Have just had a old baxi back boiler replaced with a New Baxi Combi boiler.
When I go to turn the cold water on the boiler fires up for a split second, and sometimes I get a rush of hot water before the cold.
I have had the gas installer back out and he says it`s a boiler fault, so I got a Baxi engineer out on a warrenty claim, and he says that its a BOUNCE in the pipework and that a restrictor valve needs to be fitted.
So a little bit of help and advice would be appreacated as i am being BOUNCED from one to anouther here.
Thanks.......Confused

confused up north, May 2009

hi i bet u really understood mr k answer i had trouble & i've been in the business 27 years, anyway i guess your old system had roof tanks that are no longer there, the plumber would have cut off the mains cold feed to these this piece of pipe will have air in it as the air compresses it can force water back in2 the boiler causing it to fire, so either get rid of the air in this pipe, get rid of the pipe altogether, fit a non-return valve or there is availible a valve that goes in2 the pipework to prevent water hammer this may work as well, which ever u choose it would be down to your installer to do this free of charge if he gives a warrentee on his work.
hope this helps.

Keith Gillyon Plumbing, Heating & Building Services (southampton), May 2009

Baxi engineer seems to be correct on information. You may need to restrict flow back either NRV or hammer back valve. Will be interested to know what outcome.

Mr K, May 2009