I`ve carried out numerous repairs to my combi over 12 years , but struggling with this one ... C / Heating seems OK , but hot water .. shower .. fires up fine and provides hot water for approx 3 minutes before shutting down for a minute , then firing up again ?? replaced air pressure switch .. no change ... is there a flow sensor ??

dave s, April 2011

my boiler is doing exactly the same been told that its the calcium in the boilers pipes from the water that causes it and the only answer is a new expansion tank £300/400 qiud or cut your losses and get a new boiler

stuart, April 2011

no .. its not just the shower , it does the same on tring to run a bath or running the sink tap .... could it be the hot water thermostat ? ?

dave s, April 2011

if it's just the shower causing this then the shower is not allowing enough h/water through check flow rate of shower clean shower head and check shower valve filters

brian, April 2011