Air lock (I think)

[MANDATE]

Hi Masona !
I agree that shutting off the pump valve and capping the open vent would make a one way direction and if the blockage was in the cold water feed pipe it would/should/may clear it, but it does miss out a little bit of the circuit. Now it all depends where these 'cold water feed' and 'expansion/vent' pipes join the circuit and the position of the pump relative to them. And of course if the blockage is in the bit not covered. With the pump isolated there will be a area each side of the pump that would have no flow of water and if the blockage happened to be there, then it would be by-passed.
I gather the trade substitute the head of the circulating pump with a pump that can have the direction changed to stir up any sediment so it can be flushed out easily, this pump I would assume is also capable of adding extra water and if the vent is capped the cold water feed pipe if blocked will also be cleared.
Does this make sense? or am I missing something?

 

[MANDATE]

 

[MANDATE]

 

[boggit]

I have to join in! Having recently bought a basement flat, the potterton baxi combi boiler having only been installed last August, but rads and pipework older - everything fine but last rad cold. Pipe to the rad hot but return pipe cold. I think its on its own pipe run - no other rads from its loop. also furthest from boiler. All other rads fine except they can't be turned off as most stuck open. Have changed rad but worked partially for a day then nothing. Could be air lock? but if so why is pipe hot to rad and cold return?

 

[fulcrum]

AlanE

Now have all rads working but agree they now need balancing. Have one with a large cold spot at the bottom - sludge no doubt. Will buy a new boiler soon and and wait for a powerflush.

 

[masona]

Does this make sense? or am I missing something?

No, I agreed with you !

No need to write it 3 times though ( I has this problem too! )

Hey, how about see thru' pipe so we can see where the blockage is !

 

[MANDATE]

Hi Masona !
I must have thought I was in the Civil Service, everything done in triplicate. Don't know what happened, I thought I had three failed attempts to send the message.
I agree with the see through pipe, glass would be ideal!