Central Heating Airlock?

[rosss]

Hi

Ive just drained my central heating system but the water in the expansion tank hasnt drianed. All the rads have drained but, because of this possible airlock, I cant now seem to fill the system again.

I guess there must be an airlock stoppng the water in the expansion tank flowing into the rest of the heating system.

Is there an easy way to remove this air, or do I need to get a plumber in?!

thanks

ross

 

[kevplumb]

your cold feed is blocked IMHO

 

[rosss]

is there any way to check this myself?

 

[kevplumb]

you already have mate
if the system drains and the tank dont it aint going nowhere

now scuse me i have a fight on with a bottle

 

[rosss]

Ive rechecked the plumbing and its a bit odd. The cold water feed pipe from the attic is plumbed in to the boiler (on the second floor) but it comes up from the floorboards on the second floor, rather than down through the ceiling/attic.

Surely this up pipe could be affecting the draining of the expansion tank?

Would it be possible to either CAREFULLY fill the system from the mains via a hosepipe to the feed pipe in the attic, or alternatively the draincock on the ground floor?

Any advice would be greatly appreciated!
thanks

 

[ChrisR]

Yes there are loads of options like that. I put the mains down the feed pipe to try to force any movable gunk up through the vent pipe. But you may find the feed pipe is SOLID with rusty scale near where it joins the system.
Do a search on "feed pipe"

 

[Agile]

Its best to deal with the problem while the system is drained. The blockage is likely to be where the feed pipe joins the system.

A temporary solution is to fill the system from the vent pipe but that will not solve the actual problem which is the blockage.

Tony Glazier

 

[idealmaster]

you can check your cold feed by using a magnet as copper isnt metallic where the mag sticks chances are thats where your blockage is.. I have found that using a foot pump attacked too the cold feed is moe effective than a hose mains pressure.1-3.5 bar.....