Waterfurnace aux heat problem

Discussion in 'General Discussions' started by dpwct, Oct 30, 2013.

  1. dpwct

    dpwct New Member

    We have a waterfurnace geothermal system installed the aux heat seems to be going on even when thermostat is set to just 1 degree above current room temp - In other words aux electric heat is going on instantly (when only compressor should be on) further more the thermostat display shows stage 2 not Aux.

    Checked all settings and wiring and everything looks ok. Any thoughts on cause - could it be faulty thermostat.

    Specs - circa 2010
    - WaterFurnace Envision model NSZ022 split unit
    - WaterFurnace air handling unit model # NHA022A0501R 5kw heat strip
    - TP32U03 Thermostat
     
  2. geoxne

    geoxne Active Member Forum Leader

    The instructions for that thermostat is here-
    http://www.waterfurnace.com/thermostats/TP32U03-5.pdf

    Operation of the system is determined by installer settings. If it is setup to defaults and recommended settings for your equipment, Stg 2 indication could mean only a higher blower speed (with single stage compressor).

    If you are absolutely certain aux electric heat is coming on prematurely check for the following settings-
    -Differential- degree separation between stages
    -Smart Heat Staging- aux heat time delay none to 60 min.

    Also check
    -Display Options-Aux Heat Display-On or Off

    Warning please read page 4 NOTE under Installers Setting about end users ... equipment stop working...void the warranty!
     
  3. dpwct

    dpwct New Member

    ----
    Yes the technician checked and verified with an amp meter that electric heat was on prematurely (when stage 2 displayed)
    What do you suggest for settings for

    -Differential- degree separation between stages
    -Smart Heat Staging- aux heat time delay none to 60 min.

    As for blower speed I believe there is only 1 blower speed on this model - do you know if that is correct
     
  4. geoxne

    geoxne Active Member Forum Leader

    I suspect in your case Y2 is jumped out to W or W2 some where between the tstat , airhandler and compressor control board.

    The quickest remedy without rwould be to change STG2 differential to retard STG2 call-
    -Installer Settings- follow instruction guide
    -Differential-Enter-1ST Stage-0.5-Enter-2ND Stage-1.5-Enter-Previous-Home

    A Stage2 differential of 1.5 as above will not allow a Stage2 call until room temp drops 2 degrees (Stg1diff+Stg2diff) below set point (adjust to your balance between comfort and electric heat cost).

    Your NHA022 has a ECM blower and is configurable for adjust speeds for G, Y1,Y2 and Aux.
     

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