This customer called me up because they had no heating. Their hot water was ok, but none of their radiators were heating up. I found that the heating pump had failed, possibly because all three automatic air vents (AAV’s) were completely scaled up. The AAV’s make sure the boiler is full of water, and not air. The pump can’t pump air around the system and will burn out if it tries to.
I replaced all three AAV’s and fitted a new Wilo circulating pump on the heating side. Re-pressurised the boiler, tested everything, and the radiators are all heating up as they should be now 😉
If you need your oil boiler repaired, please give me a call. I may be able to help you solve the problem over the phone / via a video call where I can see the problem.