Zone damper system

danstar25 · 12-23-2008, 11:56 PM

I have the following problem:
This is the first winter i have spent in this home. With the t-stats programmed correctly i have been getting heat coming out the vents in zone 2 when there should not be. I went in the attic and observed the motor arm for that damper was opening and closing when it should. I thought the damper may have been stuck open so i pulled the ducting off the box and the damper itself is shorter by about 2 inches. So when it closes the air is still getting around the closed damper.

Is this like this for a reason or was the wrong size installed?

integlikewhoa · 12-24-2008, 12:01 AM

Was there any foam around the inside of the duct where the door is? Useally the damper has foam stop point that it seals against around 1" all the way around the inside. So when the doors closed it seals up against this. Maybe that came loose and went for a ride down the ducts somewhere. Without that it would leave a gap.

integlikewhoa · 12-24-2008, 12:06 AM

It also might help if you tell us was dampner this is. Im asuming this is like a Honeywell ARD# what ever the size of duct is. If its a retro style of add in dampner after the duct was in then I dont know.

**beenthere** · 12-24-2008, 12:54 AM

Does your zone system have a bypass damper.
If not, they may have used a 2" shorter damper to prevent over heating the heat exchanger.

danstar25 · 12-24-2008, 01:20 AM

I think its a ZD damper. The yellow lines show the space the air is allowed to go thru when the dampersw shut.
Im not sure if i have a bypass damper? What do i look for and where?

integlikewhoa · 12-24-2008, 01:22 AM

Quote:

Originally Posted by beenthere

Does your zone system have a bypass damper.
If not, they may have used a 2" shorter damper to prevent over heating the heat exchanger.

I guess anythings possible, but wouldnt that defete the purpose having zones, when they never really close?

integlikewhoa · 12-24-2008, 01:27 AM

A bypass damper bypasses air from the plenum comming out of your unit going back into the return air system or dumped off in an uncontroled area. Its usally a manual damper with a weight on for adjustment, that when the majority of the zones start closeing off the pressure builds up in the ducts so it releves the pressure.

Think of it this way. Your blower it pushing enough air to feed the whole house, then you change the zone so only one room or one zone (smaller then the whole house) is calling for air, all the dampners close except one zone which is alot smaller the air in the system builds up and slowes down so a bypass damper (with a wieght on it) starts to open to release the air either back into the return air plentum or return air line going to the plentum or something along those lines (can be dumped in a hallway or closet too), that way the air just makes a loop and passes back threw the unit again.

integlikewhoa · 12-24-2008, 01:33 AM

Quote:

Originally Posted by danstar25

I think its a ZD damper.

Naw I think its a mickey mouse job. I also think that "beenthere" is probley right, looking at that picture, theres no way that it will close all the way. Looks like it made to do what its doing now. Uless they had something shoved in that corner blocking the air flow, which doesnt look likley.

**beenthere** · 12-24-2008, 01:43 AM

It can defeat the purpose.
But its done every so often.

integlikewhoa · 12-24-2008, 02:03 AM

Quote:

Originally Posted by beenthere

It can defeat the purpose.
But its done every so often.

I cant belive it but I'm sure its true. And to think I wasted my time filling the complete duct with the dampner and added a Bypass. LOL

**beenthere** · 12-24-2008, 02:27 AM

Some contractors try to save some money by not having to pay for the bypass damper and time to install it, plus the duct for the bypass.

They under bid other companies, and then try to save money on the install.