Potterton Suprima 100. Central Heating comes on above set thermostat temp?

House is very warm. House thermostat says ambient is 23 deg C, with the 'on' temparature for central heating to come on is 19 deg C. The boiler shouldn`t be pumping heat to radiators - but it is!
House thermostat appears to be working properly (digital ACL Drayton Digistat 1, no low battery warning).
Appreciate any advice, thanks!
Nick Millett, May 2005


done
check to see if the central heating zone valve has stuck open keeping the the boiler on due to the zone valve head switch being on or check if the valve is letting by...

d.., May 2005
anouther thought, is there a switch on the boiler for constant? has it been knock to this setting?

aa, May 2005
if the stat is working ok it would switch the heater off when you lowered it down, does it?

aa, May 2005
link Click here to see other fixes for Potterton.