Expansion tank not emptying

25 Mar 2007
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United Kingdom
Hi. Need help.

I have just draining my C/H system, all water is drained from rads, have opened all air bleed valve and am sure all water is gone. The problem I have the small tank in the loft (expansion tank) will not empty. I have tied up the ball valve so I known water is not getting in. But what is there will not drain.


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the cold feed is probably blocked, which means your gonna have trouble re-filling the system.
99/100 it will be blocked where it 't's ' into the heating pipe work. Cut out this pipe work and replace ;)
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follow the pipe from the bottom of tank into cly cuboard where it goes into bigger pipework{22mm} put a bung or plastic bag in tank 2 stop water from small tank cut pipework near tee bucket handy clean pipewok going into tee with driver put 15mm com cuplin on remove bung from loft happy days my son:cool:
When you replace the Tee, use a compression fitting not a soldered one, so that next time it happens you won't need to cut it.

Also, buy yourself a chemical cleaner so you can clean out some of the sediment that has caused the blockage, and when refilling after the clean and flush, use a corrosion inhibitor to reduce future corrosion.

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