DIY Doctor UK DIY Forums

Hi there

I have a Potterton Puma 80 combi boiler. Over the last couple of days I have had an intermittent fault with the central heating where it has failed to come on at times. The hot water seems to be working OK but the CH has failed to kick in, both on timer and when flicking the switch across to constant. Any suggestions greatly appreciated.

Thanks, W

Could be faulty wax capsule, try selecting CH if doesn't come on. Isolate the electrical supply and run the hot tap - this allows cold water to run through the boiler and the wax capsule will shrink - try CH again does it work ?

Check for any dripping hot water taps (even the slightest drip), this can stop the CH from working on the Puma.


Htg

Thanks for you reply.

No CH again this morning - it seemed to be working again last night.

I have tried your suggestion of turning off the mains and running HW, but still no joy.

Water pressure in the system seems to be ok: 1.5 bar, which is where it should be. I even tried bleeding some of the rads yesterday and topping up the pressure, but it's made no lasting difference....