AIR LOCK

[kofi2003uk]

i have a radiator that stays cold. have tried to bleed it but water comes out straight away. i believe there is an air lock in the pipe leading to the rad.
will i get rid of the air lock by removing the union lock, letting out some water and putting the union lock back on.
if so any tricks i need to know before starting this job.

thanks

 

[Breesey]

Close all the other rads and run the heating. Speed the pump up too if you like. Turn heating off, bleed rad. Put the heating back on ...

That should force an air lock out.

 

[kofi2003uk]

thanks Breesey. i have done that already. the radiator wormed up. however when i tried to bleed it , water came out straight away.checked the other rads. no air in them.
however when i turned all the radiators on the problem came back again.
how long do i have to run the heating with all the other radiators turned off to get rid of the air lock?
thanks

 

[hi-spec plumbing heating]

>however when i turned all the radiators on the problem came back again.

will do if you don't balance the system

 

[Breesey]

Is the cold rad furthest from the boiler?

 

[kofi2003uk]

it was added to the sytem after an extension.this was about three years ago and its bben working fine till now. i dont think its the farthest from the boiler.

 

[Breesey]

You need to balance the system properly though. Identify the order that the rads come after the boiler and balance accordingly.

 

[JohnD]

It probably isn't an air lock. You might have sediment blockage. what colour is the water that comes out when you bleed? Do you know if it was cleaned and inhibited when the alteration was done?

For balancing see http://www.diydata.com/projects/centralheating/balancing/radiator_balancing.php

 

[kofi2003uk]

water is clean. infact very clean as it was drained about two months ago.fernox added.

 

[kofi2003uk]

thanks guys. shut all the rads off except offending one for about 30 min.shut down heating and bled the rad. bingo. thanks very much to everyone.