We bought a home last year with dual zone control. In my opinion, it's really not working very well. It seems like zone 2 needs heat more often than it should. It's a new addition and has excellent construction, window, doors and insulation.

My first questions is whether the return ducts should be controlled electronically by the system. Only the supply ducts are controlled at this time. So when heating or cooling a zone, return air is being drawn from both zones? That doesn't make sense to me.

My thought is when zone 2 is turned way down (when not in use), and I call for heat in zone 1, return air is being drawn from zone 2, even though no supply is going into zone 2? How is Zone 2 making up for the air Zone 1 is stealing?:confused:

Thanks for your assistance!

Kevin

First if you are not supplying zone 1 with air then zone 2 can not pull return air out of zone 1 except for just the part that leaks through the duct wystem.

Is this and upstairs and downstairs system?

First if you are not supplying zone 1 with air then zone 2 can not pull return air out of zone 1 except for just the part that leaks through the duct wystem.

Is this and upstairs and downstairs system?

One Zone is the entire split entry house. The other zone is the old two car garage converted over to a mother in law apartment.

Many things could effect your zone system. First is that it was not designed correctly and that happens all the time.

Second is the fact that as part of the poor design they did not allow enough return air on each system so they had to use both returns to make up the difference. You failed to post what kind of system you have and the indoor units model numbers and brands. Post that info for further conversation.

The Zone System is EWC Ultra Zone BMPlus 3000. There are two dampers one ND3 and one ND4 on the house zone, both on two supply ducts. Then one ND4 damper for the supply to the addition.

There are two brand new EWC dampers on eBay that would be the correct size if I needed to put dampers on the return ducts?

Thank you for all the help!

Thanks for the zone info BUT I need to know the type of heating equipment this stuff is hung on. Brand and model number of furnace/air handler. etc.

It's a PAYNE, Forced Air, model # PG8UAA 036065. Converted from Natural Gas to Propane.

I know where hvac100 is going, so get the information he requests.

EWC seems to make nice zoning panels and correct me, but you probably have little or no interaction between the zones..

More importantly, you may not have enoge air colume to get to the garage. This would be apparent with a static pressure/cfm measurement which should have bee done when the system was balanced. Pulling return air from somewhere else could change the presurization between the zones providing there is a way to suck conditioned air out of a space.

The amount of air going in has to equal the amount leaving and takingit from another space could suck conditioned air from that other space. Open return ducts actually help with the equalization of pressure.

Hopefully, you have a bypass damper. Maybe electronic, maybe not. That doesn't help the conditioned spaces. It basically keeps the motor from burning up.

In a first order world, make sure the return air grills are about equal to the intake grills for the spaces. Report back with those numbers too.

Pay attention to the amount of air pumped out of the grills supplying the two spaces. It might be because of the lack of a booster fan for that space.

hvac1000 has some tricks up his sleave but the air handler info is essential.

You may, for that matter, be able to keep the CFM delived by the blower relaitively constant (depends on blower design) by essentially varying the speed so that a percentage of Flull load amos are reached.

So, an improperly sized duct or balance is a tough problem to solve.

Simple terms:

1. You really need at least 400 FM of air per ton in order to cool properly at the air handler with everything open and running in full cool mode.

2. Yu eed under 1 W.C. (inches of water) pressure in arder not to put undo strain on the motor. The bypass damper regulates this.

3. The individual damper positions vary the CFM required for each room.

Too much air velocity, the ducts become noisy. To little, there's inadequate cooling.

Bad placement can result in static ar pockets, mixing and/or comfort problems.

Now back to square 1. Duct design.

Report back with the equipment models.

Save these to your computer for future need.

http://www.gogeisel.com/geiselonline/support/Payne/PG8D_Gas_Furnace.pdf

Your propane conversion kit info.

http://www.xpedio.carrier.com/idc/groups/public/documents/techlit/ag-ganp-31.pdf

Complete service guide.

http://www.docs.hvacpartners.com/idc/groups/public/documents/techlit/sg-pg8d-03.pdf

The above info has nothing to do with your zone problem but since I had this info I thought i would pass it along especially the service manual since when the unit breaks down you or a service person will now have the correct document with which to make repairs with.

From what you have said

It seems like zone 2 needs heat more often than it should

What is leading you to believe the above is true?


My first questions is whether or not the return ducts should be controlled electronically by the system.

The return air ducts do not have to be controlled by there own set of dampers. There are various reasons for this but usually it is just cheaper to not control the returns and many times even the supply dampers are set not to close tight so a dump zone is not necessary. (DUMP ZONE) depending upon your exact design which I have no idea exactly what it is besides just two zones a dump zone is needed to dispose of heated or cooled air that will not flow into the one zone area. The problem is that a furnace is sized to heat the entire area and when the entire area is not being called upon to be heated the furnace can generate to much heat and the same can be said for A/C on cooling so this heated or cooled air has to have a place to go or the equipment will have problems/damages from lack of air flow.

I believe the design of your system is setup to allow dumping through loose zone dampers to prevent that equipment damage and if return zone dampers were installed the damage possibility's to the equipment would be worse.

My thought is when zone 2 is turned way down (when not in use), and I call for heat in zone 1, return air is being drawn from zone 2, even though no supply is going into zone 2? How is Zone 2 making up for the air Zone 1 is stealingMy thought is when zone 2 is turned way down (when not in use), and I call for heat in zone 1, return air is being drawn from zone 2, even though no supply is going into zone 2? How is Zone 2 making up for the air Zone 1 is stealing

Your home is an open system so one zone does not have to make up air for its removal from another area. All the areas are connected since your zones are not perfectly sealed. Also air will move from the returned space back to that same space by pressure balance. Remember you're pulling air out but you are also pushing it back in to the same space from where it was just removed.

Your system is not perfect that is for sure but it was cheaper to do it this way. Remember builders use the cheapest contractors available who work at the cheapest price. This is a fact unless you hired the HVAC contractor and then you made the decision to hire the one that did the work.

Tip offs to marginal contractors.

First the equipment.

Payne is a cheaper level brand made by the Bryant/Carrier group.
Just about any contractor that is breathing can by Payne brand but not Bryant or Carrier brand since they require more training and dealer involvement.

Second the zone

You have the cheapest zoning available to go along with the equipment. Years ago we used to use a pressure sensitive device to lower the blower speeds when only one zone was calling for heat or A/C to help prevent part of your problem but items like this do not come cheap. Your system can be fixed to operate correctly but at what cost? The cost will only be known if you obtain estimates from two different company's and find out exactly what they intend to do to correct your situation.

I have no miracle cure and I am rather blunt when it comes to subjects such as these. I do no engineering on this site and I get enough of that at the university to start with. I do feel sorry for the many people who buy new homes expecting quality work when in most cases that does not happen. New home builders are the HVAC contractor's worst nightmares and almost all quality HVAC contractors will not do new construction because of this fact. So the builder is left scraping the bottom of the barrel when he needs a HVAC installer.

The HVAC system in the home is a hidden item and the builder knows that better kitchen cabinets and counter tops is what actually sell the home because it is visual in nature. Over the years I have been in new homes (Home-A–Rama's) when I overheard a prospective buyer say wow look at those cabinets, did you see that great bathroom, or this carpet sure is soft but supple but not once did I hear wow get a good look at that HVAC system I bet it really works well. Then the person buys the home and complains the first floor keeps the A/C temperature at a perfect 72 degrees but the up stair is 80. One saving part of this entire subject is that they can always look at those great kitchen cabinets or sleep on the soft carpet since it is to hot up stairs in the bedroom.

Good luck with your corrections if you decide to make them.

Thank you for your help. I was hoping I had an easy fix here. We had a dual zone system in a previous home that worked awesome, hense my fustration with this system. Most of the work in this home was done by the previous owner, and was shotty.

I'll give that contractor from our past a call and have him out to look at it.

Again, thank you, I appreciate your efforts!

Kevin