Minnesota Climatemaster T27 fault code 2

Discussion in 'Maintenance and Troubleshooting' started by steveeri39, Jan 12, 2021.

  1. steveeri39

    steveeri39 New Member

    ClimateMaster T27, intermittent HP fault, code 2. Will run a few days typically till hard
    fault, else will slow cycle the status light and start compressor on retry.

    Schematic shows the red wires in series to cause HP fault, HP switch/HPWS in and out.

    The pump is Geopulse, not pressurized.
    4 degrees temp drop of incoming water, (5 wells - loop), glycol.

    Failed last night and has been running fine since I cycled the breaker.
    I am considering bypassing the HPWS switches to isolate, maybe one is bad. If it still
    fails, wire around the HP switch.
    We used to have support in this area for geothermal, but no more, may have to go as far as
    Steve Grand Rapids
  2. steveeri39

    steveeri39 New Member

    Another question, what causes a real HP fault? Does heat build up in the compressor freon, that then causes the pressure to exceed spec? I have the fan at a low speed, maybe increasing the speed would allow more heat to escape and reduce pressure.
    I have a gauge for a car freon check, will see if it works, else may purchase one for the furnace.

  3. geoxne

    geoxne Active Member Forum Leader

    High refrigerant pressure while heating is most commonly caused by low or no air flow. Check your airfilter, make sure outlets and returns are not obstructed. If you reduced your fan speed, turn it back up. Climatemaster publishes minimum fan speeds required in their documentation for specific units

    Do not bypass the high pressure safety switch.
  4. steveeri39

    steveeri39 New Member

    Air filter is new, furnace has been installed ~7 years. Slowed airflow 2 years ago, problem has been getting worse in last week or so, started ~6 weeks ago.

    I increased air flow a lot and if still failed.

    An odd behavior was confirmed, at least 4 times I noticed the compressor had stopped (slow blinking status LED), so I check the error code, always 2, short test pins. Within a few seconds the compressor turns on,
    5 minutes have not elapsed. Expected behavior?

    Next step is to bypass the HW pressure switches.

    Get a pressure gauge for the furnace.
    New CXM board

    thanks for the help

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