Kathy wrote:

Either you have a bad zone valve or your
expansion tank is bad.


Tell me about this expansion tank thing. Am I ever
supposed to empty it? It has a fitting on it for a
garden hose.

alt.hvac added (help us out here pros!)

Hey you guys, that was a lady asking, tell us some more!

I've already read quite a bit of misinformation in this thread,
as I'm having the same problem with my Grundfos 15-42 F.

It's darn cold, and I don't know if the pipes are froze,
or if there is a blockage, or and air lock, or the pump
is just gone. There is no vent hole, I've got no backup
valves, the flow control valves won't turn manually,
some kind of ancient TACO crap, frozen solid.

The upstairs zone is going like gangbusters with
the big B&G pump, but the downstairs Grundfos
zone just quit, no flow, no hot pipes past the flow
control valve, registers dead cold. The pump is running
and I went out and got a little bleeder key, but
where the hell do I start? I want to do it right.

If I have to take the pump out, I'll have to drain
the system, so I may as well put in an air
scoop, backup valves etc, but maybe it could
be something simple, like that air tank.

Questions.

If one zone is working, do I forget the air tank?

How often do those old check valves freeze up?
I notice there is a plug on the bottom, can I just
remove that and clear it of any crap in there?

Help us out pros!

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