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  1. #1
    Join Date
    Nov 2010
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    14
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    Rheem High Pressure Cut-out

    In August I installed my second Rheem Heat Pump for a customer's rental property. It was installed in the attic for the upstairs. When I first checked it out at install everything worked fine in AC. At the time I installed the unit, the tenant had his BR downstairs and only went upstairs to take a shower so he left it off. This unit doesnt have 10 hours of total run time on it. Tenant lives by himself and had his bedroom in the down stairs portion of the house and just moved his BR upstairs on Sunday evening. That is when he turned it on for heat and it wouldnt come on.

    I went over to the property to check it out and the board had LED1 flashing and LED2 was off. The board has a fault table on it and according to the table it tripped out for High Pressure Lock Out. The high pressure lock out cut the power on the brown common to the contactor. The yellow to the contactor from the stat had power, as did the Blue Reversing valve.


    I unplugged low voltage power to the board and plugged it back in after a few minutes and everything started working fine. The two LEDs now show a normal status and the unit is working as expected. I told him to give me a call if any problems return.

    Have any of you Ruud/Rheem guys seen this on new units? It is a 2 ton unit if it matters. The first Rheem 3 ton heat pump I installed in July went flawless with no issues. Any tips or advice on what I should check for if this issue returns?

    Thanks for any help

  2. #2
    Join Date
    Jul 2019
    Location
    Oklahoma home its in the name
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    710
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    Checklist:
    Air filter
    Are many dampers closed?
    Blower wheel
    Static pressure compare to fan chart and blower setting.
    Do the Model# Serial# of the indoor unit match the acceptable matches in the outdoor unit literature?

    Sent in a state of increasing entropy using Tapatalk

  3. #3
    Join Date
    Jul 2019
    Location
    Oklahoma home its in the name
    Posts
    710
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    That last one actually happened to us. Trane gave us the ac only coil for a heatpump. Took us a bit to figure that one out.

    Sent in a state of increasing entropy using Tapatalk

  4. #4
    Join Date
    Nov 2010
    Posts
    14
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    Thread Starter
    Quote Originally Posted by R600a View Post
    Checklist:
    Air filter
    Are many dampers closed?
    Blower wheel
    Static pressure compare to fan chart and blower setting.
    Do the Model# Serial# of the indoor unit match the acceptable matches in the outdoor unit literature?

    Sent in a state of increasing entropy using Tapatalk
    Thanks R600a...

    Yes the model and serial number match. They were purchased from the supply house at the same time along with a honeywell media filter and housing. The media filter is really clean as he hasnt been using it.

    I guess I got tunnel vision and was focused on equipment and sensors instead of slowing down and thinking about what is most likely happening.

    The tenant is very frugal. I know he has at least two vents shut off for the two bedrooms he isnt using. He also keeps all the doors closed upstairs, but the return is in the hallway. So the bedrooms are probably over pressurizing with the doors closed and the return getting air from downstairs instead of getting it from the bedrooms probably results in not enough air going across the coil, thus raising the pressure.

    If it does trip out again, Ill tell him to leave the doors open and see what is happens.

    Thanks again

  5. #5
    Join Date
    Mar 2018
    Location
    Kansas Flatlands
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    382
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    What model #? Did you add charge? Sit on the system and watch the guages and check subcooling to the chart listed in the unit. Up flow or downflow or horizontal left/right have different charts on Rheem heatpumps and can be drastically different in some cases. Most all hp trips I find are air flow related (dirty filter etc.) or too much refrigerant added in the cool mode. What was the odt when it tripped? 6 oz. too much on a 2 ton system is a lot when you turn it to heating mode. You must commission a new system.

    Anybody can make a heatpump cool, heating is critical of everything. Good luck my friend

  6. Likes R600a liked this post
  7. #6
    Join Date
    Jul 2019
    Location
    Oklahoma home its in the name
    Posts
    710
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    I am happy to help. Sometimes we get stuck on what we think is wrong.

    I tell my customers to only use the dampers for balancing not to try and save energy.

    Definitely check airflow if you didnt already.
    It is not too uncommon for modern equipment to not be capable of pushing the proper airflow with any more than a coil and cheap filter.
    Quote Originally Posted by komobu View Post
    Thanks R600a...

    Yes the model and serial number match. They were purchased from the supply house at the same time along with a honeywell media filter and housing. The media filter is really clean as he hasnt been using it.

    I guess I got tunnel vision and was focused on equipment and sensors instead of slowing down and thinking about what is most likely happening.

    The tenant is very frugal. I know he has at least two vents shut off for the two bedrooms he isnt using. He also keeps all the doors closed upstairs, but the return is in the hallway. So the bedrooms are probably over pressurizing with the doors closed and the return getting air from downstairs instead of getting it from the bedrooms probably results in not enough air going across the coil, thus raising the pressure.

    If it does trip out again, Ill tell him to leave the doors open and see what is happens.

    Thanks again
    Sent in a state of increasing entropy using Tapatalk

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