Question on 2 Speed Furnace (also called dual stage I think)

Got a newfangled high efficiency furnace, has 2 speeds. When on full, no problem, pumps lots of hot air out the ducts at 118 to 127 degrees.
However on low speed, it just pushes air at ambient tempature through the ducts. I put a thermometer in the duct, and the air moving is usually about 2 degrees cooler than the room temperature. Clearly in low speed the blower is running, but air is not being heated.
Am I wrong, I thought in low speed the air is still supposed to be warmed?
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Yep the air is supposed to be heated, just doesnt blow as hard.
Sounds like either the normal (lower) stage isnt working or the guy who wired it up didnt do it right. (make sure the themostat isnt on fan before anything else)
Tom
snipped-for-privacy@gmail.com wrote:

full,
degrees.
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This is a guess... but - do you know, for certain, that you had a 2 stage thermostat installed? When they put my 2 stage system in, they never bothered to change the thermostat, and simply set dip switches on the board to have the furnace kick into high speed if the low speed had been running for 5 minutes or so.
Reason I ask is - your furnace may be set up to only run at high speed, and then it kicks into low when the burners shut off.
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Good question... I don't know. I picked up an expensive one for about 60 bucks at Costco about 6 years ago when I wanted a timer one, and installed it myself.
A furnace company put in the 2 stage Furnace a month or two ago.. .they didn't change thermostats. Is there anything I should look for on the Thermostat? I am pretty certain it is a Honeywell, don't know model number. Just one of those that have the timer..with a lot of settings.
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It's almost assured that you don't have a dual stage thermo. I'm not an HVAC guy, not even close... but if your thermostat is 6 years old, and they didn't replace it or rewire it - I'd bet your system was not installed properly.
It seems ridicuosly common for new install of dual stage systems to not be put in right. I've no idea why this is. But in order for you to truly get what you paid for, and the benefits of dual stage heating - you need a dual stage stat.
I'd call the company up, ask why they didn't install a 2 stage stat, and get them back out to finish the job properly. I'm sure an HVAC tech will jump in here soon with other advice. Bubba, you out here?
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Yup. Same here. A two stage furnace gets a 2 stage stat, PERIOD! You didnt tell the installers that you wanted to keep that $60 thermostat, did you? Get it done right or dont spend the extra money on a 2 stage furnace. Bubba
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My guess is that the guy quoted me a flat price.. 4k for furnace and AC, and didn't want to eat the price of a new t-stat. It never came up, I didn't know I would need a new one, or I certainly would have had him put a new one in... even if I had to eat the cost.
Anyway I called them and they are coming out tormorrow to look at it... seems like that follow up call will cost them a bit of money, and they would have been wise to do it correctly the first time.
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Just thought of a follow up Q--- should I just go out tonight and buy a quality 2 stage T-stat (since i do want the timer functions, so it auto-turns down at night, etc) and leave it for the guy to install, so he doesn't put junk in without a timer... and I don't have to come back later to put a nicer one in.. and possibly screw up the wiring in the process?
If I do pick one up at costco.. will it be clearly marked as a 2 stage?
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Good luck finding a two stage stat! You may find one of the new Honeywell 8000 series, touch screen, stats that will control a two stage, but I think a two stage stat at your local home center may be a bit of a rarity. If you find one it will be indicated for two stage, or labeled for two heat, two cool.
Most two stage furnaces will run on a single stage stat, but they will run better on a two stage stat. Greg
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I had a new furnace put in last year. Every proposal included a new thermostat, even though the old one was fine. They just didn't want to foul up the job with old stuff. They even replaced all the gas pipes and valves.
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Most two stage furnaces can be setup to work on a single stage stat or two stage stat.
In single stage mode the lower stage runs for a set time and if there is still a call for heat, the high stage is energized until there is no call for heat.
I like the single stat mode better because, if the stat is turned up in mild weather the second stage isn't energized.

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and if you set it back on a cold night you can have up to 15 mins before it ever starts to get warm. That can seem like an eternity on a cold cold morning. Do it right the first time. Bubba
On Thu, 17 Feb 2005 03:13:21 GMT, "Terry"

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