[rickn]

Help with radiant and hydro-air setup

I will try to explain the best I can. I am building a 2 story house with a combination of hydro-air and radiant. My question is in regards to the 1 st floor only. My 1 st floor is 2200sq/ft. I am installing radiant flooring in my master bedroom and the kitchen/h.b./laundry room. There will be 2 zones for the radiant. I am having a 3.5 ton variable speed air handler and a 14 seer 3.5 ton a/c unit installed-all trane for the 1st floor. Duct will be run to all rooms for the purpose of a/c. Can it be setup so when heat is called for by the hydro system the ducts to my master bdroom and kitchen/h.b./laundry rooms close completely? Also will the system know that lees cfm is required because these other ducts have closed? I don't want the rooms with radiant to get heat from both systems.
Thanks

 

[swat]

Anything with controls is possible. Even reducing the air flow to the rooms would be possible to a point if you wanted but it may not be something you really want to do. The furnace / ahu would need to be varrible speed and if gas I would certainly recommend 2 stage. If heat pump then I would skip the 14 seer and go with something that actually has 2 speeds. Doing this will add quite a bit of cost to a job though. I would not recommend it simply because of the additional cost and try to explain why r why not. If cost is not a concern then go for it but get some one who is good with control wiring to help you. It is one of my favorite things to do so I always tinker with them.

 

[dash]

The main duct(trunk) to the areas that you don't want heat pump air to go to ,needs to be a separate duct form the rest of the home so a damper ,manual or electric can close it off.Their will likely be some leakage,very minimal.

Know in the heat pump mode you have more air then needed for all the other rooms,so a two speed heat pump might be helpful,but it will likely go to high speed at some point(unless low speed could handle the load).This means the ducts/grilles have to be sized to handle "all" the air .

If this is done,then the ducts for the radiant part of the home have to be equally oversized,so they get air flow in the cooling mode.

I'd have to run the numbers on the ducts ,to see if I think this would work properly or not.Above is just thinking about it.

Have you thought about a separte system ,for the rooms with radiant heat

 

[rickn]

If it would help here is a link to 1st floor
http://photobucket.com/albums/y288/hb01030/?action=view&current=1st.jpg

dash-why would the ducts to those rooms need to be oversized for cooling? possibly cause of extra drag from the ducts? Also when you say seperate system I take it you are talking about another air-handler for the cooling?

 

[dash]

Yes one system for the rooms with radiant,cooling only.


If you restrict X tons/btus of air from the rooms with radiant during heat pump operation,the other ducts need to be oversized to handle the air,if you don't oversize the ducts to the rooms with radiant,and the others are ,they will get little air flow in the cooling mode.

 

[jamierenae]

hi DASH! just saw you wrote in another post the following:
"Fridgidaire,low air flow from air handlers,if it is an air handler,the compressor was murdered!"

we just got a new Fridgidaire Air Handler 5 ton with variable speed and just did a posting on problems....
so this is a bad one?

YOU are near me... maybe I will contact you I think my AC Company screwed me over. can you read my other post.... and maybe you could give me some good advice and i can call you for a quote if my outside unit indeed is bad or just to find out if i was adviced wrong. I am in Palm Harbor, Fl. and it looks like i am in need maybe of a new AC company ? (sorry my engl. not so good yet, am german)
Thanks,
Manuela

 

[rickn]

Would this work?

Look at this sketch-link below
http://photobucket.com/albums/y288/hb01030/?action=view&current=1stfloorzoningrev1.jpg

Zone 1 and 3 will have radiant heat. Zone 2 will be heated by hydro-air. For hydro-heat couldn't I just set zones 1 and 3 thermostats at 50* and therefore the zone dampers would shut not allowing heat to those zones? All 3 zones would run off a 3.5 ton v.s. trane airhandler with heating coil installed for zone 2. All 3 zones would be cooled by the same air-handler. Do you think this is a good idea? Thanks again

 

[swat]

What are your ceiling hieghts and where is the equipment to be located as well as your grilles?

I would consider it a possibility.

 

[rickn]

1st floor 9ft. Airhandler will be located in basement near the stairs-close to center of house. Grills I am unsure of. Is this a good way to do this?

 

[dash]

Re: Would this work?

Look at this sketch-link below
http://photobucket.com/albums/y288/hb01030/?action=view&current=1stfloorzoningrev1.jpg

Zone 1 and 3 will have radiant heat. Zone 2 will be heated by hydro-air. For hydro-heat couldn't I just set zones 1 and 3 thermostats at 50* and therefore the zone dampers would shut not allowing heat to those zones? All 3 zones would run off a 3.5 ton v.s. trane airhandler with heating coil installed for zone 2. All 3 zones would be cooled by the same air-handler. Do you think this is a good idea? Thanks again

Sorry I'm in a heat pump market and made the wrong assumption.

The air handler will still have some minimum fan speed,post the model and someone can tell us what it is.

With the hyro coil,you may be able to tell it that you "X" kw heat to get the cfms required for that zone.

The zoning system,depending on what you use,may have an occassion to open the 50° zones.,so select carefully.


Sounds like your getting close to a solution,keep asking queastions,I'm not a Trane guy,so wait till you hear from the choochoo.

 

[hcpwr]

That looks like a good way to zone the system. I would use an EWC or Honeywell zoning system with a discharge air sensor and a motorized bypass damper that works off of sytem air pressure. You could also get a two stage Trane condensing unit with the variable speed air handler and let the panel control the stages depending on how many zones are calling.

 

[rickn]

any others?