Automatic HVAC air duct zone damper actuator motor replacement.

This article series explains both manual and automatic heating and air conditioning ductwork zone dampers & airflow controls used to control airflow through heating or cooling ductwork.

We describe how to find sometimes hidden manual duct dampers, and which way to set the duct damper lever to increase or decrease airflow through various sections of the ductwork and the building.

Replace Ductwork Zone Damper Actuator

An automatic duct damper is usually controlled by a room thermostat, which opens or closes a metal baffle inside of a warm air (or cool air) heating (or cooling) duct in order to provide multiple heating zone control in a building.

This discussion with InspectApedia reader James provides troubleshooting motorized HVAC ductwork zone dampers, illustrates how these systems work, where they are found, what goes wrong, and how to fix it.

You'll see that the homeowner ultimately has to replace several motorized zone dampers, using new motors connecting to existing mechanical dampers in the ductwork to restore the HVAC system zones to proper operation.

We include photos of step by step replacement of a failed zone damper actuator motor.

No Air Coming Out of One Zone in a Forced Warm Air Heating System

Have a 2 zone system. Zone 1 is main story and zone 2 is 2and story.

System is blowing air in zone 2, but when zone 1 tries to cycle, no air comes from the vents.

Have changed the filters, changed batteries in thermostats, swapped thermostats.

When zone 1 comes on for a bit, I get a supply air limit led come on, on my zone board. I believe I have an auto damper stuck. How do I "force" my dampers to open and close to check each for function? - On 2020-03-24 by James -

Reply by (mod) - troubleshooting a zone damper that's not working

James

The fact that you get good air flow out of one of your heating zones tells us that the problem is not the air handler itself: not the blower fan or main air filter.

Common problems that explain loss of air flow in one of several forced air HVAC zones are disconnected or crimped ductwork or a stuck zone control damper. Our starting point for more-extensive diagnostics of that trouble are

at AIR FLOW IMPROVEMENT, HVAC

But let's try this first:

Locate the Zone damper for the non-performing HVAC duct or zone and then try disconnecting the motor from the damper arm entirely.

That should let you manually turn the damper to open it.

If you find the damper closed and if you can manually get it open then we suspect the problem is in the zone damper actuator, and also you'll have made a temporary emergency repair to get heat to the cold zone.

Steps to avoid damaging the zone damper motor & to safely make a temporary bypass to open or close a duct zone

Ok, thanks. I wasn't sure if that would damage the the motor or not. I'll give that a shot, thanks for the feedback. - On 2020-03-24 by James -

Troubleshooting a zone damper that's not working

James

1. be sure power is off to the device so you don't get zapped

2. simply try not to bend anything during disassembly; most likely you'll find that the wiring connections can be simply un-plugged

- you're unlikely to damage the motor by removing it.

Let me know how this works for you. - On 2020-03-24 - by (mod) -

The zone damper baffle itself is not stuck but the motor doesn't work

Well, the damper is opening and closing with no issue.

With the power attached, there is no resistance on zone 1, but on zone 2 it has resistance.

I now have zone 1 open, but believe the damper actuator or motor to be no good. I have the Honeywell M847D1004, but know they don't make that one anymore.

Should I try to find a replacement motor, or just replace the whole thing with the M847D-Zone (the newer model of the one that is on my unit)? - On 2020-03-29 by James -

Here are Some Replacement Motors for Zone Damper Actuators

James

Thanks for the photo and added M847D1004 zone damper diagnostic detail. The zone damper actuator motor is pretty simple; if we could find a replacement and if it were my building, I'd figure that as I was facing having to replace the whole zone damper unit anyway - with the M847D that you cite - that there's not much lost if I try repairing the old unit first as long as the cost is low.

A replacement zone damper actuator motor for the Honeywell M847D1004 is sold by hvacsurplus.com and is shown below. The cost is under $50. U.S. (a bit more than half of an entirely new zone damper actuator as I'll cite below).

The vendor says "Replacement for Honeywell M847D1004, M847D1012, and all Honeywell M847D Series Motors for ARD dampers."

"Drop-in replacement motor actuator for Honeywell M847D1004, M847D1012, and all Honeywell M847D Series Motors for ARD dampers, RZ3-1M 680474058020. Zonefirst models ZDS, ZDB, and RTS. For normally open, as used with Honeywell and Trol-a-Temp zone control systems."

- as they say it will work for your zone damper (if I understand the product literature correctly), that's a reasonable option. On 2020-03-29 - by (mod) -

A complete new Honeywell M847D Zone Damper assembly costs about $90. U.S. and is very easy to install - just 2 wires to connect and less than 10 minutes work as long as the installation location is easy to access.

And below is a different Honeywell M847D1004 Damper Actuator replacement photo from Amazon's sale page for the product. This one probably is a match for your zone damper actuator motor.

So if you're inclined to fool with the existing zone damper by replacing just the actuator (motor) it looks as if you might find one - have I missed something?

Replace the entire zone damper assembly or just the actuator motor?

No, you didn't miss anything. I really appreciate the help, and the time you took to do it.

I saw all of the posting except the last one you put up. Just trying to mull over my options to find my best one. Both actuators are easy to access, so any work will be relatively simple.

What would you do, would you just replace the whole thing, or try to "rebuild" (the last option you posted)? I'm not married to any particular brand name either if you have another option to suggest. - On 2020-03-29 by James

I don't mind spending a little more on a better/ more reliable option, I just don't do this for a living, so I'm learning on the go.

Choose a replacement zone actuator that looks as if it easily fits the existing zone damper control

That last zone actuator motor looks as if it fits your damper control.

If you're comfortable disassembling and wiring the two connections, replacing just the actuator motor lets you leave the actual damper mechanism in place with least disturbance - I'd give it a shot.

Let me know how it goes - perhaps post a photo of your steps. - On 2020-03-29 - by (mod) -

Photos of step by step replacement of a ductwork zone damper

Got it fixed. Thank you so much for the help. - On 2020-04-08 by James -

Have some pics of my steps along the way.

To get the final line up correct (no pictures, needed both hands),

I removed the duct from the damper and manually moved it to fully open and fully closed.

. .

I watched the indicator on top to ensure it was correct, then tightened down the bolt on the shaft, reconnected the wires, and put the duct back on

It works like new now. Thanks again for the help!

 

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Reader Q&A - also see RECOMMENDED ARTICLES & FAQs

How do I find the zone dampers on my ductwork

How do I find dampers in my ductwork that were put in before I purchased the house? - On 2017-01-10 by New Buyer -

Reply by (mod)

Normally the zone dampers in ductwork, IF any were installed, will be in an accessible location, so simply follow your HVAC ducts, starting at the air handler, and look for controls mounted on the ductwork such as those shown above on this page.

Keep in mind that many homes have heating and cooling ducts that either use no automatic duct dampers or zone dampers OR there may be manual dampers - simply a lever that allows the installer or homeowner to increase or decrease the air flow in individual zones.

 

Motorized HVAC zone control damper is not opening or closing

my house has "zone" control with dampeners to close off the upstairs over the gargage room unless that thermostate is on - the room is not cooling.

I have located the damper under the house. What are some causes for the damper not opening and how to repair them? condensation, motor to damper? silcon glued properly? - On 2011-05-28 by Becky

Reply by (mod) -

If a motorized HVAC zone control damper is not opening or closing, most likely the motor has failed, or the thermostat that operates that zone control is off or set in an incorrect position.

See

• ZONE DAMPER CONTROLS
• ZONE DAMPER ACTUATOR MOTOR REPLACEMENT

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Continue reading at ZONE DAMPER IO MANUALS & WIRING GUIDES or select a topic from the closely-related articles below, or see the complete ARTICLE INDEX.

Or see these

Recommended Articles

• AIR CONDITIONING & HEAT PUMP SYSTEMS - home
• DAMPERS & DRAFT REGULATOR TYPES
• DUCT SYSTEM DESIGN SIZE & DEFECTS - home
• FIRE & SMOKE DAMPERS, AUTOMATIC
• FURNACES, HEATING - home
• MANUALS & PARTS GUIDES - HVAC - home
• ZONE DAMPER CONTROLS - home
• ZONE DAMPER ACTUATOR MOTOR REPLACEMENT

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ZONE DAMPER ACTUATOR MOTOR REPLACEMENT at InspectApedia.com - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice.

Or see this

INDEX to RELATED ARTICLES: ARTICLE INDEX to HVAC DUCT SYSTEMS

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