DHW Pressure Differential Valve leak

[chef]

Hi all, first post here, please be gentle

I have a two year old Potterton Performa 28i. About 6 months ago the CH differential valve sprung a leak where the pushrod exits the assembly and the microswitch attaches. A local plumber came round and sorted this for me, though it took him two attempts (both were charged for).

It looks like it's now the turn of the hot water valve to spring a leak, though this time it doesn't appear to be coming from the pushrod, the water appears to be dripping from the back of the valve assembly, either where it attaches to the manifold behind, or where the pressure pipe attaches. Could this just be a case of needing to re-seat the valve, or could this be something more sinister.

Anybody seen this before, or have any ideas what's likely to have caused it? Any help would be appreciated.

Thanks

 

[ChrisR]

The parts are all on http://www.partsarena.com/baxi/

For the ones you mean, you only have to turn off the CW supply under the boiler and drain.
Put new O rings/gland seals in with a smear of silicone grease. You may as well change the dhw diaphragm while you're in there if the parts come in a pack. The HW pushrod gland DOES leak, so ditto. Or just change the leaky bits and keep the other parts until you need them, which you WILL sooner or later

 

[chef]

Chris thanks for the reply, will give a supplier a ring and see what a pack contains, hopefully I'll just be able to get the seals rather than all the other bits. I have a spare diaphragm from the last repair, so may change that whilst I'm at it.

Recently the hot water has needed to be turned on very high to get the boiler to kick in, does this sound like a suitable culprit for such behaviour?