Single stage thermostat with 2 stage furnace

[harvest644]

I just had a Amana AMV9 2 stage varible speed furnace installed today. All the work looks very well done except they installed a single stage thermostat. Doesn't this defeat the purpose of the 2 stage furance?? I wasn't here when the tech finish the installation and my wife had no idea was to look for. The salesman didn't give me any thermostat choices when I got the estimate. Should I request that they install a 2 stage thermostat??

[trey r]

Yea I would say that probably defeat the purpose. Get a 2 stage stat.

>>>edit... removed caps


[Edited by jultzya on 11-09-2005 at 10:05 PM]

[Chad711]

Some units go to second stage via the control board too, depends on what you have. What Im saying here is your 2 stage furnace will still work in many cases.Not sure on that brands specs.

[harvest644]

I read the owners manual and it states that you can use a single stage thermostat, It will will be on low stage for 5-10 min depending on the DIP switch settings. I think they should have at least offered or told me which type thermostat they were going to install. Do you have to add extra wiring for a 2 stage thermostat?? The old furnace was installed in the 70's...

[trey r]

Yea some do go to second stage after X amount of run time based on unit, I’m a Trane guy so I’m not 100% sure but I don’t think that furnace does.

>>>edit... removed caps


[Edited by jultzya on 11-09-2005 at 10:07 PM]

[superfittertech]

yes you need an xtra wire for a 2 stage stat. That's probably one reason why they didn't offer it. Single stage stat will be fine as that furnace does have a timer in it that will bring on the second stage after 5-10 minutes of operation on 1st stage. If your furnace is sized right (by using the manual J) a 2 stage stat is unnessary.

[BaldLoonie]

horsehockey

Regardless of sizing, get a 2 stage stat. The idea of 2 stage furnaces is to have a long run cycle on a quiet, gentle low fire. Kinda like you do in your car. You don't have an on-off switch you toggle as you get cold and turn off when you get hot. You find a nice gentle warmth and are very comfy. You can do that with a 2 stage stat but not with a timer. The timer won't allow it. Period. I put my 2 stage in during a cold snap. Didn't have the 2 stage stat yet. That poor furnace couldn't decide what to do. With the "right" stat, it would have run & run on low. Inaudible and very comfortable. Instead it would come on low, run 10 minutes then switch to high. But that would immediately satisfy the stat and turn off. A few minutes later, it would repeat with constant cycles.

[harvest644]

Thanks for the Info, I think I'll get them to installed a 2 stage stat.

With the 2 stage stat can you set the fan to be on at low speeds at all times?? With this 1 stage you per the manual you get the fan on at 56% of the high stage cooling. It seems to be blowing more air than my old furance with the fan setting on. If thats 56% of the max airflow I think my house will feel like a wind tunnel at 100%....

Thanks for the help...

[chicago tom]

did they leave the installation papers with you or just the owners manual?Check the manual for 2 stage operation with a single stage stat.

I install heil furnaces and a two stage furnace will work with a single stg. stat by turning the #4 dip switch on the board to the off position.The system fires on high for about 1 min.then it switches to low fire for 12 mins.before changing back to high.

Turn your heat on and stand by the unit to see if it switches.

[Jultzya]

2 stage equipment deserves 2 stage controls!

If not, why did they ever invent the two stage stat?

[gje1]

2 stage t-stat are nice and very expensive. You can see by some posts, that some recommend a 2 stage t-stat. Yours should run fine on a single stage t-stat. See your owners manual and makse sure it doesn't state you need a jumper (bridge) between W1 and W2 for it to go to high fire. The time between firing will determine the make of the furnace.

[mayguy]

Go two stage stat.

My parents built a new house last year, and they cheap out on a single stage t-state on the XV90 Trane.. It did ok with the timer. but it never ran long enought to make the basement comfortable..

So I put in a Vision Pro two stage in for them this fall, and Mom said she already seen the comfort in the basement already.. She glad that I talked her into doing the two stage stat. Now she don't have to worry about dad freezing to death.

[Jultzya]

Originally posted by gje1
2 stage t-stat are nice and very expensive. You can see by some posts, that some recommend a 2 stage t-stat. Yours should run fine on a single stage t-stat.

By your theory, he should have saved money and purchased a single stage unit.

I will say that ALL of my new clients that have purchased a two-stage stat from my company (beings that they got a single stage stat with their equipment "installed by others") have been VERY happy with the improved results.

Can't beat client feedback.

[Collin]

If it is easy to run a new wire from the stat to the furnace then absolutely he should get a two stage stat.

Now what if there is 40 feet of wire through two finished floors?
Got a magic fish tape?

[Jultzya]

There are several ways around fishing new wire.

[Jultzya]

Before you ask "what are the different options"?

Here is a thread that lists some of them.

[Collin]

As long as the original poster understands there are COSTS associated with upgrading to the two stage stat then all is well.

[curry]

i think this thread just caused tha HOs Amana contractor

some unjustified grief.

I got the feeling that the HO thinks we just handed him a mandate to go medeval on his installing contractor.

But i would just say that he should discuss it with the guy, not demand it because of opinions from this thread.

We don't know what the circumstance were on the sale.

We all have been there so you don't have to read between the lines to know what I am saying.

Could be impossible to run a new wire and the sales guy
just didn't mention it.

I don't care how good a tech is, there are some conditions that won't let you run an new line.




[Edited by curry on 11-10-2005 at 12:40 PM]

[superfittertech]

another option is fast-stat.com
you can add 2, 4, or 6 etra wires. I used one where customer only had 2 wires, (heat only)we used fast stat 5ooo & bumped it up to 6 wires for cooling & humidification.

[jumpit]

Get the two stage, because if you do not need to have hi stage on it won't. Two stage is really designed for two stage stat for better comfort.I do not understand why someone would have a two stage furnace and not have the two stage stat?