Intermittant hot water from combi boiler - can anyone help please?

LouiseK_2

We have a baxi bahama 100 combi boiler (about 6 or 7 years old) and we are having problems with the hot water. When the tap is running, its fires up for about 6 seconds then cuts out, then re-fires, cuts out, etc. resulting luke warm (at best) showers.

Earlier in the year, we had a similar problem and (I think) we had the flow switches changed. This didn't solve the problem so we then had a power flush which appeared to solve the problem. Now the problem has come back.

Can anyone advise what the problem may be, how to solve it (ourselves preferably -we've spent loads of money on the boiler already)?

Many thanks

mort58

Hi LouiseK

I'm no expert! but the bolier is probably cutting off and on because the water is heating and not flowing quick enough,would have put it down to scale myself......

strawberrylane

LouiseK, we had exactly the same problem with our 8 year old combi bolier about 2 months ago. The engineer we had fixed the problem on the first visit. The problem in our case was that the "shuttle spring" in the 3-port (divertor) valve was badly coated in black scale so that the spring (and hence the valve) did not operate. The engineer had to dismantle the valve to discover this and then replaced the shuttle spring. This solved the problem. Most engineers would probably just have replaced the whole divertor valve. At the same time, the engineer said that the heat exchanger for the domestic hot water was also badly coated internally with black scale (he took it out of the boiler and showed it to me). This apparently meant that the hot water was not getting as hot as it should, but this was not the cause of the main problem that you described, but we also had the heat exchanger changed as well. We now have piping hot water. The costs were: Call-out charge £50 (fixed fee), 3-port (divertor) valve shuttle spring £15, valve diaphragm £5, heat exchanger £40 (for a refurbed unit - a new one would have been £110). So all in we paid £110 to solve this problem.

Hope that helps.