Potterton 40 blowing pcb fuse and 3amp fuse

11 Apr 2008
Reaction score
United Kingdom
Some advice will be appreciated. Got home and found the house cold. Check the boiler and controls and evertyhing was dead. I suspect the 3amp fuse had blown. Checked fuse which was blown and replaced. When I turned the 3amp plug back on it blew the 3amp fuse straight away. At the same time of this happening I noticed a small spark (short) coming from the pump capacitor wiring at the Grundfos pump. Checked wiring cannot find anything wrong. Now when I replace the fuse again the PCB fuse blows. And when I replace PCB fuse the 3amp fuse blows. Everytime I notice the short at the pump capacitor!! Could this be the pump capacitor blown or perhaps the PCB board? Your help would be appreciated.
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Try running the pump from a seperate fused supply (with a 3 Amp fuse). Probably need a new pump.
Thanks for your reply. Will give it a go first thing in the morning. If the pump runs from the separate supply could it then be the PCB board? and is it common for these symptoms to occur when the pump goes.
If the pump capacitor is shorting then you will need a new pump...unless you can source a replacement capacitor of the correct type.
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Gasguru. Thanks for your advice. I replaced the pump and everyting is working fine. Owe you a cold one. Thanks Michael

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