Issue with damper

Hello to all and thanks for any help you can provide to me.

I have central (forced) air divided up into three zones in my home.

Zone 1 and zone 2 work fine and call for cool air (activate the compressor outside) when I lower the thermostat for that zone..

Zone 3 only turns on the blower. It does not activate the compressor. Also, the damper for zone three seems to be stuck open all the time. I will get cool air if Zone 1 or 2 call for cooling.

I have the common three zone panel made by Honeywell probably from the 1990's.

Are these two issues related or do I have two separate problems?

Thanks!

 

Welcome to the forums.

Yes... the two problems are related. Looks like a board issue.

 

OK.

I did purchase a new Honeywell three zone panel a month ago as a back up for this oldy.

Guess it's time to upgrade if you feel this will solve both issues.

 

There isn't an external problem that can cause that.
The stat should demand the damper open. blower run and condenser run.

Did you try to reverse the open and close lines to the damper to see if might be a mechanically stuck damper ?

 

I'm a bit confused. Your initial reply stated it might be a board issue. Meaning the large control board correct?

I did try swapping one thermostat from one zone with this #3 zone. No change. All I get is air with no compressor running.

There are two leads that go to the damper for each zone. My thinking was these are 24v AC to the damper motor. Would reversing these AC leads cause the motor to run in the other direction?

Please advise.

 

Sorry... I should have asked you to post the model of the zoning board.
I'm dealing with several threads at different locations with zoning boards.

A two wire damper is usually power to open and no power with spring close.

 

When none of the zones are calling for cooling the damper output is 24vac all around and all three green LED's are lit. The yellow System LED of off.

When a zone calls for cooling, that zone damper goes to 0vac only, the green LED for that zone is lit and the others are off. The yellow System LED is also lit.

However, if zone 3 calls for cooling by itself, the yellow System LED stays off and I get no compressor.
The damper does go to 0vac (as it should ?) and Zone 3 green LED is on by itself.

So, my question is:
If the damper for zone 3 is jammed in the open or partially open state, will that prevent the compressor from coming on for that zone?

Thanks!

 

No... the damper won't cause the condenser not to activate.
That indicates a board problem.

About 3 minutes after the call ends (purge) the damper stays open and the others stay closed.
When the purge ends all dampers open.

 

Located the three dampers in the ceiling. There is a large Allen head bolt that secures the entire box to the damper shaft. Loosening that and off it came in my hand,

I took it to my bench to have a better look.



Applying 25 volts AC the motor, it would rotate the mechanism to about 25% of the travel then bog down and stop. Even nudging it would not get it to restart.

They're cheap to buy on Amazon for around $28, so I have one on order.

Still need to trace out why the compressor does not run for zone 3 but I have a feeling it is the relay for that zone.

Stay tune.