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  1. #1
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    Extra Charge - Heat Pumps



    Hi All,

    How can we compensate for the extra charge that we need in cooling mode, for the heating mode?



  2. #2
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    Re: Extra Charge - Heat Pumps

    Hi jwasir
    I had a unit last month with a similar problem - it is water cooled so I reduced the water flow rate so as the load was reduced which worked. If it is air cooled/heated the outdoor fan could be slowed or airflow reduced with a damper.

  3. #3
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    Re: Extra Charge - Heat Pumps

    I have same question and want to know the answer.

  4. #4
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    Re: Extra Charge - Heat Pumps

    Why do you need to compensate and why you think you need to compensate for this?
    Charge is the same in cooling and heating mode because mass flow is the same under standard conditions. Excess due to deviating load, ambient, indoor, fan speed...is stored in receiver and condenser.
    It's better to keep your mouth shut and give the impression that you're stupid than to open it and remove all doubt.

  5. #5
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    Re: Extra Charge - Heat Pumps

    Hi Peter the unit I mentioned above was a Climatemaster floor mounted unit which probably had too much water flow rate to start with. But in the last week I had been working on a Diamond unit where the outdoor unit fans have been disabled due to tripping on HP in heat mode. The unit was sized for mainly cooling, full fresh air Sydney conditions. The primary heat is EDHs and it uses Copland scrolls which I am told can handle a little flood back. This would be (in my opinion) caused by a much larger outdoor coil than the indoor coil. I think with this system the fans could/should run at a reduced speed on the outdoor unit during heat mode. This would limit flood back and excessive high pressures.

  6. #6
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    Re: Extra Charge - Heat Pumps

    Hi Peter_1,

    Tesla is correct! The problem is not so much in water cooled system as condenser is not that big. But in Air to Air systems, condenser (cooling mode) needs to be bigger, when this becomes evap in heating mode the charge requirement is much less as compare to what has been used in cooling mode.

    I need to know what others do to compensate this extra charge??

  7. #7
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    Re: Extra Charge - Heat Pumps

    Then a liquid receiver is the solution
    It's better to keep your mouth shut and give the impression that you're stupid than to open it and remove all doubt.

  8. #8
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    Re: Extra Charge - Heat Pumps

    The problem with receivers is a longer dip tube only on one side. It will work in any one mode but in reverse cycle, only vapors will go to evap.

    Any other ideas!!

  9. #9
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    Re: Extra Charge - Heat Pumps

    A receiver with 2 dip tubes of course like this one
    Attached Images Attached Images
    It's better to keep your mouth shut and give the impression that you're stupid than to open it and remove all doubt.

  10. #10
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    Re: Extra Charge - Heat Pumps

    General view, 2 'normal' OEM receivers and one for the reevrsible heatpump
    Attached Images Attached Images
    It's better to keep your mouth shut and give the impression that you're stupid than to open it and remove all doubt.

  11. #11
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    Re: Extra Charge - Heat Pumps

    Do U think an Accumulator will work??

  12. #12
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    Re: Extra Charge - Heat Pumps

    Quote Originally Posted by Peter_1 View Post
    General view, 2 'normal' OEM receivers and one for the reevrsible heatpump
    nice but shouldnt a reciever have a fusible plug/safety blow off and be stamped with volume and max pressure.otherwise 2.4mtr of pipe to weigh in.

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