In article I0Kyh.4275$yH3.3135@trndny07, "Marilyn & Bob" wrote:

OK. It's about 36' to the bottom of the top radiator about 39' to the top
where the bleeder valve is. So about 17 psi.

Yep. I think I'd go 18.

Now the question is how do I
get to that? We have a Filltrol diaphragm expansion tank and standard
expansion tank. I have not drained that standard tank in many years.

This has *nothing* to do with the expansion tank. The tank's only purpose is
to give the water some place to go when it expands due to being heated. Its
purpose is not to provide the initial pressure in the system.

m Ransley suggested bleeding the radiator with the water cold (but the
circulator pump on), is that a place to start?

No.

I've always bled it with the system on full blast.

That's fine when all you need to remove is a little bubble here and there.
Your problem, though, is that the system isn't full. You need to get it full.
And that means you shut it down completely. Boiler off. Circulator(s) off.
Everything off, and water cold. The fastest and easiest way of getting the
water cold is to run the circulator(s) while the boiler is off -- the
radiators will remove the heat from the water fairly quickly. Once the water
is cold, shut the circulators off.

Now, on to filling the system. It should be connected to the building's
domestic water supply through a pressure-reducing fill valve. That valve is
probably set at somewhere around 12 to 15 psi. You need to adjust it upward to
somewhere around 17 to 18 psi. (If the pressure setting is fixed and cannot be
adjusted, you need to replace it with a valve that can be adjusted.) One at a
time, open the bleed valves at the tops of the upper-floor radiators until
water comes out. Once you get water out of the bleed valve on every radiator,
the system is full. Turn it back on.

You'll probably still have some air in it. If your automatic air vents (you do
have some, right?) don't take care of it, then you'll need to do more
bleeding, this time with the system operational. Be careful you don't scald
yourself.


--
Regards,
Doug Miller (alphageek at milmac dot com)

It's time to throw all their damned tea in the harbor again.