In message , No-one
writes
Trying to isolate the problem:-

I have replaced what I thought was a faulty water pump. However, it
does not run when the power is applied. The motorised valves are old
and I am sure the hot water one is dud but the central heating one
worked. If this one also had failed, would this stop the water pump
from switching on?

You need a proper one - like mine

http://i50.photobucket.com/albums/f342/radenn/Pump.jpg


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geoff