Service tech disabled/jumped my loop pressure switches. Bad?

Discussion in 'General Discussions' started by madnah, May 15, 2020.

  1. madnah

    madnah New Member

    Hi all-

    Late last year, I had a $500 electric bill that I discovered was caused by my system running on backup heat for weeks. The compressor wouldn't start due to a high pressure fault. A technician came out and got it working again, though at the time, I didn't understand exactly how. He said he disabled something that was "really only needed for commercial installs".

    Fast forward to today, I'm looking at the board to verify the wiring so I can install a smart thermostat. I see that he took the loop pressure switches out of the circuit and shorted the connections. And I also see the label on the switches warning explicitly to NOT do this.

    Is this bad, and do I need to get it fixed? Thanks in advance for any help.


    [​IMG]
     
  2. Eric Kurtz

    Eric Kurtz Member

    My first thought is, "Not good". If those switches are the high pressure safeties for the refrigerant loop, and they sure look like it, they should not be disconnected. A temporary fix to get heat or AC going if you don't have the proper parts is probably ok. But not for months.
     
  3. madnah

    madnah New Member

    Pardon my ignorance, but when you say "refrigerant loop", that's not the ground/water loop right? These switches are on the ground loop.
     
  4. Eric Kurtz

    Eric Kurtz Member

    Are you sure? They are exactly like the high pressure switches in refrigerant loops. They are there to protect the compressor and other components if something would fail and cause the pressure to spike to dangerous levels. I'm not very familiar with the various protections that might be on the ground loop, but see no reason for anything like that in the ground loop unless maybe as a low pressure protection on a pressurized system. Are they located on the coaxial heat exchanger (it is hooked to the ground loop source "in" and "out" ports)?
     
  5. Eric Kurtz

    Eric Kurtz Member

    More pictures might help.
     
  6. madnah

    madnah New Member

    Here is a picture from a wider angle, disabled switches circled again:

    [​IMG]


    Here are (what I think are) the pressure switches on the refrigerant loop. These weren't touched:

    [​IMG]



    EDIT: Found this interesting blurb in the installation manual:

    CAUTION! Many units are installed with a factory or field
    supplied manual or electric shut-off valve. DAMAGE WILL
    OCCUR if shut-off valve is closed during unit operation. A
    high pressure switch must be installed on the heat pump side
    of any field provided shut-off valves and connected to the
    heat pump controls in series with the built-in refrigerant circuit
    high pressure switch to disable compressor operation if water
    pressure exceeds pressure switch setting. The field installed
    high pressure switch shall have a cut-out pressure of 300
    psig and a cut-in pressure of 250 psig. This pressure switch
    can be ordered from ClimateMaster with a 1/4” internal fl are
    connection as part number 39B0005N02.
     
    Last edited: May 15, 2020
  7. Eric Kurtz

    Eric Kurtz Member

    That makes sense. According to that info then, the tech is probably right. But someone else will have to explain why you would need a 300 psi cutout on the ground loop.
     
  8. madnah

    madnah New Member

    Thank you for the input. I am going to call ClimateMaster tomorrow to see if they'll give me any info, and then I will report back.
     
  9. madnah

    madnah New Member

    Following up. I was pleasantly surprised how easy it was to reach someone in technical support and she didn't have any qualms with helping out a home owner (even though one their menu options directed me to a distributor). She confirmed that in a single-family residential install with a "normal" ground loop of ~50 PSI, these switches are in fact unnecessary. They are indeed primarily for commercial installs where the loop is much longer/higher, and would require higher operating pressure. No harm can come to any components in my residential system, so the contractor was correct. And now my mind is very much at ease.
     
    waterpirate likes this.

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