Ravenheat RSF82E hot water problem

[Kenten]

Hi
I have an issue with my Ravenheat RSF82e boilers hot water function.

For a number of years the hot water has cycled hot/cold/hot/cold. It happens only occasionally at the sink next to the boiler in the kitchen, more often in the bath and all the time in the shower.
I have tried reducing the DHW stat but it makes no difference.
The CH works perfectly.

The boiler fires up when the shower is turned on but after a short time the flame cuts off, the fan and pump still run. After a short time the burner fires up again and this is how it works all the time.

I had an engineer from Ravenheat who said the heat exchanger has a hot spot and the boiler is not worth fixing being 7 years old and quoted £1500 for a new one fitted, which we cannot afford. He did not look at the boiler at all, he just seemed to guess that this was the problem.

Any advice would be greatly appreciated.

Thanks in advance
Ken

 

[petertheplumber12]

Try changing the domestic hot water potentiometer GC no E23-714
If that doesn't work you may need to get someone to power flush with a cleaner the heat exchanger, Or else you need a new heat exchanger But try the Potentiometer first, its cheapest.