zoned systems have multiple tstats
not multiple units.

do you mean another type of system?

Not enough information. Are the HVAC units electric heat pumps or air handlers served by a boiler too?

Renovator, it is a natural gas heater. I don't think there is an electric heat pump or boiler.

When I went in the basement the other day, there were 2 seperate units, which made me wonder what they were. Our current hvac is just one outdoor ac unit, and the one furnace unit in the basement.

I am thinking the builder made a mistake (the 2 zone is an upgrade, $7100.00) and I want to keep their mistake if in fact it is a 2 zone. I just wanted to confirm before I talked to them. That is a big chunk of money, and I don't want to pay full price. Maybe I can talk them down since all the duct work is in place.

I know it has 2 seperate outdoor AC units, but what about the indoor component?
When I went in the basement the other day, there were 2 seperate units, which made me wonder what they were. Our current hvac is just one outdoor ac unit, and the one furnace unit in the basement.

so you have two condensing units outside
and two furnaces in the basement.
two complete systems. with ductwork in place..
this is going to be difficult to not pay full
price on. to retrofit it to one system
may entail resizing units & re-working ductwork.
it may not be do-able.
can you post model numbers of outdoor
condensers & indoor furnaces?
how big is the house?
how many floors?
did you not have a conversation with hvac
company to understand what was being installed?
or builder?
more infor please.

best of luck.

DD2 purchased a home from an HVAC representative. It was built in the 90s, and has 3 zones. 1 unit outside, 1 furnace in the garage (no basement). 1 main control that works all three zones, plus 2 temperature controls (but you don't mess with their buttons).

To be honest, the north side of the house (guest room now playroom, and child's bedroom) stay cooler than she'd like sometimes... no matter what she does, since the temperature control is located in the hallway between the rooms (along with the return for that area) and it gets heat from the LR/DR zone. So when the baby's room is closed, it can become too cold sometimes.

ERLA, do you know how she can fix this? btw, there is one large filter in the attic (DH hates to get it out to clean). He is thinking about removing it and just putting in return filters.

(Haven't seen you in awhile ERLA. I hope things are going well for you.)

I'm also confused by the question.

We have 3 zones- that means 3 furnaces and 3 AC units outside. 2 are in the basement and one is on the second floor.

Allison, we have a slightly different issue. There is a zone that supplies the master bedroom suite, guest bedroom suite and laundry room. The thermostat is in the master bedroom. The radiant heating from the master bath keep the master suite pretty warm so the unit rarely kicks on. This means the guest suite is quite cold. Most of the time it's not an issue, but when we have guests we have to manually override our program or turn down the radiant heating.

This post was edited by pps7 on Thu, Jan 10, 13 at 16:35

Hey Allison.
its hard to trouble shoot these temp
differences on line...but I'll give it
a shot.

having the baby's bedroom on the same
zone as the living/dinning room
may be the issue.
the setting may be to reduce amount of heat
after a certain time of night to living/dinning
area.

the usual zone setup (and this is a true zoned
system btw..not multiple systems) is motorized
dampers a control panel usually located by
furnace and tstats for the individual zones.

I'd check the settings on the tstat for that
zone.
also..the babys room, with the door closed
may not be letting the air return.
which also could effect the temp difference.

the thing about motorized dampers is that the motors
can go out, and not respond to call for air.
this should show up as an error on the tstat..but
may be an older zone system. hard to say.

another thing to check would be to see if
any of the ducts to this area have become
disconnected. or if they are restricted,
or have excessive duct leakage.
you could send dh into the attic.
(sorry Allison's DH) when the unit is
running feel around the plenum where the
ducts take off for leakage.
not as good as a duct test, but it will
give you some idea of leakage.

what brand is the zone system?
is original home owner/hvac rep still with
the original installer? having them, or someone
experienced with the brand of zone control would
be a good thing.

does the house have returns in each zone that
hook into a central return with one filter
in the attic @ the furnace?
if so, then sealing off the filter rack at the
furnace..the door that opens to remove the filter..
would be necessary so that this area wouldn't
suck in attic air. then putting filters
in each return would work.

just remember not to use the 1" pleated
filters. they are too restrictive.
here is a picture of a 4" media filter that
fits into existing return.

Things are good here. Hope all is well with
your & your expanding family!

pps7
you have 3 units controlling 3 areas.
while companies like to call this zoning
because it breaks down the house into
different areas to be heated/cooled indivudally
it is multiple systems, not a true zoned system.

a true zoned system is one unit & multiple tstats.
in the area where the furnace is located
will be a main control board that tells the
motorized dampers installed on the ducts
when to open, how much to open & when to close.
this main control board communicates with the
individual tstats to each zone.

this adds 1-2K to price of one system.
hvac company has to go to school to lean to
install these systems.
companies that do multiple units usually
are oversizing the units just as they would
do in an older existing house. like they have
done for 25 years.

best of luck.

When we bought our current house, it had 2 separate systems, as it sounds like you are getting -- 2 furnaces in the basement and 2 a/c units outside. In our case, one unit serves the 1st floor and the other serves the 2nd. The upside of this is that even if one system breaks, you still have heat and a/c on the other floor. This saved our butts a few times, as our furnaces were some kind of weird brand and when things broke, parts had to be special-ordered from Canada and took weeks to come. During that time, we would have been FREEZING had we only had the one unit but with the 2, at least we could go to the other floor (and when the 2nd floor was broken, the heat would rise from the 1st so the 2nd floor was tolerable).

The downside of this was having to maintain 2 separate systems. It meant paying for 2 A/C cleanings each spring, 2 furnace tune-ups each winter, 2 service contracts if we so opted, twice as many filters to replace, and of course, twice the opportunity for stuff to break -- it seemed like at least once a year, something would break on one of them -- but financially it was never enough of a repair cost to make up for having to carry service contracts on both furnaces, so we just paid out of pocket.

We lived with the setup for several years but finally one of the furnaces died beyond repair. We were really sick of paying twice the maintenance, so we did a lot of research into whether it would be better to replace with a "zoned" system with one unit and the motorized dampers, but ultimately, we went with 2 separate systems again. We talked to a few HVAC guys (two of which were out-of-the-area friends of my parents and so not trying to sell me anything). They all said that you don't get the same level of control with the motorized dampers that you do with the 2 separate systems especially since our ducts weren't initially designed for it -- they said after living with the two systems, moving down to a single zoned unit would mean that the upstairs would be too hot in the summer and downstairs too cold in the winter. Plus the whole system of motorized ducts is apparently kind of fussy and offers its own opportunity for things to break.

Anyhow, as someone said above, the motorized damper system should only be a 1-2K upgrade on the cost of the single unit, so having paid a $7200 upgrade fee, I would think the builder intended to give you 2 separate systems all along. (Besides, with the motorized damper system, you'd only have 1 outdoor unit, not two.) So get ready to shell out twice the maintenance for everything...but take comfort in the fact that your upstairs and downstairs (or whatever your 2 different zones are) will always be exactly the temperature you want!

I did not pay to upgrade it. The house is not supposed to have it. They just went ahead and put it in. It is a mistake. I am not willing to pay for their mistake, nor do I want to have it all ripped out.

I just wanted pictures to verify it was a mistake.

There are no outdoor units as of yet.

When the OP described the system as a "2 zone hvac unit" it is understandable that no one would think the system was two separate HVAC systems for two different parts of the house but apparently it is. If the OP did not know how to describe the system a photo should have been posted instead of asking others to post photos of their system. Problem solving starts with an accurate definition of the problem.

The upside of this is that even if one system breaks, you still have heat and a/c on the other floor.

I hear that a lot. its a classic tatic
for selling multiple units because they can't do
a zoned system correctly.

also it gives them the chance to sell more
tons. biggest size is 5 ton, this way you
can have more..cuz they tell you bigger
is better.

these companies don't have a clue
about load calcs & better installs.

In response to your request for more information, I stated that there were 2 seperate furnace units in the basement.

Honestly I did not know that a proper 2 zone unit was one furnace, with special ductwork. The builder had always advertised the upgrade as "2 zone" so I was wondering if 2 seperate indoor units is 2 zone.I wanted pictures from other "2 zone" units, so I could compare them. I googled, and did not find any.

I thought that certainly some one on here had that type of system, and would share.

Was that not enough information? Yes I have pictures. No, I do not those pictures floating around on the internet. Just like I do not post pictures of my children, I do not post where I live, or future homes.

The posters on the kitchen side are much nicer,and not as snarky as on this board. People should not feel stupid asking questions, this board is supposedly for help, and for people building houses.

If you don't want to offer help, then don't chime in.

amazing.

You wanted other people to share pictures, but you wouldn't consider sharing any with others?

ERLA,

having the baby's bedroom on the same
zone as the living/dinning room
may be the issue.
the setting may be to reduce amount of heat
after a certain time of night to living/dinning
area.

The baby's room isn't on the same zone as LR/DR. It's baby's room, play/guest room, bath. The return and tstat you don't touch is in the hallway... but the LR/DR is RIGHT there, so I think the one that reports the bedroom temp is reading the LR temp sometimes - making his bedroom cold.

It's a Trane system. The previous owners left all the booklets, etc. I will check to see if company is still in business that did the install. I'm not sure the company we used has much experience with them, but I could be wrong.

Yes, I think DH needs to get into the attic - his least favorite thing to do, but at least it's not summertime.

does the house have returns in each zone that
hook into a central return with one filter
in the attic @ the furnace?
if so, then sealing off the filter rack at the
furnace..the door that opens to remove the filter..
would be necessary so that this area wouldn't
suck in attic air. then putting filters
in each return would work.

just remember not to use the 1" pleated
filters. they are too restrictive.
here is a picture of a 4" media filter that
fits into existing return.

Yes, the filter is at the furnace. I read DH your post. He said thank you. He will get in attic this week/weekend and make sure things are working correctly. And I will check on company.

Have 2 gbabies now. DS and K had a girl in early June. :)

Was that not enough information? Yes I have pictures. No, I do not those pictures floating around on the internet. Just like I do not post pictures of my children, I do not post where I live, or future homes.

One would think you could take a picture of your furnace or outside HVAC system to post without including your children or address in the picture. :-/

But I bet her cat/dog would make it into the picture ... those sneaky critters always get into the shots!! ;-)

First house - one HVAC system with 9 zones. Had a "computer" system that managed the dampers for the different zones. Previous owners had installed it. It was a system that didn't make it in the mass market and only one local guy knew how to service/program the system. Good idea and it mostly worked as advertised!

Second house - 3 zones with a HVAC system for each zone. First floor, second floor and 700 sq.ft bonus over garage.

Third house - 3 zones with a HVAC system for each zone, first floor and second floor. Third zone is a guest house with its own HVAC.

Posted by Laura12 (My Page) on
Fri, Jan 11, 13 at 17:34

You wanted other people to share pictures, but you wouldn't consider sharing any with others?

*

Thank God.

I thought I was the only one that noted that!

You claim your system description was:
"2 seperate furnace units in the basement"

Your actual description was:
"2 zone hvac unit that is in the basement"

In response to a request for more information you said:
"it is a natural gas heater. I don't think there is an electric heat pump or boiler."

Then you said: "When I went in the basement the other day, there were 2 seperate units"

You never said these units were furnaces so you should have a bit more sympathy for those you made run around in circles trying to help you. If you don't know much about HVAC systems posting a photo of your system would have been a simple and appropriate courtesy.

The members here are generous with their time and knowledge and it is easy to take that service for granted. I think you owe everyone an apology.

This post was edited by Renovator8 on Tue, Jan 15, 13 at 8:29