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Thread: FHP Geo problem

  1. #1
    Join Date
    Jul 2008
    Location
    Florida Panhandle
    Posts
    25

    FHP Geo problem

    Morning,
    I've been fighting a Florida Heat Pump (FHP) in my rental with no luck.

    I'm far from proficient with Geo but I have assisted with pond loops installs, equipment installs, and a hand full of simple service calls.

    Currently only getting 10-12 degree drop in air temp across the Evap.

    Model # gt018. Mounted in attic
    Closed loop,
    Single water pump mounted above package unit (highest point of the loop system, seems like a bad idea to me for fear of any air going up and damaging pump but I don't know..?)

    Loop temp entering unit is around 90 degrees and 95 coming out. + or - 5 degrees depending on time of day. Low to mid 90 out door ambient temp at time of testing.

    I forget exact loop pressures but it was lower than suggested minimum in installation manual, around 4 and 12psi (guesstimate) FHP tech support told me I'm getting 8-10 gpm flow based on the pressure / temp readings I gave him.

    Evap and blower wheel are clean, all amp draws checked out fine.

    All this information and than some was given to FHP Tech Support.
    Says all is fine and believes its either a bad txv or bad reversing valve....

    I'm not confident that will solve the problem and try not to make a habit of changing out parts when there is no need to

    TXV is non adjustable and worked as it should when bulb was placed in ice water and when held in my hand.

    Reversing Valve is working fine, The "problem" tech support is point out is it showed a 4 degree temp difference on opposing vapor lines, the warmer of the two is ran and insulated together with the two liquid lines that run through the reversing valve.

    Your ?

  2. #2
    Join Date
    Jul 2008
    Location
    Florida Panhandle
    Posts
    25
    76 views and no incite at all?

    Back to the top!

  3. #3
    Join Date
    Dec 2012
    Location
    Nashville, TN
    Posts
    48
    Stupid reply time: You say this is a Florida install so I may be way off base as it might not even have axillary heat, but if it does make sure you don't have a strip powered. And be sure to test for a shorted to ground strip by taking amp readings from each power line feeding the axillary strips.

  4. #4
    Join Date
    Dec 2012
    Location
    Nashville, TN
    Posts
    48
    Quote Originally Posted by HighlandThunder View Post
    Stupid reply time: You say this is a Florida install so I may be way off base as it might not even have axillary heat, but if it does make sure you don't have a strip powered. And be sure to test for a shorted to ground strip by taking amp readings from each power line feeding the axillary strips.
    Stupid reply reply, Florida heat pump - is that the brand and not the state?

  5. #5
    Join Date
    Jul 2008
    Location
    Florida Panhandle
    Posts
    25
    Florida is the brand as well as the state the unit is located. No auxiliary though....

  6. #6
    Join Date
    Sep 2002
    Posts
    13,551
    Dooood! Maybe toss me a clue or two ?
    How about if you post a full set of diagnostic readings?
    Say;
    Pressures from every gauge access port.
    Temps of the lines at those same points.
    Temps of the four lines at the RV
    SC?
    SSH?
    entering and leaving air temp?

    PHM
    ------



    Quote Originally Posted by MichaelDinPC View Post
    Morning,
    I've been fighting a Florida Heat Pump (FHP) in my rental with no luck.

    I'm far from proficient with Geo but I have assisted with pond loops installs, equipment installs, and a hand full of simple service calls.

    Currently only getting 10-12 degree drop in air temp across the Evap.

    Model # gt018. Mounted in attic
    Closed loop,
    Single water pump mounted above package unit (highest point of the loop system, seems like a bad idea to me for fear of any air going up and damaging pump but I don't know..?)

    Loop temp entering unit is around 90 degrees and 95 coming out. + or - 5 degrees depending on time of day. Low to mid 90 out door ambient temp at time of testing.

    I forget exact loop pressures but it was lower than suggested minimum in installation manual, around 4 and 12psi (guesstimate) FHP tech support told me I'm getting 8-10 gpm flow based on the pressure / temp readings I gave him.

    Evap and blower wheel are clean, all amp draws checked out fine.

    All this information and than some was given to FHP Tech Support.
    Says all is fine and believes its either a bad txv or bad reversing valve....

    I'm not confident that will solve the problem and try not to make a habit of changing out parts when there is no need to

    TXV is non adjustable and worked as it should when bulb was placed in ice water and when held in my hand.

    Reversing Valve is working fine, The "problem" tech support is point out is it showed a 4 degree temp difference on opposing vapor lines, the warmer of the two is ran and insulated together with the two liquid lines that run through the reversing valve.

    Your ?
    PHM
    --------
    The conventional view serves to protect us from the painful job of thinking.

  7. #7
    Join Date
    Jan 2014
    Posts
    20
    First question. At the end of your post you mention the techs "problem", are you describing how the 3 lines on the suction side of the reversing valve are insulated together? Or something else entirely.

    And second the psi readings seem fairly low on the ground loop side. Below 20psi most water/ref coaxial heat exchangers will start to lose thermal conductivity. Also for a 1 1/2 ton water/air heat pump, 10-12 gpm seems very excessive. Almost 3 times what most manufacturers of geothermal systems recommend for proper operation. Taking all this in, the low pressure of the ground loop with the high water velocity in in the coax would cause even worse thermal transfer, and most probably poor performance.

  8. #8
    Join Date
    Mar 2009
    Location
    Triad - North Carolina
    Posts
    441
    A 90 degree ground loop is not too good either. Design temp is much lower. Typical ground loops normally around 50
    Yes, I've seen that before and it doesn't mean I like it.

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