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  1. #1
    Join Date
    Dec 2019
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    Heat pump pressures

    I just installed a new heat pump unit 410a air handler has a new evaporator coil my pressures in cooling mode are 90 on suction 200 on head 60 degree outdoor air temp when in heat pump mode pressure is 115 suction 425 head filters are clean all vents are open blower speed on high do you normally see a higher head when in heatpump mode

  2. #2
    Join Date
    Mar 2019
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    Well the head pressure is related to what the indoor return air temp is in heating mode . Without knowing what that indoor temp is it is hard to say if your head pressure is excessive or not .


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  3. #3
    Join Date
    Jan 2010
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    Is it a matched system ?

  4. #4
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    Dec 2019
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    Thread Starter
    Indoor air temp is 70 degrees

  5. #5
    Join Date
    Mar 2019
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    Then yes I would say that the head pressure is a bit excessive . Usually you will have a condensing temp over ambient of 30 to 40 degrees in heating mode which would be your indoor temp because the evap coil is now your condenser in heating mode . So if you have 70 degrees as your return temp you would be looking somewhere in the range of 318 - 366 psi . Issues that cause low suction pressure in the summer are the same issue that will cause high head pressure in heating mode . Is the return filter really restrictive ? Do you have the proper size return ?


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  6. #6
    Join Date
    Dec 2019
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    Thread Starter
    It has 2 20x20 filters with a 20inch return duct 5 ton system

  7. #7
    Join Date
    Dec 2019
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    Thread Starter
    When unit first comes on in heat pressure is 100/300 after about 1 min ot slowly climbs to 115/425

  8. #8
    Join Date
    Dec 2019
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    Thread Starter
    I would recover some refrigerant but in cool mode it seems low already 90/200

  9. #9
    Join Date
    Jan 2014
    Location
    New England
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    Sounds like you just replaced the OD unit? as you mention you replaced the coil in the Air Handler? Yes/no? If yes then you probably have a Frankenstein system to a degree. What’s the brand and model number of the OD unit and brand and model number of the ID unit. What’s the age of the Air Handler?

  10. #10
    Join Date
    Oct 2011
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    Gladstone, Oregon (Portland)
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    Did you weigh in the charge? How did you go about things on initial startup? What was the SH and SC?

  11. #11
    Join Date
    Jan 2004
    Location
    PA
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    Sounds a bit like low indoor air flow.

    2-20x20 air filters is small for 5 tons.
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    How many times must one fix something before it is fixed?

  12. #12
    Join Date
    Mar 2018
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    Kansas Flatlands
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    As Bazooka Joey asked, Is it a matched set? If so, you have references to go to PT charts etc. If not matched, You can "expect" issues in the heat mode. Anybody can make it cool, but can you keep it going in heat mode. 60 degrees ODT has a lot of heat to pick up and pressures gonna run high.

  13. #13
    Join Date
    Aug 2002
    Location
    Southold, NY
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    Why are you operating in heat mode with 60° ambient?

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