Potterton Performa 24 problem

[skitzee2k]

Hey guys, bit of an odd one.

Got home today to find that there is no hot water coming through my shower or sink upstairs. Seems the burner doesn't ignite on those things anymore, however if I turn my bath tap on, in the same room,instant hot water.

If I then turn the shower on, after running the hot bath tap for a few seconds, the shower stays warm...in other words I have to jump start my shower..
Any idea what could be causing this? It's almost as if boiler isn't even detecting that the shower/sink is asking for hot water.

Both the heating downstairs and upstairs works, bled the rad and while a tiny bit of air came out, not much. Had to fill up the system slightly to get to 0.5 bar at resting, but just seems odd why they have suddenly stopped working.

Another added bit of info, I have an aerating tap and shower head...which obviously have been working fine for a year or so...just seems the boiler has got really temperamental, no pun intended and if you don't turn the taps on all the way it doesn't bother to light...any ideas?

Any feedback, even if "nope, no ideas" appreciated, that way I will atleast know its not something blatantly obvious

 

[picasso]

seems to be a night for dhw diaphragms, have a look at the instructions on how to change it and your boiler pressure should be 1 bar cold.

 

[skitzee2k]

Thanks for the reply, so this would explain less water hungry outlets staying cold while the fasting flowing are hot?

 

[picasso]

yep as the diaphragm wears it takes more flow to get enough movement to operate the microswitch.