I've got a vented central heating system comprising of a Potterton Suprima 40 boiler, Grundfos Selectric pump and unvented HW cylinder.
Last week I lost heat to the downstairs radiators. Bleeding didnt fix this nor was their any air came out of them.
The F&E tank in the loft was pretty sludgy so I decided to drain down, fill with clean water, run for a couple of days before draining down at the weekend to refill with Fernox cleaner.
I had no issues draining the system down and got plenty of black water on the first drain and much cleaner water on the second drain.
Today when refilling I closed all lockshields and TRVS upstairs and filled and bled the downstairs rads first, closing them off at both ends once they were filled just to prevent any possible airlocks.
I then bled the upstairs radiators and proceeded to turn the system on after rebalancing all the lockshields both up and downstairs.
However the boiler must have an airlock somewhere because its boiling and then cutting out. I have bled air and water from the pipe on one of the flow/return pipes at the boiler and also bled air from the highest point in the system which is the top of the hot water cylinder.
The pump does sound noisy but there is water coming from the bleed screw when I open it.
I've spent about 2 hours searching the net and this forum for advice, so apologies if the answer is already here and I just cant find it.
Is there something else I can or should try to clear this airlock? I dont really want to have to drain down again as I'll lose all the fernox cleaner and at nearly £20 quid a bottle its a bit of a hard pill to swallow.
Is there a better way to refill this type of system?
Many Thanks,
Duncan
Last week I lost heat to the downstairs radiators. Bleeding didnt fix this nor was their any air came out of them.
The F&E tank in the loft was pretty sludgy so I decided to drain down, fill with clean water, run for a couple of days before draining down at the weekend to refill with Fernox cleaner.
I had no issues draining the system down and got plenty of black water on the first drain and much cleaner water on the second drain.
Today when refilling I closed all lockshields and TRVS upstairs and filled and bled the downstairs rads first, closing them off at both ends once they were filled just to prevent any possible airlocks.
I then bled the upstairs radiators and proceeded to turn the system on after rebalancing all the lockshields both up and downstairs.
However the boiler must have an airlock somewhere because its boiling and then cutting out. I have bled air and water from the pipe on one of the flow/return pipes at the boiler and also bled air from the highest point in the system which is the top of the hot water cylinder.
The pump does sound noisy but there is water coming from the bleed screw when I open it.
I've spent about 2 hours searching the net and this forum for advice, so apologies if the answer is already here and I just cant find it.
Is there something else I can or should try to clear this airlock? I dont really want to have to drain down again as I'll lose all the fernox cleaner and at nearly £20 quid a bottle its a bit of a hard pill to swallow.
Is there a better way to refill this type of system?
Many Thanks,
Duncan