disconnect the fan you do so from the pcb as it is contained within the sealed chamber of the boiler.

 

[Gaz7]

Ah, good plan. i'd like to try the pump first as this is where i have my suspicions - the pump looks pretty old and corroded.

The boiler is in my garage, and the pump is in the airing cupboard upstairs - it's a Grundfors one i think. It has a white cable coming out of it disappearing straight into the wall - what do i need to do to turn this off?

Gareth

 

[mickyg]

turn off the power, disconnect the wires from the pump and make them safe(into chocbloc or bit of tape, your choice). Turn boiler stat to off, turn on power, turn up boiler stat but if boiler lights don't allow it to run for more than a few seconds as it will overheat. Or you could turn off gas supply, as you will still get power to gas valve and fan for a while on ignition attempts(about 7 on new pcbs before lockout).