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  1. #1
    Join Date
    Jun 2005
    Posts
    23
    I'm assuming I know the answer to this, but guess what happens everytime I assume??

    I'm looking at some Carrier literature and the blower speeds for Infinity 80, Performance 80 and Comfort 80 series are variable(I get what that is) for Infinity, 4-5 for Perfomance and 3-4 for Comfort. Could someone clarify that for me?

    I currenty have a 19 year old single stage furnace. 17 years ago when the air conditioner was bought, a 2 speed fan (blower?) was put in the furnace, and it runs 24/7. I love it. I'm looking at a new furnace and air conditioner, and I'm trying to decide if I need a two stage furnace. I'm quite comfortable with the single stage, and besides I wonder if the 2 stage is even smart. When my current blower is on low speed, I can barely feel air coming out of the upstairs supply vents. When the furnace kicks in, the blower speed picks up and it's all good. When a 2 stage is working in first stage, what's the deal with the blower? Is it operating at low speed? Would I be getting enough heat upstairs, where my office is, and where I spend most of my day? Hence we go back to my original question about the 4-5, and 3-4 blower speeds!

    Thanks for you insights!
    L-J


  2. #2
    Your comfort and performance series furnaces (80% or 95%) use a regular AC blower motor. They run on high speed for cooling, and medium speed for heating and fan-on modes.

    Your infinity series furnaces (80% or 95%) use a DC blower motor. This motor is more reliable and uses 90% less electricity than its counterpart. A series of algorithms will be calculated within the controls of your "infinity" system (the circuit board, blower motor, infinity control, etc) that will calculate the ideal speeds to run at for temperature, humidity, and comfort. This blower will run at whatever speeds it deems necessary and will be quieter and more comfortable than its counterparts. Basically, it's smart technology.

    I hope this has answered your question.

  3. #3
    Join Date
    Feb 2005
    Location
    Toms River, NJ
    Posts
    419
    I just went through the same issue with one of my customers. I will tell you her story, her name is Linda. Linda has a cape and on the second floor the air flow is very week with her existing furnace which is about 20 yrs old. Linda wants to replace her furnace but is undecided about getting a single stage versus a two stage. You see a two stage will begin on "low fire" and the blower speed will be at the lowest setting. This is done for many reasons,but the most important reason is to maintain a certain temp rise. The problem is that Linda has a poorly designed duct system and if she were to purchase a two stage furnace, she would get virtually no heat upstairs, until the furnace went into "high fire" where the blower speed is increased. The problem is that more often than not, the furnace will not see "high fire" and the result will be a cold second floor. I suppose one could argue that heat rises and everyting but when bedroom doors are closed all bets are off. I told Linda that she would be better off with a single stage furnce..I actually sold her a Carrier 90+ comfort series furnace. In a perfect world, one could correct the duct work but this is very invasive and costly. The two stage furnace is great but if you have a poorly designed duct system it better to stay away....
    Hope this helps.

    Dave in NJ

  4. #4
    Originally posted by smadave
    I just went through the same issue with one of my customers. I will tell you her story, her name is Linda. Linda has a cape and on the second floor the air flow is very week with her existing furnace which is about 20 yrs old. Linda wants to replace her furnace but is undecided about getting a single stage versus a two stage. You see a two stage will begin on "low fire" and the blower speed will be at the lowest setting. This is done for many reasons,but the most important reason is to maintain a certain temp rise. The problem is that Linda has a poorly designed duct system and if she were to purchase a two stage furnace, she would get virtually no heat upstairs, until the furnace went into "high fire" where the blower speed is increased. The problem is that more often than not, the furnace will not see "high fire" and the result will be a cold second floor. I suppose one could argue that heat rises and everyting but when bedroom doors are closed all bets are off. I told Linda that she would be better off with a single stage furnce..I actually sold her a Carrier 90+ comfort series furnace. In a perfect world, one could correct the duct work but this is very invasive and costly. The two stage furnace is great but if you have a poorly designed duct system it better to stay away....
    Hope this helps.

    Dave in NJ
    Absolutely agree. Just got this lecture from one of the trainers at Carrier as a matter of fact.

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