Worcester 28i Junior Boiler hot water when heating on only

[etmsreec]

Hiya,

I've read that people have problems with Bosch Worcester 28i Junior boilers if the water rate isn't high enough. The problem that I seem to have is that I get oodles of hot water when the central heating is on and the radiators are getting hot, but none when the heating isn't on.
Flow rate from taps seems as good as anywhere that I've lived but the water still doesn't heat unless the radiators are on.

There's only one thermostat on the boiler which I believe is just for radiator temperature, not hot water.

Any ideas please?

Ta
Steve

 

[jackecole]

Could be a faulty flow switch (turbine) - there is a DHW thermistor with this boiler also.

The turbine can stick and cause no h/w when hw is on alone. When CH is also on, the problem seems to be OK as the CH water warms the heat exchanger and hence you don't notice the difference