In article ,
chris French wrote:
Put the heating switch on and see what happens. If the boiler starts
firing on-and-off then the call for heat is reaching the boiler but not
running the pump, in which case either the switches should be
interlocked or the system replumbed/wired to prevent this happening.

But hat doesn't happen, the [pump just runs in heating only mode.

Most simple programmers have the switches for both heating and water fed
via removable links. For a gravity circulation system it's usual to feed
the heating switch off the output from the hot water one so the heating
only option you have with a fully pumped one does nothing on its own.

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*I wish the buck stopped here. I could use a few.

Dave Plowman London SW
To e-mail, change noise into sound.