# Adding Zones to HVAC Zoned System



## Movingshrub (Jun 12, 2017)

I have a Carrier infinity system with variable speed air handler and multi-stage compressor.

The system was designed with two zones. I really needed three or four. One zone covers both the top and bottom level of my house, as a result, the bottom level is always cold.

I'm considering adding dampers to each ducting run serving both the upstairs and downstairs, and turning that one zone into two. Any issues or considerations I'm overlooking? On a potentially related noted, the return is on the middle level of the house. I have access to add another return to the lowest level, but don't have any viable way to add a return on the top level.

Would adding a return on the bottom assist by pulling the coldest air back into circulation? Is this a situation that requires a joint solution or would either the additional return, or the additional zone, solve my issue?


----------



## jayhawk (Apr 18, 2017)

Perhaps a manual T is in order, minimally?

Manual J: Load Calculation
Manual S: Equipment Selection
Manual D: Duct Design
Manual T: Air Distribution

I don't know enough about zoning but static pressure matters on equipment life. A neighbor kept same distribution / supply plumbing but added 1 or 1.5 in tonage. wasn't 'builder grade' equipment...tits up 3 yrs later

Dampers leak (externally) a little bit, they have to. Can you dampen somewhat at the grill?

Upstairs suboptimal in summer then too?


----------



## turfnsurf (Apr 29, 2020)

Movingshrub said:


> I have a Carrier infinity system with variable speed air handler and multi-stage compressor.
> 
> The system was designed with two zones. I really needed three or four. One zone covers both the top and bottom level of my house, as a result, the bottom level is always cold.


I don't have any suggestions, but I did have a question.

How did you determine how many zones that the system _should have_ been built for?


----------



## Movingshrub (Jun 12, 2017)

turfnsurf said:


> Movingshrub said:
> 
> 
> > I have a Carrier infinity system with variable speed air handler and multi-stage compressor.
> ...


Ah. Entirely a guess.

The installers went with a zone for the north and south end of the house because that's how the ducting was laid out. There was an acknowledgment that it wouldn't be ideal. I wasn't sure how good or bad that would be. My assumption is one zone for each particularly unique climate/requirement.


----------



## quadmasta (Apr 3, 2019)

You're going to run into bigtime static pressure issues unless you establish a dump zone which kinda defeats the point of the zoning.

Do you run your system fan or set it to auto? Try changing your comfort profiles to run the fan at least on low all the time and see if that changes anything.


----------



## GreenHorn (Nov 23, 2018)

The system was designed with two zones.

You state that you have 2 zones. If this was the case you would have 2 thermostats (control) each controlling their own zone. It sounds like you really only have 1 large zone with temperature requirements that are different. 
A Carrier Infinity System is a very good system (certainly not builder grade). Because the system is variable speed, it modulates based on demand(which is a GOOD thing). The concern is that the zoning system Carrier uses is proprietary damper/controls and can be very complex if the average person is not familiar with it. Carrier technitions typically attend specific training classes to install and service the system properly.


----------

