central heating air lock

[eddg]

Can anybody help, i drained the central heating system and refilled it adding a cleaner, bled the radiators (downstairs 1st then upstairs as instructed). When i came to turn the heating back on the boiler fired up and cut out after a minute or so and did this a few times. Engineer came out and said there was an airlock in the system and rectified it. He was pretty evasive as to how he cured it when i asked him. I have to drain down the system and flush it a few times, what do i do if this happens again (apart from call british gas again!) thanks in advance for any help.

 

[Softus]

Where is the boiler?

Where is the pump?

Is it open vented?

Did you vent the pump?

What other vent points do you have in the system?

 

[eddg]

The boiler is in the garage, the pump is upstairs in the airing cupboard right next to the hot water tank. I am presuming it's open vented, there are 2 tanks in the loft, the F+E and the bigger water tank which i presume is for the hot water system. No i did not vent the pump (not sure how to either), there is a piece of pipe going straight up very near to the pump with a black plastic can on the top, it has a little red cap on the top of it. It does say open/closed at the bottom, would this be a vent? I apologise in advance, I am a good diy-er but i have never been involved with central heating systems in the past, guess i can learn now though!

 

[Softus]

If you unscrew the red cap a couple of turns, i.e. without removing it, do you get air, or water, or nothing?

 

[Softus]

A good and informative reply.

If you unscrew the red cap a couple of turns, i.e. without removing it, do you get air, or water, or nothing?

 

[eddg]

when i turn the black can to "open" then turn red cap air comes out

 

[Softus]

In that case, with the pump off, I would leave that red cap open until air stops coming out or water starts coming out.

 

[eddg]

lots of air came out, seems to have sorted it, thanks alot for your help it's much appreciated. Should i tighten the red cap back up, and should i leave the black can thing in open or closed position?

 

[Softus]

It sounds like an automatic vent, in which case leave both open so that it can vent automatically.

 

[eddg]

ok i will do. thank you very much for your help, i appreciate you taking the time to respond. When you have no hot water to bath the kids it's not a great situation!

 

[Softus]

You're welcome. And thanks for the simple act of thanks - it's more than a lot of people bother to give.

 

[eddg]

a small amount of water (like a trickle or so) came out whilst the boiler was on with the "can" in the open position and red cap open a couple of turns, should i close them both off?

 

[martinvanessa]

Hi
I am imressed by the helpful banter on this network, which I have now joined. My problem is undoubtedly down to ignorance.
Since we had a "burst" and everything was locked down for 24 hours I have silly problem.
All of the radiators on the ground and first floors are bled, on and hot......... the only radiator a floor higher won't bleed and is obviously cold. (no issues with it previously).
How do I get the hot water to go up there?
very many thanks