S plan / bypass gate valve / pump gone

17 Apr 2015
Reaction score
United Kingdom
Hi all
My dad had a new boiler, low loss header and pump installed a couple of months ago, S plan system, and a few weeks later the new (external) pump broke. When it was broken, I was round there and observed the system firing up (programmer set to heating only), zero noise from the main pump, but the boiler (Ideal Vogue) internal pump running, red hot pipework up to both zone valves, but both zone valves (even the heating one) were closed. So cold pipes the other side of both zone valves. This seemed to be a bit of a one off, like the valve occasionally got stuck, but worked fine most other times.
There's a 15mm pipe with a gate valve on it, acting as a bypass just before the zone valves. I can't move the gate valve so no idea if it's open or shut.
Anyway - my question is, if that gate valve is shut, AND neither zone valve opened (because one of them was stuck it seems), I reckon that could possibly have caused the pump to fail - as everything's fired up and red hot but no bypass. Possible, or am I barking up the wrong tree? any thoughts appreciated, just want to avoid it happening again. Plumber not been back with new pump yet, all I know is he diagnosed the other one as deceased.
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You dont need a bypass so the gate valve should be closed or got rid of.
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Thanks both. So even if the pump can’t pump (due to zone valve stuck closed) it’s not going to damage it? Guess the new pump was just a duff one.

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