This boiler has worked perfectly, since I had it fitted 3 years ago.

Recently, however, when trying to run the shower, the hot water runs fine until turning on the cold tap to reach the required temperature - the hot water 'demand' then just switches off.

The heating system still works fine, as it always has.

Does anybody out there have any idea what is going on here?

Barry, June 2008

I have exactly the same problem with the Worcester Bosch Greenstar. Everything worked fine for the first year that I lived here. The problem occurs with the shower and the kitchen tap. I have no idea if it's a plumbing, boiler or water company problem. Help!

sarah, April 2009

Possibly the problem may be caused by a worn mixer tap, either on your kitchen sink, or more likely a worn shower mixer. Although Brit Gas should have told you this. Cold water is crossing over to the hot supply via the worn mixer possibly. Causing many problems.You can test by dismanteling your shower and blocking them with pushfit stoppers, although it is the shower with the problem, but maybe you will notice other probs not mentioned here are OK now. hope this helps.

Jex, August 2008

Interestingly we have exactly the same problem with exactly the same boiler and have had British Gas engineers out 6 times to try and fix the problem. They've replaced the heat exchanger, thermistor and some other parts and the problem still persists. They now said its a problem with the pipes/taps which doesn't make sense as we've not changed anything in the house and it's been working fine for over a year ! It could be that water pressures have dropped but getting the water company to come out and monitor the pressure is like getting blood from a stone !

CC1508, July 2008