Amana or York?

[beenthere]

Beware of contractors that don't use 2 stage stats on 2 stage furnaces that can take advantage of a 2 stage stat.

[snamin]

Beware of contractors that don't use 2 stage stats on 2 stage furnaces that can take advantage of a 2 stage stat.

Any particular reason why? I double checked with the Amana guy. He said the decision which stage to use is made by the control board inside the furnace. All the control board needs to get from the thermostat is the temperature on the main floor.

[beenthere]

The thermostat doesn't tell the board what the temp in the house is. It simply tells teh furnace to run or not, and in the case of a 2 stgae thermostat, what stage to run in.

The idea of 2 stage is long run times to improve comfort.
By using the board. You lose a lot of that long run time. It just uses a timer. May or may not have some logic on that board. that might kick second stage in faster because it ran for X minutes last time.

Using a 2 thermostat. The furnace won't go to second stage unless needed.


Often times, with a single stage stat, when it gets a little colder out. The furnace goes into second stage for ½ a minute or so, at the end of the cycle needlessly. Because the timer timed it on.

[seatonheating]

The thermostat doesn't tell the board what the temp in the house is. It simply tells teh furnace to run or not, and in the case of a 2 stgae thermostat, what stage to run in.

The idea of 2 stage is long run times to improve comfort.
By using the board. You lose a lot of that long run time. It just uses a timer. May or may not have some logic on that board. that might kick second stage in faster because it ran for X minutes last time.

Using a 2 thermostat. The furnace won't go to second stage unless needed.


Often times, with a single stage stat, when it gets a little colder out. The furnace goes into second stage for ½ a minute or so, at the end of the cycle needlessly. Because the timer timed it on.

Hey Been,

Someone correct me if I'm wrong, but I don't think that I am. I believe Goodman/Amana 2 stage furnaces(which they all are now) have to run off of a single stage thermostat. They are designed this way with only a W terminal, no W2. This is performed via a dipswitch in the furnace which is field selectable. I believe the internal board does have some decent logic to it, it isn't just a timer.

[beenthere]

Depends which model.
The lower end models can't use one. The higher end can I think.

I forgot about that though.

[amd]

Can't I solve this by closing or partially closing registers in the living room where the thermostat is installed?

Doing so will just make the living room colder than other areas; the furnace will simply run more and overheat the rest of the house.

By the way, the Amana guy said that the old (non-digital round type) thermostat is okay and I don't need to replace it. I'm just wondering how the 2 stage Amana furnace will know which stage to use if the thermostat doesn't tell it. The York guy was positive that I need a new thermostat.

See beenthere's post.

.................................................. ..............
The AMH just uses a timer for staging and should be avoided - get the AMV.

[snamin]

Thanks very much to all of you.
I've decided to drop Amana. Another guy came in. They sell Bryant, Rheem and Trane. He said Amana uses 4 ton blower (I hope I got that correctly) and with my ducts, which by his opinion are small, it will cause a lot of noise. That may or may not be true but I'm at the point that I need to decide (or I will be chosing for the whole winter ). So Amana is out. I'm still waiting for another York contractor to come in a few days. Over the phone, he suggested the modulating model. Other contractors expressed opinion that modulating will not work with small ducts because they need near to perfect return air flow.

[beenthere]

While the Amana you were quoted does have a 4 ton blower(max size A/C the furnace should be used with).
It would be set up for the air that the furnace needs for its heating BTUs.
Not just set to move max air flow.

A modulating furnace will work ok on less then perfect duct. The same as any 2 stage, or single stage furnace will.

Your getting some BS contractors to give you estimates.

[snamin]

While the Amana you were quoted does have a 4 ton blower(max size A/C the furnace should be used with).
It would be set up for the air that the furnace needs for its heating BTUs.
Not just set to move max air flow.

A modulating furnace will work ok on less then perfect duct. The same as any 2 stage, or single stage furnace will.

Your getting some BS contractors to give you estimates.

I have to say the contractors I'm speaking with don't impress me. I've got 5 quotes so far. All the contractors promoted their products and refered nagatively (directly or inderictly) to the other brands. All the contractors were against the heat loss calculation basing their decisions on the "decades of experience". I can't seem to find a good contractor in the Toronto area.

[amd]

Keep on getting quotes until you find a good contractor; might have to go through 10+ companies to get someone decent.

[beenthere]

Screen them over the phone. Don't do load calcs, no reason to come out.

[snamin]

Screen them over the phone. Don't do load calcs, no reason to come out.

Apparently, we have different standards in Canada. I was told by all the contractors that it's not a common practice. One of them actually told me "how many sizes are out there anyways? 45k is too small for you. That means you're between 60k - 80k and you can't miss that much going with any furnace in that range". Another York contractor coming in today said he can do the load calculation but it's not part of the free estimate service and it will cost me $. How hard is it to do Manual J? It seems I can download it for 50$. Can a non-professianal like me do it?

[beenthere]

How many sizes?

40k, 45k, 50k, 60k, 70k, 75k, 80k, 90k, 100k 105k, 110k, 115k, 120k. So atleast 13.

Its not that hard to do a manual J. Its worth while to do your own.

And Canada also has its own load calc method known as F280 as I recall.