Airlock in open vented system?!

[ISM]

I have Recently completed a radiator install on a Y plan, open vented system. Filled the system back up and vented all rads and hot water circuit and fired the system up. At first the boiler fired every minute or so and the flow off the boiler was red hot and the return luke warm. Rads up stairs luke warm and rads down stairs cold. The boiler obviousley should not be firing every minute or so from cold start.

The boiler is located in the garage on the other side of the house, so two long pipe runs from the boiler to the pump, 3 way valve, tank etc.

There are two drian offs in the garage coming off the flow and return (coming down from the garage celing) and no drain offs on the flow and return at the top of the boiler (again flow and return coming down from the ceiling).

I drain the system down again from the drain off's in the garage as that only drains off half the system. Soldered a drain off on the return at the top of the boiler and filled the system back up.

I used the drain off I fitted to vent the system on the return; this seemed to improve things with the rads upstairs hot and the rads down stairs luke warm and the boiler firing less often.

I believe the system will improve slightly as time goes by and the rads upstairs will need venting once it does, but I am back Tuesday night to try and improve things further and wonderd if anybody has any suggestions.

 

[folwlerg68]

have you tried venting your pump? turn silver plug with a large flat bladed screwdriver anti clockwise have a cloth handy, till you have got rid of any air.good look grant

 

[SimonJohns]

Any rad that is working. Turn trv off

Force the water around the system the way you want it to go. So that it forces the air to the non working rads

You will spend a while chasing it thou. Can take all day

 

[darren bastin]

Assume this is an open vented system and fully pumped. Fire the boiler on hot water only at first see if the pump clears the primaries of air , once the boiler is operating normally and not cycling , shut down the hot water and fire up the heating. Shut down the rads that get hot easiest ( Upstairs). If rads dont come up downstairs, shut them all off bar one. If that does not work , if you have a drain cock on the downstairs circuit/rad try pulling the air out via a hose through both legs of pipe work. If the system worked ok before and you have not messed around with the balancing , most likeley to be air.

 

[ISM]

Cheers Darren, sound and logical advice!

 

[buckley plumb]

had a bugger of one a few years ago i had to fill the system from drain off on a downstairs rad with a hose connected to an outside tap .if all fails you could try this but be careful .

ant

 

[Leo21]

All good ideas above, test the strength of the pump by removing silver centre screw. Insert a small screwdriver and try to stop the pump spinning. If it snatches the driver it's good. If you can stop it easily the pumps shot. Occasionally when you drain a system the pump hasn't got the power to clear the air.