Alpha 280E Intermittent DHW & lukewarm CH

[yachtboy66]

Please can someone help with identifying a very frustrating issue I have had for some time. I have had several plumbers who have tried to fix it but I am sure they do not know the real problem.

When I have a DHW flow, the red LED lights and the boiler lights up. It stays on for about 20 second and then goes out. As it still recognises a DHW demand it then tries again and the same thing will happen. It makes the shower (or tap) run hot the cold etc.

If the CH is on it only gets luke warm, even with the thermostat set to max. The Radiator LED stays on but there is no bolier action for long periods of time and when it comes on only stays lit for 30 secs or so.

The diverter diaphragm has been changed.

 

[bab]

Not that clued up on these boilers. I think it might be the hot water diaphram washer u had changed. It could be a senser but it does sound like the heatexchanger's full of tish.

 

[Agile]

There are several possible causes and it seems as if you have at least two different faults.

The fluctuating DHW is probably caused by dirt in the heat exchanger.

I suggest you try to get a local heating engineer rather than a plumber.

Tony

 

[yachtboy66]

Thanks for reply

The Heat Exchanger appears to be clean (no furring or limescale if this was the blockage type you were referring to). Is there any kind of check I can do to determine if this is the problem.

Could it be a sensor?

 

[Agile]

I was referring to the secondary HE ?

You should check the cold resistance of the sensors.

Tony

 

[yachtboy66]

ALL MENDED

It was the sensor that cuts out the boiler if it gets to hot. (£9)

It burned out due to the gas regulator having incorrect pressure settings and therfore not modulating properly and always burning at max rate hence the cutting out.

I had the Alpha people attend in the end. Thanks for all help.