I have a Baxi boiler which is working for the hot water but is somewhat intermittent with the central heating - it appears if I have the thermostat on the copper cylinder for the hot water up to its maximum I have ramping hot water and occasional central heating - however if I turn the thermostat down on the cylinder my central heating seems to diminish
I am assuming you have a mid-position valve system because it sounds as if you have a doggy mid-position valve actuator. Most of these actuators can be changed without draining the system but others require a complete new valve.
My mid position valve died a months back. As a carpenter I have a few years experience with the basics of plumbing so I had a crack at fixing it.
I found that plumbers suppliers and DIY stores all charge a fortune for valves like this. Eventually I found a Honeywell mid position valve on e-bay that went for Â£12. I was well pleased as most previous quotes where between Â£60-80... :shock: :shock: :shock:
I drained down my system and turned off the power. Took the old leaky crusty one off and replaced it with its newer clone! Plenty of PTFE later and it works fine.
I reckon if i'd called out a plumber it woulda cost me well over Â£150.. Job done for less than Â£20!!!!