CH air lock????

[andybanner]

I am changing the bathroom rad for a towel rad, so have to move the pipework.
I partially drained the system so i could put in 2 isolating valves to connect the new rads to later. Turned the valve back on under the feed tank to fill the pipes back up.
But now none of the rads in the house will get warm.I have bled all of them until water runs.
Is it poss. that there is an air lock someware in the pipework?
How do i get rid of it if there is?
The wife's COLD so you can imagine how much earache im getting!
PLEASE HELP!

 

[dmccormick]

Possibly an air lock on the boiler - I had very similar problem last night. Was solved by loosening the screw on the CH pump on the boiler to bleed it.

 

[andybanner]

Not lived here long.
And not come across pump yet.
any ideas were it may be?

 

[andybanner]

Found the pump.
Undid the screw and water flowed!
Any more ideas?????
Found a plumbers note-
pump replaced and system flushed Oct.2002

 

[dmccormick]

Is the pump running (feel the casing to check for vibration). Does the boiler light up.

 

[andybanner]

yes pumps running and boiler fires up

 

[felix]

Point one: Did I read correctly? You opened a valve UNDER the feed tank to fill the pipes up? That's a funny place to have a valve. That pipe is your expansion pipe for the heating circuit and should always be open. Having said that, as long as it is open it won't give any trouble.

Point two: Where exactly did you put those isolating valves. Are they on open ended branch pipes which will eventually go to a new radiator? Or are they in line - perhaps in the pipes leading directly to and from the boiler? In the latter case they will have to be open or else all your radiators will stay cold despite the best efforts of the pump and boiler.

So now we've eliminated anything stupid, the pump is running and the boiler is lit, perhaps you really do have an airlock. There's no simple answer to airlocks because it all depends on the way the pipes run. I've had to shift a few in the past and have usually managed it by running the pump with only one radiator open at a time. There is one thing to watch out for. If you have a fully pumped heating/hot water system with a three port valve, you have to get the valve into the 'heating only' position. If you don't do this, the water will take the easy route through the hot water cylinder's coil and the air in the radiator pipes will stay put. Set your controller for heating only.

 

[andybanner]

The tap is UNDER the expansion tank, on the pipe that comes from under the tank and not the water fill pipe.
The valves are on open ended pipes which will go to a new rad.
The heating still worked when i just removed the rad. It was when i had to drain to cut off existing valves and put on the isolaters ready for the new rads that all the problems begun.
I will turn off all the rads and try to get one working at a time.
If i don't scratch a hole in my head first!


Thanks for the info

 

[andybanner]

p.s
Ihaven't got a heating only possition.

CH & Water or Water only

 

[doitall]

could try turning one valve off on each rad and venting, then swop them around by opening the other end and closing the first end and venting again.