This mainly happens when hot water tap is on as it runs warm and then freezing and we need to reset the boiler. It did happen also when we were on holiday. We came back and house was freezing. Heating was on timer but had tripped out. Prior to this it had only ever happened when a hot water tap was on. British Gas been trying to fix this for past 2 years and have replaced just about everything but still problem is there. Any advice as I am at my wits end with this. It's now going about 4 times a day and is a pain in the but when happening whilst bathing kids as heating in garage and need to take kids out of bath to go and reset.

Angela, South Lanarkshire, May 2008

heat exchanger is dual pass exchanger, no dhw plate exchanger on this little fella

iain, May 2008

is your boiler also kettling (bubbling when hot) if so the main heat exchanger may be partially blocked and your whole system in need of chemical flushing.

Or if the problem is on dhw only, it maybe a blocked - partially blocked dhw heat exchanger allowing the water to boil due to reduced flow, this would send your boiler to lockout on the dhw high limit stat.....

either way should be a straight forward enough check for a technician to perform, all they have to do, is when it's locking
out to check the limit stat with their multimeter to see if thats where the problem lies!

T, May 2008