my halstead ace has a problem with hot water, the ch works fine until asked for hot water, it fires for a while then the overheat lock out kicks in. the pressure has always dropped when this happens, reading the other answers on this site leads me to suspect the diaphram, can anyone help? many thanks in advance.

rushers, December 2012

the boiler sounds like its overheating causing the water to overheat in the boiler. i would check the thermistor sensor for the hot water first as it may be faulty and its not to expensive and an easy change. also check the ch flow thermistor to as these regulate the temp on the boiler to stop it from overheating. also the halstead im looking at has a flow sensor for the hotwater so no diaphragm needed so pointless buying one.

kash, December 2012