Help! Feed & Expansion tank won't empty!

Hi, I have a standard open-vented system with an old back boiler (behind a fireplace downstairs).

I was trying to drain the system today to get several radiators off for decorating.

so.. I tied up the float arm in the expansion tank and drained from the drain valve at the lowest point in the house - I allowed to re-fill a bit to get the dirty water out. Now the water won't drain from the expansion tap even when the drain valve is open and all bleed valves are open.

In the end I re-filled the system from the drain valve downstairs by blocking vent pipe but no air seemed to enter the expansion tank via the feed pipes that I could tell - didn't want to leave the pressure on too long as was worried about how much pressure the boiler could handle.

The system is working now (ie Rads and hot water) but I am concerned the expansion tank is not topping up the system due to a block - Just noticed the tank overflow was going for a bit (had the system on for a couple hours)

any ideas what the problem could be/how to fix it?

Thanks

wrighty208 said:

I was trying to drain the system today to get several radiators off for decorating.

Click to expand...

No need to drain, just turn the valves off at each end of the radiator, unscrew the nuts which connect to the radiator (have something at hand to catch the water) and take radiator off the wall.

Job done.

Expertboy said:

wrighty208 said:

I was trying to drain the system today to get several radiators off for decorating.

Click to expand...

No need to drain, just turn the valves off at each end of the radiator, unscrew the nuts which connect to the radiator (have something at hand to catch the water) and take radiator off the wall.

Job done.

Click to expand...

Thanks but that's a bit tricky as there are boxed in pipes below the radiator (bathroom taps) so it's hard without making a mess of the carpet!

Also I want to remove several radiators in different rooms to decorate (just moved in) so figured it would be easier to drain the system - give it a bit of a clean out too.

I'm concerned that the expansion feed pipe may be blocked now though as the tank won't drain - even when opening the drain valve.

You have a blocked cold feed. Do a search on that - there is loads here on how to fix it.

EliteHeat said:

You have a blocked cold feed. Do a search on that - there is loads here on how to fix it.

Click to expand...

Cheers guys, you were right - the cold feed was blocked where it joint onto the main circuit (the T-Junction??).

All sorted now - runs freely through the system.