hi i have a potterton puma 80 combi boiler, the pressure light comes on after about 8 hours of intermittent use and needs re-filling and will then work for another 8 hours befor it needs re-filling again, anyone any ideas thanks

chris, February 2011

You have a leak on the system somewhere.
When using the heating, keep an eye on the pressure on the guage, if it rises significantly (towards or past the red point), the system will most likely be losing pressure through the prv, this would mean the expansion vessel needs recharging/replacing.

Carefree, February 2011