Potterton Performa 24 no hot water

[VivekMarwaha]

Symptom:
The central heating works fine but hot water does not turn on. When I turn on the tap - after 5 seconds, there is hot water but only for a couple of seconds. After that, cold all the time. When I turn on the CH, the burner turns on but not when I turn on the hot water.

A brief history which may or may not help with dealing with my issue. Yesterday, the pressure was showing up at 2.2 and, unintentionally I raised it to 3 but still same problem. Then opened up the boiler, turned the red valve and reduced it down to 1. Still same problem although now I am having to keep the pressure valve slightly open as the pressure keeps dropping if I leave it closed.

Please give guidance. Cannot see any clear leaks. The only documentation I have is the manual in
http://www.potterton.co.uk/products/productDetails.php?type=consumer&idx=1096&cat=1
- so please refer to the diagram to help me resolve this issue.

Thanks a lot
Vivek

 

[gas4you]

Sounds like the diaphragm gone. This isn't in the manuals you posted.

Take the outer case off and bottom left is a big round brass assembly with 2 small pipe vertically off it.

In front of this, attached, is a microswitch, this is actuated bt a small pin that is pushed out by the diaphragm. Turn your hot tap on and check that this pin pops out.

If not then a new diaphragm is needed.