2 zone Motorized Damper works most of the time, but....

Old 09-24-12, 03:03 PM
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2 zone Motorized Damper works most of the time, but....

I have a two story home with 2 zones. The system will work 7/10 times, but the other times I'm forced to go up in the attic and pull it open manually. The ducts have a motor on top with a little bolt I can pull to force the motor to open it. I'm thinking the motor must have a gear that is dull and not forcing it to open the damper. I'm just guessing and know absolutely nothing about HVAC. Some help would be greatly appreciated.
Old 09-30-12, 02:00 PM
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An easy test would be to have that specific zone thermostat call for heat/cool (with the other zone off) and check the zone board indicator lights (if so equipped) to see if the controlling board has that damper "open". Some dampers also have indicator lights (green if open, red if closed). It is a common problem and really one that you can do yourself.

If you are electrically inclined you can test for voltage across the "C/Com/Common" and "PO/OPN" terminals at the control board and again at the zone damper itself. Some zone boards and dampers are wired differently and only require power to open or close (use of springs).

There is usually a set-screw that attaches the motor to the damper arm, loosening that and removing the couple screws holding the motor to the damper assembly and it should be an easy replacement. Ensure that you use an exact replacement and correctly align the damper arm when installing the new motor. The usually have a mark on the end of the arm indicating the internal position of the damper.

Again, there are many different types of dampers so the wiring or replacement may differ.

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