Potterton Suprima trips mains when pump switches on

[sgb22]

I've got a Potterton Suprima 60 which about three years ago started doing the lockout problem. Thanks to some good advice from one of the many posts here on this subject, I replaced the PCB and it worked fine. Two weeks ago it started showing the same problem. I ordered the most recent PCB and then fitted that.

The instructions told me to remove the fan, which I did, not realising that this was 1) completely unnecessary for the PCB replacement 2) means I've broken the seals and potentially got a CO leak 3) I've ventured well beyond what is allowed when I'm not CORGI registered.

Is there a reason Potterton will have told me to do this in the instructions? Any clues as to where I can get the replacement seals?

I reconnected the boiler, and whenever the pump started it blew the fuse/tripped the RCD. The previous installer had connected only the pump live and earth, not the neutral.

I'm resigned to getting a professional in to replace the whole dodgy thing, but given the shortage of plumbers and lead times I would appreciate any tips that could let me get it running to keep the kids warm for the next week or two.

 

[ChrisR]

...previously - live on live, and earth on earth, and no neutral??? The pump surely wouldn't have run.

Presumably you got your pcb off the back of a lorry or you'd be getting seals from the same place. You might find that it's just a faulty board, sold as new. Happens all the time.

Several of us work in London - what's your postcode?

 

[sgb22]

Pump is wired in to the timer and running - the pump input lines on the boiler are only connected to the Live and Earth. Going to buzz the pump cable through later in case I damaged the insulation pulling the cables through.

Am I correct in assuming that the pump input to the boiler should be connected in parrallel with the pump itself?

Have located seals - used mjtcontrols (where I got the legit pcb from).

Postcode is W6 (Hammersmith). Where do you cover?

 

[bobbo85]

the pump has a ,the name of the part has gone out my head,were the wiring goes ,is the small round part with 2 rted wires from it ,i find when the pump is blowing the fuses or tripping its that

 

[bobbo85]

can you disconect the pump and see it stops

 

[bengasman]

oops

 

[sgb22]

Found some honeywell wiring diagrams and did some more investigation.

Have I understood the control process correctly?

Timer switches on the motorised valves. When the either valve opens it closes a switch which provides a live 'call for heat' input into the switched live input on the boiler. The boiler then drives the pump directly (providing the overrun).