Marilyn & Bob wrote:

"Doug Miller" wrote in message
. net...

In article haLyh.4281$yH3.737@trndny07, "Marilyn & Bob"
wrote:

Doug & Jim,

Thanks again for your help.

I think I now understand our communication problem about the expansion
tank.
The Fill-trol expansion tank see: http://www.amtrol.com/pdf/filltrol.pdf
also serves a pressure regulator.

Aha! Yes, that explains a lot. Clever mechanism, isn't it?


I have the one combines with the air
purger. Yes, I know that the second (standard type) expansion tank that
is
parallel in the system is irrelevant here. So, based on your advice, it
looks like to adjust this, I have to get an air pump and raise the air
pressure in the tank to about 18 lbs. from the current 12 lbs.

Correct.


The only
thing that I still need to understand is what is meant by the caution that
"The Fill-trol must be free of water when changing the air charge." It's
not clear to me how to achieve this "free of water" condition. I can
e-mail
the manufacturer to find out what do if it is not obvious to either of
you.

If you shut off the water feeding the FillTrol, then shut off and drain
the
boiler, that ought to empty the tank. Then you can adjust the tank
pressure.
Close the boiler drain, and open the shutoff.


OK. Since it means draining the system, it can wait until the spring. (It
takes at least five or six hours to drain and refill the system. Huge
radiators, and since we have no floor drain (sewer lateral is above cellar
floor height), draining has through a hose. Thanks again for you advice.


Adjust the FillTrol regulator to give the required system pressure
when Cold. This has nothing to do with the air pressure in the
bladder; this adjusts the pressure of city water connection to boiler.

Do NOT drain the boiler. Admitting fresh water to the boiler
only results in increased corrosion.

If it is possible to drain the old exp tank without draining the
whole system, that may help. Do it *before* adjusting the FillTrol.

Jim