On Sat, 14 Feb 2004 21:54:52 -0000, "JohnB"
wrote:

Thanks.

This is going to be interesting! Hopefully that will save me the cost of a
13 litre expansion tank. Costly no doubt.

John


Is it integral in the boiler, or separate?

You can get separate ones of that size for about £15 so it's not too
horrendous.





"Andy Hall" wrote in message
.. .
On Sat, 14 Feb 2004 18:22:06 -0000, "JohnB"
wrote:

Very very useful FAQ

My sealed system seems to have partially failed, ie I can keep it from
going
over 3 bar by limiting the temp to 75C and keeping min pressure at about
0.4
bar.

I presume that the air will have leaked and needs pumping rather than
the
diaphram holed - or am I just being hopeful!!

John



Try turning off the heating and remove the dust cap from the Schrader
valve on the expansion vessel. Release the pressure carefully as you
would to let a car tyre down.

If water comes out then you know the answer to your question and a new
vessel is needed. Otherwise, release the water pressure on the heating
circuit completely and then precharge the expansion vessel with a
suitable supply of compressed air or a tyre inflator. Finally
pressurise the water side again.

If you do have to replace the vessel, they come precharged with
nitrogen


.andy

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..andy

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