Hi all,
Got a nightmare situation with a central heating system I recently adopted. It's an open vent system with a combined F&E pipe, with a Worcester greenstar danesmoor 18/25 oil boiler. Covers 10 radiators mostly large double panels, some towel rails and smaller rads too, as well as an indirect gravity fed HW cylinder. 2 rads upstairs the other 8 downstairs. F&E tank is in upstairs attic above highest rad. Some 10mm microbore branches, the rest is 15mm branches from a central-ish point. It's never worked right since day 1, lots of gurgling in pipes and boiler would often cut out/lock out due to air inside it so clearly the system had air in it. Anyway the time has come to sort it out, long story short the system was recently drained down about halfway ie. Upstairs rads and underfloor piping only was drained plus one downstairs rad.
Upon trying to refill, no water came through from the F&E tank. Removed top plug in the towel rad and tried using a wet vac to suck water through - no luck. Tried using and pulsing the CH pump to suck water through, nothing. Eventually managed to refill the upstairs rads by shooting mains pressure water into the system through the drain off, however there's still airlocks in some piping as we can hear it and the boiler keeps cutting out due to air inside it. All the rads in the house bleed water not air, so they appear full. Pump (DAB evosta 3) does run but at only 4-8W when set to maximum speed (it self regulates) and it sometimes shuts off with error code 'running dry'. Spent literally all day playing with mains water pressure, sucking, pulsing the pump, draining more water through the system etc. Whatever air locks exist they will not go.
F&E combined pipe is definitely not blocked, it connects to the system just before the pump so the pump should be pulling water through, but isn't. CH and HW valves been on fill/vent/open setting throughout. We can also see and hear air bubbles going up through the pipe into the f&e tank so it appears to function like it should. Pump assumed to be operating correctly as it was replaced recently since the old one was knackered.
Would really appreciate any advice, I'm slightly losing my mind over this as I can't see any logical reason why the airlocks can't be removed or even found especially since all the rads are full of water!
Thanks, and sorry for the long post, but hope it explains the system reasonably well.
Got a nightmare situation with a central heating system I recently adopted. It's an open vent system with a combined F&E pipe, with a Worcester greenstar danesmoor 18/25 oil boiler. Covers 10 radiators mostly large double panels, some towel rails and smaller rads too, as well as an indirect gravity fed HW cylinder. 2 rads upstairs the other 8 downstairs. F&E tank is in upstairs attic above highest rad. Some 10mm microbore branches, the rest is 15mm branches from a central-ish point. It's never worked right since day 1, lots of gurgling in pipes and boiler would often cut out/lock out due to air inside it so clearly the system had air in it. Anyway the time has come to sort it out, long story short the system was recently drained down about halfway ie. Upstairs rads and underfloor piping only was drained plus one downstairs rad.
Upon trying to refill, no water came through from the F&E tank. Removed top plug in the towel rad and tried using a wet vac to suck water through - no luck. Tried using and pulsing the CH pump to suck water through, nothing. Eventually managed to refill the upstairs rads by shooting mains pressure water into the system through the drain off, however there's still airlocks in some piping as we can hear it and the boiler keeps cutting out due to air inside it. All the rads in the house bleed water not air, so they appear full. Pump (DAB evosta 3) does run but at only 4-8W when set to maximum speed (it self regulates) and it sometimes shuts off with error code 'running dry'. Spent literally all day playing with mains water pressure, sucking, pulsing the pump, draining more water through the system etc. Whatever air locks exist they will not go.
F&E combined pipe is definitely not blocked, it connects to the system just before the pump so the pump should be pulling water through, but isn't. CH and HW valves been on fill/vent/open setting throughout. We can also see and hear air bubbles going up through the pipe into the f&e tank so it appears to function like it should. Pump assumed to be operating correctly as it was replaced recently since the old one was knackered.
Would really appreciate any advice, I'm slightly losing my mind over this as I can't see any logical reason why the airlocks can't be removed or even found especially since all the rads are full of water!
Thanks, and sorry for the long post, but hope it explains the system reasonably well.
