[Miller257]

Well i bought a house, tore out the old oil burner and all the ductwork. made up some new ductwork and i'm ready to install it all tomorrow. i'm putting in zone dampers, because, well, i want a zoned system. I have an american standard variable speed furnace, 2 ton cooling. so were looking at about 800 cfm. I've split the house up into the following;

1. office
2. larger bedroom
3. bathroom, kitchen and small bedroom
4. living/dining room.

now my questions. do i need a bypass with a variable speed furnace. the furnace and zone board (Honeywell hz432) both have a terminal to slow down the blower when only 1 zone is calling. if i need a bypass, should i put in a barometric relief type with an arm and a weight, or a motorized with a static pressure control.

typically in commercial (which i mostly work in) you don't see a lot of bypasses with variable speed or freq drives.

 

[flashheatingand]

of the two options, i would go with the by-passwith the weighted arm. In setting the weight, turn all zones on and set the weight so it stays closed. This way, when two zones are opened, the by-pass will only open when necessary.

As an alternative to the by pass, you can have area #3 as a dump zone.

 

[jeremy-lvhm]

As an alternative to the by pass, you can have area #3 as a dump zone.

That doesn't even begin to make sense. Why dump BTUs where you don't want them? If they bypass they get used where you want them. If you dump them?????:no:

 

[flashheatingand]

The air still goes where you want. I have never heard of somebody complain that a kitchen or bathroom were conditioned too much. There are situations in which bypass is not feasible. This simply is an alternative.

 

[beenthere]

Motorized static pressure controlled bypass is best with VS blower.

Don't take this wrong. But, you have a strange zone layout.
Most people prefer that their kitchen be on the same zone as their dining room.

Where will you locate the stat for the Kitchen, bathroom, small bedroom zone?

 

[Miller257]

keep in mind it's a small 950 sq foot ranch. the "living room/dining" room is one room. the stat will be in the small bedroom (my bedroom). the kitchen and bathroom are pretty small. they are also on the same zone because in a few years i want to add onto the house, and the bathroom and small room will become a large room, and it will be very easy to adapt the ductwork. then ill add a second furnace,ac and zone system to take care of the new master bedroom, kitchen, 2 bathrooms and dining room.

all the work i'm doing to the house, i'm trying to "future proof" so i don't have to rip stuff apart in a few years when i get hitched and start having kids.

i also want to steer away from a dump zone, besides superior comfort control, i also want to reduct conditioning costs. drop the temp down in the office/living room at night and only heat the bedrooms. etc...

 

[beenthere]

Is the A/C going to be 2 stage also?

What are the CFMs per zone?

Future proofing a system. Can often lead to problems before the future arrives.

With the living room/dining room being one room. Thats even more of a reason for the kitchen to be on that zone.

The 2 bedrooms and bathroom would work better on the same zone.

With your current plan. You have to condition the small bedroom during the day, to condition the kitchen. And of course, you will still be conditioning the kitchen at night time, in order to condition the small bedroom. Which means you will be drawing in air from the return source for the kitchen area. And going into loner run cycles. Since the return source for the kitchen would be a return in an area other then the kitchen itself.