Alpha 240X DHW problem

[dillon100]

Problem with an Alpha 240X DHW system.

The DHW supply is intermittent. Sometimes I get hot water, sometimes luke warm but generally it is fairly variable. I have visually observed the operation of the diverter valve 'plungers pins' and microswitches and everything seems to work as expected from reading the maintenance manual. When the DHW tap is turned on both pins come out and operate both microswitches. Most posts seem to suggest a diverter valve problem - possibly that the actual valve is not operting correctly internally even though the external signs look good. Other posts suggest problems with the DHW heat exchanger. A plumber has advised a new diverter valve after the briefest of 'inspections' - don't think he even took the covers off the boiler.

Now the thing the really confuses me is that even when I get really hot water out of the tap the DHW outlet from the boiler never gets above luke warm and it is only the main larger CH outlet that gets hot. That suggests that the hot taps are fed from the CH circuit as well as or instead of the DHW outlet. That sounds strange to me but maybe I am missing the point somewhere.

I want to be confident that if I spend the £350 quoted to get the diverter valve replaced that it will fix the problem but it seems there may be other issues here as well. I don't know the history of this system so I can't say whether it has ever worked properly or has always been this way. Apparently it is about 12 years old.

Can anyone shed any light on this?

 

[Agile]

If the diverter valve pin comes out then the switch is often intermittent. The effect of that is that the pump does not come on.

The rear manifold part of the diverter valve does not always follow the front part and sends heat to the rads instead of the hot water.

We charge about £200 to replace a diverter valve inclusive so that £350 seems a little on the high side. BG and some of the utility companies do fixed price repairs too.

Tony

 

[45yearsagasman]

The kits for these valves are near £55 and is a perfectly good repair.
Replacing the whole valve is unnecessary. It's only the internals that require attention. £350 is extortionate. The heat exchanger can be checked at the same time. Diverter is the 1st thing to fix.

 

[Agile]

I have tried repairing these and including boiling in citric acid to remove the deposits but that does not effect a very long term repair.

So to provide the most cost effective repair for customers I now always replace the whole valve when the manifold section is sticking.

I expect the springs have become weak over time.

Tony Glazier