Thermostat controlling White-Rodgers zone-a-flow water valve not working well


We have a Sears gas boiler, which supplies 4 zones of heating in the house through W-R zone-a-flow valves . We are only concerned with 3 here, as one is deliberately turned off.
We have well controlled thermostatic heat in 2 of the 3 zones, but we did not have any heat in the garage, which has its own zone. Yikes -- with 10-yr record low temps here, we had to save the pipes!! The thermostat in the garage was a bit beaten up, but no matter how I manipulated the dial, the heat did not come on. I had the good sense to check the White-Rodgers zone-a-flow water valves, and discovered that, while the functioning zones' valves were open, the garage zone valve was closed, so I manually opened it. Voila -- heat in the garage! We are saved from doom (so far). The once frigid garage is now recording temps of 50-52 degrees -- if that gets us over this Siberian cold blast, fine. But I was kinda hoping to bring the temp down to 40-45 degrees, or so.
Any way to get the thermostat to put out any temperature but 50 degrees? ANy idea why the W-R zone-a-flow valve did not open in response to the thermostat, and had to be operated manually?
All the thermostats in the house are W-R 125-202 -- clearly an ancient mode. I replaced the beaten up one with one I knew worked fine (from the zone we are no longer heating), but the darned thing does not control temperature any better than the beaten up one.
Clearly, the easy course is just to ignore the problem until the Siberian front retreats, and take it up the wazoo for paying to heat a poorly insulated garage to 52 degrees.
I checked for loose wiring on thermostat and zone-a-flow -- and everything seems to be nice and tight.
Will upgrading to a more modern thermostat help? Or is it a deeper wiring problem? Could it possibly be the garage zone-a-flow valve malfunction (I checked the wiring and everything eems tight)?
Advice, O Home Repair Gurus, I humbly request.
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i tried turning off the radiators in a stairwell zone to save money one winter. when one froze, broke, and leaked it sprayed water. winter is one season too late to prepare for winter. some systems are not set up for what you are attempting. incompletely draining a zone in winter will lead to damaging any low points of that zone that will freeze and break.
On Feb 5, 2:43 am, snipped-for-privacy@yahoo.com wrote:

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snipped-for-privacy@yahoo.com wrote: [snip]

Clearly the valve itself is OK, since you could open it manually, so the possibilities fall into five categories:
1) defective thermostat. 2) defective zone valve actuator. 3) defective wiring between them. 4) defective wiring supplying power to the actuator. 5) defective power transformer supplying power to the actuator.

That would appear to rule out #1 above.

Absolutely. May not be the best course :-) but it certainly is the easiest.

That doesn't rule out a break somewhere in between, though.

No, maybe, and maybe, respectively. You could also have a failed 24V transformer that isn't supplying any (or enough) power to the actuator.

What model of White-Rodgers zone valve is it? If it's not completely ancient, you can find information about it on their web site at
http://www.white-rodgers.com/wrdhom/common/ptech/hydronic/hydronic_02.htm
Click the link for the zone valve you have, then find and click the Troubleshooting link, and you'll get a short list of diagnostics that will help you find where the problem is.
--
Regards,
Doug Miller (alphageek at milmac dot com)
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It would appear that the powerhead of the zone valve is not getting 24 volts needed to open,or the powerhead is bad. It's likely that all three valves are powered from the same transformer, so it could be wiring , or thermostat, or zone valve. I'm not familiar with this valve, it could have two, three, or four wires,or terminals attached to it. If you can see which two wires are attached to the valves motor, and check to see if there is 24 volts across those two wires with the thermostat set high. You can cross check with a working valve, to be sure you're on the correct wires. This can at least verify the valve's power head. The thermostat is probably the least likely culprit and to verify it remove the wires attached to R or RH and W, and twist them together. That should energize the valve, or at least send 24 volts to it

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On Feb 5, 1:43 am, snipped-for-privacy@yahoo.com wrote:

On the powered zone valves in my house, the circulator pump does not come on until a small switch on the zone valve is activated, indicating the valve is fully open.
One valve motor was getting stiff, and it would't quite go far enough to hit the switch. You might have a similar arrangement/problem.
Dave
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