In article ,
Malcolm H wrote:
If the boiler was not designed to have a pump overrun feature is there a
control available which can be added retrospectively. e.g. is there a
timed control available which will allow the pump to run for a short
time after each switch off?

I added this feature to mine. ISTR I had to change the pump switching to a
mains relay, as simply feeding mains to the pump after the thermostats
were satisfied caused problems by feeding those volts elsewhere - although
that might well not be the case with others. I made the timer circuit
which is set for 30 seconds. Basically, a small low voltage power supply,
a 555 timer and a relay. Cost nothing as I had all the bits lying around,
but probably no more than a tenner to buy.

At the time, I investigated finding a ready made unit but couldn't. And,
of course, most boilers have these built in now.

--
*If at first you don't succeed, then skydiving definitely isn't for you *

Dave Plowman London SW 12
RIP Acorn