Hi have an oil boiler with 6" twinwall flu. I wish to have a mains Gas boiler fitted do i need a new flue or can a 5" liner be put in the exsisting flu.
Can someone help my velaire pj 90/110 old boiler has decided to keep it self warm even when the HW & CH controls are set to off both valves are closing and the pump not running boiler red light stays on. i have to switch off at the main supply when not in use
