On Oct 18, 3:51*pm, "Angela" wrote:
I have a Honeywell CM67 on my central heating and I have noticed that it is
calling for heat several times an hour even though it states that it is at
the correct temperature. *When it is at the correct temp it only calls for
heat for a minute or two. *This seems a real waste. *I noticed on the
installer menu that there are 2 settings which may affect this. *The first
is the cycle rate and the default is 6, which is about as often as the
thermostat is calling for heat when it doesn't appear to need so. *Could
this be why? *If it is, can this be set to 3 ( this seems to be the lowest)
to reduce the times or does it need to be 6? *Also there is a minimum ON
time which is set to 1 minute as a default and this can be set from 1 to 5
minutes. *Does that make a difference?

Advice is appreciated.

Angela

Heating systems run more efficently the longer the cycle and wider the
swing in temp, short cycling as you are doing is wearing out all
components that switch on, since only so many cycles are built in to
any equipment. The first maybe 5 minutes any small heating system is
on is the most inefficent, it has to warm up, try both at max swing
and temp run time and see what happens, if temp swings to much for
comfort reduce it until you are happy