how can I fix my halstead ace hot water?

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