You could always remove the pump and check the impeller, check for debri's etc - trying not to make it obvious you have remove the pump head (don't mark bolts etc) if you can get one for nowt - try a new pump.
I would only get the manufacturer out if -
you're sure the boiler is at fault, the system was flushed and inhibitors were added - if they weren't then they may charge you as it might not be a faulty pump that caused the pump to fail.
If you think changing the valves would help - do it, wont take long or cost much.
But with F22 flashing up - even just briefly and the radiator problems I would try a new pump.
hi htg engineer. i av got a pump which came off a system fed by a back boiler, the pump works ok my uncle just changed to a combi so i took the old pump thought it might come in handy lol) if i take head of that will it be suitable for my boiler its a vailant? cheers bazza
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