Mother of all airlocks??

[skylined_gtr]

Hi All

I'm always draining down my central heating system and refilling after fitting new rads here and there. It's always been a b*gger to get rid of the airlocks on this system so I'm kind of used to it.

This time I have been trying to get rid of an airlock for the past 2 days! It just won't go.... I assume it's an airlock as I can't think of anything else it can be. There's one rad in one of the rooms that is staying cold no matter what, it's full with water but stays cold. By the way, this isn't the rad I just fitted - that's in another room.

After fitting the new rad, I filled the system as normal, ran around the house and bled all the rads, switched the system on, had the usual airlock probs where the boiler stops after about 5 mins of firing as it's reached temperature but hasn't been able to pump the water round the house due to an airlock or two got rid of that (or so I thought) and the house seemed to be up to temperature - apart from this one rad.

My 'Auto Air Vent' started pushing water out of the top a little, only a drip at a time but looks like it has been doing that all night and so made the ceiling damp a little, thankfully not too much!

I have a pressurised system (1.2 bar cold) with a Grundfos pump if that helps any. Please help I am running out of ideas!

 

[kevplumb]

remove the rad and open the valve into a bucket

have the missus on the loop filling up

 

[skylined_gtr]

Thanks Kevplumb, is it ok to leave the AAV open so it keeps dripping or should I close it for now?

 

[shambolic]

Thanks Kevplumb, is it ok to leave the AAV open so it keeps dripping or should I close it for now?

You should clean/replace it as dirt inside has caused it to fail to seat properly

 

[gday2uk]

Why not try closing off all other rads and just running system with the cold rad open to try and shift it?

 

[kevplumb]

Why not try closing off all other rads and just running system with the cold rad open to try and shift it?

nut's i assumed the op had tryed that

 

[skylined_gtr]

Hi to both of you

I've managed to sort it though I'd like an explanation as to how this happened - I'm confused!

Missus is at work at the moment so could not remove the rad without some extra help... closed all the valves and tried to force the lock out through the rad already before posting up on here - didn't work.

BUT I felt the feed pipe on the rad, it was hot. Rad was cold. So I figured if the feed is hot it's got to be that the L/S valve is clogged/closed/something as it seemed like the water was not flowing through. Got my grips on it and opened it a touch - guess what? Works fine now! What the hell happened to that L/S? I hadn't touched it and it worked fine before doing this work. Could it have had a blockage or something? Returned it back to where it was and rad is still fine.

 

[bengasman]

Your pipes are full of shyte.

 

[advancedplumber]

lock shield valve posibilly wasn't opened enough

 

[bengasman]

lock shield valve posibilly wasn't opened enough

Probably would have noticed the cold rad a when it was minus 10, along the lines of:
What's that icicle doing on my nose?

 

[Soggy_weetabix]

If there wasnt any purists on here I would advise a good lug of fairly liquid. Never fails. BUT... I never use it.

I have not travelled over to Harpenden to bail a plumber out who had spent a day trying to clear an air lock, only for me to arrive and never put fairy liquid in and have it working in 25 minutes.

David