HVAC Zoning install

jlegault

Active Member
I am about to embark on setting up a zoned system for my upstairs HVAC system. It's been hard to find resources that can help a DIYer. There are a few things I need help with and was hoping someone on this board may have the experience...

My ducting is flexible insulated duct work, and I can't figure out what the interior diameter of each hose is. The exterior diameter seems to be 12" and 9" for the hoses I will need to install dampers in. Anyone have experience doing this? I would like to order the dampers without having to rip stuff up to check the interior diameters.

Second question is the barometric bypass - Is it all I really need to protect my compressor? The upstairs will have 4 zones and is 1500 Sq feet. I am not sure of the size of the A/C unit.

Thanks in advance.

Jacy
 

wengelab

New Member
jlegault said:
I am about to embark on setting up a zoned system for my upstairs HVAC system. It's been hard to find resources that can help a DIYer. There are a few things I need help with and was hoping someone on this board may have the experience...

My ducting is flexible insulated duct work, and I can't figure out what the interior diameter of each hose is. The exterior diameter seems to be 12" and 9" for the hoses I will need to install dampers in. Anyone have experience doing this? I would like to order the dampers without having to rip stuff up to check the interior diameters.

Second question is the barometric bypass - Is it all I really need to protect my compressor? The upstairs will have 4 zones and is 1500 Sq feet. I am not sure of the size of the A/C unit.

Thanks in advance.

Jacy
I installed a 4 zone system for my upstairs HVAC last year, using motorized dampers from Retrozone.com. They fit fine on my flexible insulated ducts, using 6", 8" and 12" diameter dampers.

I did not use a barometic bypass. Instead, I left a duct uncontrolled that serves a large open two story area, so that area is always receiving air when any of the zones are working. There must be some loss of efficiency, but I avoided any angst over possible damage to the compressor. However, when only one zone is open I do hear a bit of an air rush out of the always open zone.

Good Luck
 

dublin00

Member
wengelab said:
jlegault said:
I am about to embark on setting up a zoned system for my upstairs HVAC system. It's been hard to find resources that can help a DIYer. There are a few things I need help with and was hoping someone on this board may have the experience...

My ducting is flexible insulated duct work, and I can't figure out what the interior diameter of each hose is. The exterior diameter seems to be 12" and 9" for the hoses I will need to install dampers in. Anyone have experience doing this? I would like to order the dampers without having to rip stuff up to check the interior diameters.

Second question is the barometric bypass - Is it all I really need to protect my compressor? The upstairs will have 4 zones and is 1500 Sq feet. I am not sure of the size of the A/C unit.

Thanks in advance.

Jacy
I installed a 4 zone system for my upstairs HVAC last year, using motorized dampers from Retrozone.com. They fit fine on my flexible insulated ducts, using 6", 8" and 12" diameter dampers.

I did not use a barometic bypass. Instead, I left a duct uncontrolled that serves a large open two story area, so that area is always receiving air when any of the zones are working. There must be some loss of efficiency, but I avoided any angst over possible damage to the compressor. However, when only one zone is open I do hear a bit of an air rush out of the always open zone.

Good Luck
What did you use as a zone controller?
 

kwilcox

Active Member
I used Desco Design myself to calculate CFM loss when I reconfigured my ductwork. Its a great resource. I'm running a rather unconventional two zone system in my ranch style home that uses inline duct fans to change the plenum pressure differential between the sleeping and living areas.

The point is this: don't be afraid to think outside the box as you contemplate your upgrade!
 

DavidL

Senior Member
Found a tidbit of an "EZ Trap" condensate switch on the Desco site. This would have come in handy for my system if I knew it existed. Switches off the A/C if the drain is clogged. $27.33 via eBay.
 
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