Air trapped in open vent system

[abrob1]

Hope someone can help me out..

I drained the system a few days ago to change a rad valve and alter some other pipework for a towel radiator.

I now have air trapped in the system on both sides:

- Two radiators don’t seem to heat up, all air has been bled from them.
- The boiler is making gurgling sounds when hot water demand is on, hot water IS heating up so it’s not completely locked out but more air is trapped in the cylinder coil.

It’s a Y plan with a pump and 3 way diverter valve. There is no automatic bleed valve in the airing cupboard and there’s a vent pipe going to the loft tank.

Total of 8 rads, 4 of which are downstairs and each rad downstairs has a drain off valve.

I’ve read the suggestions such as pushing mains water up the drain off valve which will push the air up to the vent pipe.

Also a suggestion is pushing mains in the loft down the vent pipe to push the air back to the tank.

I’ve also alread you can use a wet vac on the vent pipe to suck the air out.

How do I go about getting rid of the air lock and bleeding the air from the cylinder coil?

Any help appreciated to sort this before winter.

Thanks!

 

[danfre]

If your confident try undoing the connection on the cylinder where the flow enters, just slacken it off to see if air is trapped in there.
Open the the manual lever on the zone valve

 

[abrob1]

If your confident try undoing the connection on the cylinder where the flow enters, just slacken it off to see if air is trapped in there.
Open the the manual lever on the zone valve

Will this remove the air that’s stopping the two radiators from heating up?

Could I instead loosen the nut on the 3 port valve that goes to the cylinder instead?

 

[danfre]

Air can get trapped at the cylinder.
If you have a speed setting on the pump try changing up and down

 

[danfre]

Close down the rads that are working, turn on the heating it might push the air out

 

[abrob1]

Air can get trapped at the cylinder.
If you have a speed setting on the pump try changing up and down

How about setting the heating to both watwr and radiators, then maxing out the pump? Where will the air escape for me to bleed it?

 

[Razor900]

Best idea is to post a picture of the pipework around the cylinder

 

[dilalio]

You sure it's just air and not crap that has come down from the system draining?

 

[abrob1]

Best idea is to post a picture of the pipework around the cylinder

I’ve now added some pictures..

 

[abrob1]

You sure it's just air and not crap that has come down from the system draining?

Yeah pretty confident, there is still flow but just very noisy.

 

[Razor900]

Assuming the Airjec isn't blocked (round thing at the top of the pipework) there doesn't seem to be a reason there the system won't bleed.

Firstly turn everything off for a couple of hours and manually open the three port valve, (press and slide the black lever on the white box until it latches in place). Any air in the coil should find it's way out.

Then put just the heating on, turn the pump to max. Let the system run for a minute then pull the plug out of the pump for a few second then back in. Do this a few times and you should hear the air starting to move.

If after that it's just one or two rads that are cold turn the working ones off and try again.

 

[Johntheo5]

Arn't these Aerjecs prone to getting blocked up over time. The OPs seems 90deg orientated from this one but maybe still installed correctly?

 

[abrob1]

Assuming the Airjec isn't blocked (round thing at the top of the pipework) there doesn't seem to be a reason there the system won't bleed.

Firstly turn everything off for a couple of hours and manually open the three port valve, (press and slide the black lever on the white box until it latches in place). Any air in the coil should find it's way out.

Then put just the heating on, turn the pump to max. Let the system run for a minute then pull the plug out of the pump for a few second then back in. Do this a few times and you should hear the air starting to move.

If after that it's just one or two rads that are cold turn the working ones off and try again.

Thanks I’ll give this a go. If I was to run heating and hot water demand at the same time, shouldn’t this move the air around the system hopefully up the vent pipe?

 

[Moss5]

Check if there is a bleed screw on the pump impellor body. Should be bled with pump off.

 

[Johntheo5]

Thanks I’ll give this a go. If I was to run heating and hot water demand at the same time, shouldn’t this move the air around the system hopefully up the vent pipe?

Stating the obvious, presume the Feed&Expansion Cistern is "full" of water?.
Long Term, you should clean out/renew/modify that Aerjec, looking at your photo, the very top pipe should be the cold feed, the top middle right should be the Vent, the bottom right should be HW feed (boiler flow) in, the bottom left should be the feed out to the pump inlet. Some just throw that Aerjec out and install in its place, the Vent, then the cold feed (no more than 150mm from the Vent) then the pump.
You might show a photo of the pump front and give the make&model and what mode&setting its running on.