On 22 Mar 2004 05:32:21 -0800, stevep wrote:

I have a gravity fed HW and pumped CH system with a programable
thermostat. If I have the thermostat programmed to come on all day
inc. overnight then the boiler keeps tripping in to heat the water
despite heat not being required for the CH.
Can I fit a thermostat to the airing cupboard tank so that when the
room temp is OK the boiler will not light up or is there some other
easy solution?


Honeywell 'C' plan (or equivalent) is probably the classic answer
(See Sundial plans on Honeywell web site.) In this you use a zone valve to
stop the gravity circulation when the H/W tank is hot.

Alternatively (or in combination) a Danfoss TP9 programmmer/thermostat
would supply power to the boiler when either:

a) There is a need to heat house (i.e. room thermostat calling or more
precisely the programmer uses its sensor and determines that heat should be
supplied by powering the pump and the boiler.)

b) When you want to heat H/W e.g. 7-9am and 5-9pm

You can download the TP9 installation instructions from
http://www.danfoss-randall.co.uk/default.asp

Michael Chare