In article JDLyh.2265$Yl3.1807@trndny09, "Marilyn & Bob" wrote:

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.

You don't have to drain the whole system -- not unless you don't have any
shutoff valves anywhere, that is. There should be shutoffs ahead of, and
behind, the circulator. Close those, so that the water in the rads and the
pipes doesn't drain back. Then drain the boiler.

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

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