Ohio How can you tell it is running in stage 2?

Discussion in 'Maintenance and Troubleshooting' started by eaerhard, Jan 13, 2016.

  1. mrrxtech

    mrrxtech Member

    How do you know when the 2nd stage is being called for?

    The Carrier Unit Fan ECM Control Card has small chip style yellow LEDs at each input line at the connector starting with the G (Fan) line from the thermostat, followed by the Y1 (Compressor Start) input and then the Y2 input, as well as other input signals. I assume your Climatemaster uses the same ECM card since the cabinets look similar and are probably made in the same factory.

    If you watch the card as the unit starts up the Fan LED will energize, then the Y1 LED, followed by the Y2 LED when you raise the thermostat setting to 2 or 3 degrees above the current house temperature, in the heating mode.

    This is how I can tell if the 2nd stage coil is being called for. The sound of the compressor load increase will follow if the Compressor is working properly.
    Not being hooked up would qualify as "not working properly".
  2. eaerhard

    eaerhard Member

    I can tell stage 2 is being called for on the t-stat and can hear the fan speed ramp up. Before, I would see my LAT drop about 10 degrees but now that the power for stage 2 is connected to the compressor, I get LAT that actually increases from stage 1 by about 1-2 degrees even though the air speed is increased by 400 CFM. My board still looks and acts the same because everything was connected to it properly, it just wasn't connected to the compressor.... I do not hear a difference in the compressor because the fan ramps up and drowns it out.
  3. mrrxtech

    mrrxtech Member

    If you have the Unit open you can tell what is being called for by the thermostat using the above. Hopefully you won't have to Trouble Shoot your Unit again for a few years or more.
  4. eaerhard

    eaerhard Member

    Thanks mrrxtech!

    I thought for the longest time that the system was not performing as it should and have had a few eyes on it including other geo pros and the installer and nothing looked out of place. All was being called for correctly and the board was even showing correct operation, it just wasn't producing the heat in stage 2 because it didn't have the second power connection connected for stage 2 compressor. It was connected to the board so the board looked correct, it just wasn't powering anything! Basically the board was sending all signals as it was supposed to but the compressor wasn't energizing stage 2 operation with the stage 2 power disconnected at the compressor. I am shocked that it didn't send any error codes to the indicator light on the board or to the thermostat! Honestly I though I made a huge mistake in going Geo because of how it operated when it got cold enough for stage 2, but now that we have had to run in stage 2 since fixing it, it is great!
  5. mrrxtech

    mrrxtech Member

    The Carrier 2 stage 3 ton has the compressor exposed in the lower cabinet. I noticed you said you had to remove a panel.
    I guess that's why no one else saw the 2nd stage power plugs disconnected.
    That must have been a factory error since the 3 Ton Carrier 2nd stage plug for the compressor was installed when it arrived from the factory.

    I noticed that you found the problem yourself.
    It pays to get to know your geothermal. You saved yourself some repair bills and are saving on electric use by not having an undersized Unit.

    If you lose half of your 220 vac power to the house due to a tree limb or transformer problem, you will probably burn up the 24vac transformer that powers up the thermostat, operates the compressor contactor and powers up the cards. That happened early in the life of the Carrier 3 Ton.
    Replacement 24 vac transformers with the breaker/reset button on the Secondary side (shown on schematic but not on the transformer), are relatively cheap on ebay. It's an easy fix.

    I hope you have many years of service before your first fault.

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