How can I sort out an airlock in a customer's heating system?

[The Plumber Guy]

Usually I back fill the system with water from an outside tap on a drain valve (if the feed & expansion tank isn't doing its job) but the drain valves are useless and let all the water out so now I'm stuck! Does anyone have any simple suggestions as to how to get this airlock out please?

 

[Paulplumb]

Get a teaspoon and tap gently on the cylinder for an hour. Works every time.

 

[Gray0689]

Connect mains from f&e tank to vent

 

[kay-jay]

yep ...like gray says connect the mains to the open vent.
use 2 flexis joined together with the compressions at opposite ends (1x15mm & 1x22)
connect one end in place of the ball valve in the f+e and the other end to the open vent and run the mains through it. this should blow the airlock out.

alternatively

find the smallest downstairs rad close the valves (note the turns required for lockshield)
crack the nuts open a touch lift the rad off brackets and pull away from the wall
place the top of the rad on the floor rad will be upside down and slope upwards to the valve connections and water will be below the valves ensuring only minimal leaking.
undo valve nuts fully and move rad to a safe position
standard hosepipe connectors will screw onto rad valve, open valve and drain down then replace rad and refill system

KJ

 

[The Plumber Guy]

Sorry - I responded to the wrong post - but thank you for yours! Gotta get used to this forum

Fascinating! You do mean the hot water cylinder don't you? I've no idea how that would work! Thanks by the way.​

 

[kay-jay]

well your original post asked about an airlock on the heating system. so my reply was about the heating system.
therefore i mean the f+e tank not the cylinder.
connecting the mains to the open vent pipe forces pressured water back through the system and will force the airlock back into th f+e tank via the feed pipe.

it is possible to remove an airlock in the hot water side in the same way by connecting the cold tap (mains fed) to the hot water tap

hope this helps

KJ

just to clarify

in essence all that is being done is creating a filling loop which operates through the vent pipe instead of the feed pipe. the feed pipe then becomes the vent, the circuit is the same only in reverse. the mains pressure is sufficient to force the system water back around the circuit and up the feed pipe into the f+e tank blowing out the airlock. when bubbles rise from the feedpipe to the surface of the f+e tank the airlock is being released.

when done simply remove your flexi gizmo and reconnect the ballvalve to the mains

 

[The Plumber Guy]

Hi KJ,
Sorry- I do understand this way of doing things and it makes perfect sense. I don't know if you saw but there was a reply about tapping the cylinder for an hour with a teaspoon (which I thought might be taking the mick but I think it's for real!) and that's the one I was asking about. I only joined yesterday so I' trying to get used to the forum. Very interesting so far though.

One final question - when you'r using the f&e method you describe I'm assuming the 3-port valve needs to be moved into the open position? Thanks again.

 

[kay-jay]

aah sorry crossed wires eh?

err the spoon thing....well it might be for real but do you want to waste an hour finding out? i would only consider this as a very last resort.
wouldn't the effectiveness of this method be dependent upon where in the system the air was trapped?

i too would be interested to know if it is for real?

oh and yes open the mv's manually to allow the circuit to flow

KJ

 

[Scottley]

for the hour you spend with a spoon you could have blown it through with kay jay's method. (Nice avatar btw kj)

Plumber guy what area are you from?

 

[The Plumber Guy]

It is a nice avatar isn't it? I'm more for blowing through than tapping with a spoon but hey, whatever works. I'm from Leighton Buzzard in Bedfordshire. I've only just qualified as a plumber and this job is for a mate so I thought I was starting easily but no such luck! Cheers.

 

[Puddle]

Get a teaspoon and tap gently on the cylinder for an hour. Works every time.

The spoon thing does work,have to use a table spoon and pull your trousers down around your ankles and whistle dixie,may sound strange doing that for a hour but last time I did it,air lock cleared within 50 mins but in fairness have seen it take a lot,lot longer !!

some would say it cleared by it,s self over a period of time with pump running but I have no time for such scepticism,if something works,I stick with the system !!

 

[Gray0689]

The spoon thing does work,have to use a table spoon and pull your trousers down around your ankles and whistle dixie,may sound strange doing that for a hour but last time I did it,air lock cleared within 50 mins but in fairness have seen it take a lot,lot longer !!

some would say it cleared by it,s self over a period of time with pump running but I have no time for such scepticism,if something works,I stick with the system !!

Puddle is right it does work I saw it funny thing was when I saw it I had on this funny White jacket that had straps on arms lol

 

[Scottley]

This will freak you out then, its not the job in Lime Grove is it?? lol

 

[The Plumber Guy]

I just wanted to say thanks to all who posted their help about the airlock in the central heating system - I've sorted it using the F&E method. I did offer to drop my shorts and tap on the cylinder for an hour but the customer strangely declined. Cheers all!

 

[Rodreguez]

i'm from leighton buzzard aswell mate. i've had some tough airlocks, 1 i tried to boil out, blow mains everywhere and didn't work so in the end i turned the pump round to pump the wrong way and it got the air straight out! Then turned pump back round and job done but this mite not work 4 you. defo best method is to blow mains through open vent!