OK, within minutes of actually posting my wife called to tell me the
heat started working, thanks for all the good karma or whatever it
was.
Anyway, to fill in the blanks, not that it matters much now. All zones
have their own circulators. Didn't do any testing with the thermostat
it was still controlling the heat (when I turned it up the circulator
would come on and likewise when I dropped it, it would turn off).
Thanks for the heads up on the failing valves, I'll keep that in mind
for the future. Sorry for not providing enough info. I was 'spoilt'
with a simple hot air system in my previous house. This one is a total
rats nest of pipes going every which way, that I'm still getting to
grips with. Although it's a heck of a lot better than a hot air system
IMHO


Ian

On Feb 12, 1:23 pm, "Pete C." wrote:
Doug Miller wrote:

In article . com, "Ian" wrote:
Last week woke up and the downstairs main heating zone was not
heating. A second zone feading just 1 room was working and floors 2 &
3 (separate zones) had heat also.
[snip]

The circulator is running and I'm able to bleed all radiators, can the
pipes possibly still be frozen?

It's hard to see how.

At night it's been down to 5 degrees.
We're on concrete slab, so no basement but I have an electric radiator
sitting on the concrete in the general area between the original house
and the addition where the pipes run underground (in the middle of
some rennovation also).

Any ideas on what else to try would be much appreciated.

Defective thermostat, defective zone valve, defective wiring, defective
circulator relay, major water leak -- that's about it. :-)

You haven't posted enough information to narrow it down any better than that.
How many circulators in the system? Just one, or does this zone have its own,
dedicated circulator? Presumably, there's a zone valve somewhere, to control
water flow into the zone -- what type? Does it work? Have you tried swapping a
thermostat in from one of the zones that has heat? Have you used a voltmeter
to verify proper voltages at the thermostat, zone valve, and circulator relay?

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

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

Second on the zone valve. They seem to have a fairly high failure rate
and should be among the first few things to check. They usually have a
manual override lever on them as well so you can still get them opened
when they fail.- Hide quoted text -

- Show quoted text -