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New HVAC Unit Seemingly Questionable Forced Decision

jamesd123787 Member Posts: 1
edited January 2021 in Gas Heating
We purchased two brand new hvac units 10 months ago. Today was our first cold snap and the heating unit took 5+ hours to heat 3 degrees warmer. We called the company who installed and he forced two options on us. Force the unit to only heat stage 2 (most air) or allow it to try to use both cycles (it's not hitting stage two) and have it take hours upon hours to heat the house. To me this seems wrong. Just because the unit doesn't have error codes doesn't mean the unit is working correctly. The thermostats checked out. Trying to understand why purchasing two brand new units we are forced between inefficient heating (disabling two cycle/stage) or having the unit not heat the house when it's cold out. Doesn't add up to me. I will gladly add unit details, square foot, etc if needed.


    EBEBRATT-Ed Member Posts: 13,101
    Sounds to me like you have a 1 stage thermostat. When the unit was installed they should have installed a two stage thermostat.

    If they did not install a two stage thermostat have one put in. If the units are the correct size nothing is wrong your just not allowing it to run at full capacity and you should
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 4,917
    edited January 2021
    Agree with @EBEBRATT-Ed at first glance. Would need more information about the make and model of each piece or equipment.

    Thermostat model number
    Outdoor unit model number
    Indoor air handler/furnace model number *
    Part number of heat package, If there is an auxiliary heater included in the air handler
    (* unless this is a one-piece package unit where the ductwork is connected to the outdoor unit in some way)

    A picture of the thermostat may be enough to let us know the type of thermostat you have.
    Pictures of the manufacturer's label are sometimes easier than typing all the letters & numbers.

    This information will help us to determine if the proper thermostat is installed with your equipment.
    Edward Young Retired HVAC Contractor & HYDRONICIAN Services first oil burner at age 16 P/T trainer for EH-CC.org
  • Ironman
    Ironman Member Posts: 7,062
    It's not a matter of having it EITHER first stage or second. You should have it setup with a 2 stage thermostat as Ed mentioned. That way, if the first stage can't keep up, it will automatically go to the second (high) stage.

    It appears that you're using setback which will compound the issue. That doesn't really save any energy with a multi-stage unit. Just set the stat at one temp and leave it there.
    Bob Boan
    You can choose to do what you want, but you cannot choose the consequences.
  • motoguy128
    motoguy128 Member Posts: 394
    Most 2 stage furnaces will allow timed autostaging which I think really works just as well.  Most of the time 1st stage is plenty except deep setbacks or 1% coldest weather.  

    Two stage thermostat end up being programmable and we find a lot of our clients just want a very basic thermostat, so again 1 stage only.  Plus pulling new wire isn’t always practical.  

    5 hours to raise 3f would be normal and a properly sized system if at design conditions and windy.  Plus older homes lack the ductwork for oversized equipment that most people are used to in low mass newer construction.