Potterton performa 24 DHW prob

[Fuzzyduzzy]

I have a Potterton performa 24 bolier and there is a problem with the DHW. When the DHW is switched on the pin stays retracted in the pressure differential valve, hence the micro switch is not activated on so no DHW. There is a small water leak from the differential valve coming from where the pin itself is (rather than around the edges of the differential). I am a complete novice and not sure what to do, I have only found out the above by reading up on the internet.
Would I be right in assuming the problem is contained within the differential or could it be elesewhere in the boiler. I have opened up the differentail and can find no obvious damage but then again as I have not done this before not sure what a normal one should look like. If it is the differential should I replace the whole brass unit or can I replace the parts inside i.e the black rubber like seal and white plastic parts with pins on the end? What is the cost likely to be?
Any help greatly appreciated.

 

[Boilerman2]

You need a new Diaphragm, the kit will come with a new seal for where your leak is, it just screws in quite simple job to do, turn off electrical feed to boiler, turn off cold water inlet at boiler, open kitchen hot tap to release pressure, remove the bracket holding the micro switch to the housing, remove the two small impulse pipes from the diverter diaphragm housing, undo the hex screws around the housing and pull away from the valve. note how the exisiting diaphragm is fitted, and make sure the new one goes in exactly the same, refit in reverse order. Before refitting the micro switch, unscrew the old seal nut and repalce with the new one.
open cold inlet, and run hot tap, check for leaks.

Switch on electrical supply and run hot tap --all should be well

 

[Fuzzyduzzy]

Thank you very much Boilerman. Just one last question, where can I get such a kit from and what should I ask for? Sorry these are such baisic questions but as I said before I have not done this type of thing before.

 

[namsag]

do not undo both pipes just undo one at the front

 

[Boilerman2]

Thanks Namsag (so many boilers, so little time!!!!)

 

[Fuzzyduzzy]

Thak you for the posts, got the kit in the post, for just under a tenner, and fitted as instructed. Everything now works fine so all in all probabaly saved £50 odd labour costs.