Tony Bryer wrote:


The pipe stat will have n/o and n/c contacts. Common goes to pump,
n/c to boiler call, n/o to permanent live. Boiler switches on and
pump runs. When the set temp is reached the stat switches over and
the pump keeps running until the system cools down.

Thanks - I can see that would work. However, the original problem is
that the boiler restarts my Alpha pump every time it fires (so it speeds
up for a while before settling down again). This (the restarting) would
still happen as the pipe stat contacts changed over (although I
appreciate it would be much less frequent than it is now).
I'm minded to try the delayed off relay approach - at least I can
contain that in the boiler cupboard, a pipe stat would have to be external.