"If the system was installed correctly, there should never be any air in
the
system." What part of that statement don't you understand?

Heatman, you obviously don't know old heating systems and radiators.
You did not read the original post, nor my definitive answer and do not
understand the concept of what faxemail123 is trying to do. Since i
answered his question to his satisfaction, I reply yet again to educate
you a bit more only because you are a helpful though argumentative
person. What parts don't you understand?

A hot water system has air in the expansion tank. It has to be there.
If the expansion tank becomes water logged, the system will not
function properly

A heating system gets air in it from the expansion tank, expansion and
contraction of the water as it heats (air is released), air bubbles
introduced in make-up water and water originally used to fill system.
It doesn't have to have a leak. Air is introduced naturally. Modern
baseboard heating systems don't typically need to be bled because they
are basically just a water pipe with fins. There is no place for air to
accumulate. Radiators have a very large space for air to accumulate. As
such, radiators must be bled periodically and as such should have
valves in the top to let the air out. They are commonly known as
bleeders. They are manually opened and closed with a "radiator key" to
let air out. Self bleeders are valves which allow air out but not
water. They typically were not used because of their additional expense
(5 to 7 times as much as a manual valve) and because they frequently
stopped working and had to be replaced.

"Okay, this has gone too far for me to attempt to daignose over the
'net. I
thnk you need to get someone into your house that knows hydronic
systems."

He never had a problem to diagnose. Read the title of the post.

"If he needs to regulate heat output, get outdoor reset for the
system.
It'll save money too."

He doesn't need to regulate the heat output of the system, only
specific rooms,specific radiators, therefore resets for the system
aren't the answer.


Think about it. Sewer lines are cast iron. Radiators are cast iron.
For
all intents and purposes, they don't corrode.
[/color]
Yes they do.

O.K. They corrode to the extent of getting a rusty coating on them.
Unless the cast iton is defective to begin with, they will not
deteriorate to a point where servicability is affected. The cast iron
sewer and cast iron radiators in my 90 year old house show no signs of
deteriorization. Nor has any of the cast iron I've seen in some 5,000
houses been rendered unservicable. "For all intents and purposes"

Faxemail, glad I could help.

Heatman, it's been interesting. Keep up the good work


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