1 out of 3 zones no good


Old 10-30-04, 09:08 PM
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Question 1 out of 3 zones no good

I have an american standard gas furnace circa 1974. The house has three zones. The system is hot water base board. Two zones have honeywell 2 wire tstats and work fine. Third zone has sears programmable (only using R & W) tstat. This zone does not turn on. I swapped out tstats from other zone, results are same. I have 25VAC on first 2 tstats and 21 VAC on programmable tstat. The light on the programmable tstat no longer lights when the relay in the tstat actuates.

There is 25VAC on each of the 3 zone valves. Historically system has worked fine. Could it be the zone valve? Could it be in the wiring between the tstat and the furnace? Any help would be appreciated.
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Old 10-31-04, 05:00 AM
Join Date: Dec 1999
Location: Northeastern NC On The Albemarle Sound
Posts: 10,952
Sounds like the little zone control damper motor has gone out. That's happened to mine.
If yours is like mine, you can open the damper until it's replaced by turning off the power, pushing in on the little red button in the damper motor box on the ductwork, and turning the exposed shaft of the damper a quarter turn with a pair of channel locks and then releasing the button to hold it open.
The damper won't close again until the button is pushed and/or the motor is replaced.
Good luck!
Old 10-31-04, 04:50 PM
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thanks for the input. But there are no ducts or dampers, it's a hot water baseboard system. So it must be something else.
Old 10-31-04, 05:59 PM
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Join Date: Dec 2002
Location: Easton, PA
Posts: 3,245
It could be the zone valve motor. If you have 24 volts at the motor and the valve isn't opening, blame the motor. You can replace just the motor if you can find one. Or you can replace the while head. Some are removable with 2 screws and the older ones did not come apart.


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