Hi i have a potterton suprima boiler which is 4 years old , its firing up when switched onto heating/hot water but nothing is happening when i switch it onto just hot water .although it is firing up when on heating/hot water but its taking alot longer than usual but nothing at all happens when just on hot water any suggestions would be appreciated !

AWAW1975, July 2006

Have a look in your airing cupboard... The Suprima will normally be fitted with either 2 motorised valves, or 1 single (3 way) valve... It is this device that turns the appliance on and off by a series of micro-switches (Usually the orange [output] and grey [perminant live] wiring)... Check that these switches and valves are operating correctly first.

Also check your pump... As you may find your hot water is coming on, but not circulating, thus the boiler will turn off pretty quickly via the boiler thermostat.

ccMods, July 2006