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  1. #1
    joshbloomberg's Avatar
    joshbloomberg Guest

    Problems with LG split heat pump M/N LS902hpv



    I'm a maintenance tech., not a certified HVAC tech., though I do have my E.P.A. certification. That said, I installed a new LG heat pump m/n LS902HPV in my friend's 400 sq.ft. shed, which he converted to a music-practice room (I warned him that having me install the unit would void the warranty: I brazed in a 3/8 inch schrader tee port to avoid trying to purchase the gauge port coupler). The unit ran well in air conditioning mode on the day I installed it, as it was warm outside. On the first cold day (35 degrees F.), I tested the heat. When I set the setpoint at 84 F., the symbol on the remote was the flame icon, while the blower unit's display offered a defrost icon. The blower unit ran on low speed for 30 seconds and then stopped. The outdoor condenser never ran. I tried all means of resetting the entire unit, including pulling the 240V disconnect. The unit supposedly runs a self-diagnostic for thermistor errors, but nothing came up on the screen. Additionally, when I checked for the ambient temperature on the remote, I received a reading of 74 d. F., while the indoor's ambient was as cool as the outdoor's. Is the temperature sensor in the remote or in the blower unit? I successfully ran the cooling mode (and it was cooling, even with an ambient as low as 40), but nothing I did would bring on the heat. What's probably wrong?



  2. #2
    Join Date
    Oct 2008
    Location
    mallorca, spain,
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    75
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    Re: Problems with LG split heatpump LS902HPV

    hi josh, was the unit pumped down so you could transport it ? did you use OFN in the pipwork when you brazed it? was it pressure tested ? was it vaced out?
    sorry did not understand you had to braze a 3-8 schrader tee?
    come back with some more facts please . sedgy

  3. #3
    joshbloomberg's Avatar
    joshbloomberg Guest

    Re: Problems with LG split heatpump LS902HPV

    Sedgy,
    This was a brand new install. I installed the schrader tee to avoid having to purchase the pressure gauge port adapter needed to interface between the charging port on the condenser unit and my standard charging manifold hoses (there is only one charging/evacuating port on these units so far as I can tell -- on the 3/8 inch suction side... no port on the 1/4 inch high side). You have to be a licensed HVAC rep. to purchase these adapters, which I certainly am not. The unit was pressure tested with nitrogen and throoughly evacuated based on the directions in the manual (though how this is accomplished without a high side port is beyond my comprehension). Anyway, the sealed system is fine; it's the controls, particularly the remote thermostat or the thermistor chip on the blower, that are causing me grief.
    -- Thanks, Josh

  4. #4
    Join Date
    May 2005
    Location
    newbury
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    43
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    Re: Problems with LG split heatpump LS902HPV

    If I remember correctly there is an icon that looks like a flame or tear drop to denote dehumidification mode. This may look like a flame and is probably not heating mode. What you are looking for is a sun icon. If you don't have this you may have a cooling only unit. Check the outdoor unit for a reversing valve. Roger

  5. #5
    joshbloomberg's Avatar
    joshbloomberg Guest

    Re: Problems with LG split heatpump LS902HPV

    Yes, this unit is in fact a heat pump. It has a reversing valve and a three way valve between the condenser unit and the evaporator. I was able to get the unit into heating mode several times, but for some reason (electronic glitch?) it will now not go directly into heat. It insists on going into defrost -- but only according to the display. The indoor fan runs for thirty seconds and then stops, and neither the condensor fan (which you would expect to not run in defrost) nor the compressor runs. Is this a problem with the blower board or with the remote? The unit performs, according to its instructions, a thermistor self-diagnostic. Why then does it read a ambient temperature of 76 degrees (F) when the actual temperature is more like 40?

  6. #6
    joshbloomberg's Avatar
    joshbloomberg Guest

    Problems with LG split heat pump M/N LS902hpv

    I first posted this message in "New to RE":
    I'm a maintenance tech., not a certified HVAC tech., though I do have my E.P.A. certification. That said, I installed a new LG split system heat pump m/n LS902HPV in my friend's 400 sq.ft. shed, which he converted to a music-practice room (I warned him that having me install the unit would void the warranty: I brazed in a 3/8 inch schrader tee port to the suction side right above where you make the flare because I was not able to purchase the charging/evacuation gauge port adapter). The unit ran well in air conditioning mode on the day I installed it, as it was warm outside. On the first cold day (35 degrees F.), I tested the heat. When I set the setpoint at 84 F., the symbol on the remote was the flame icon, while the blower unit's display offered a defrost icon. The blower unit ran on low speed for 30 seconds and then stopped. The outdoor condenser never ran. I tried all means of resetting the entire unit, including pulling the 240V disconnect. The unit supposedly runs a self-diagnostic for thermistor errors, but nothing came up on the screen. Additionally, when I checked for the ambient temperature on the remote, I received a reading of 74 d. F., while the indoor's ambient was as cool as the outdoor's. Is the temperature sensor in the remote or in the blower unit? I successfully ran the cooling mode (and it was cooling, even with an ambient as low as 40!), and for some reason the heat did come on once, and with a very substantial output, so I know that the reversing valve works. Now, however, I'm stuck: nothing I do will bring on the heat. What's probably wrong?

    Thanks, Josh

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