A ‘No Cool’ Situation
Author’s Note: This month’s troubleshooting problem, a very specific one that might take some research if you’re not familiar with the process of combustion analysis, is a result of a request from a reader. If you have suggestions for a problem, please, write or email. You can reach Jim directly at Technical Training Associates, HC 70 Box 3172, Sahuarita, AZ 85629 or at tta@dakotacom.net.) tta@dakotacom.net.
By Jim Johnson
Contributing Editor
In this month’s troubleshooting situation an elderly customer has called to say that their “air conditioner isn’t working at all.” When asked by the dispatcher if they heard any sound coming from their system, their answer was “no.”
Arriving at the customer’s home, however, you discover that something is happening. You determine that this unit is a heat pump. After checking inside to make sure that the thermostat is set properly to the cooling mode, your initial check on this rooftop package unit proves the outdoor fan motor is running. You also note that the compressor is running and that the suction line is frosting and sweating. Removing the access cover for the indoor fan motor, you find that the squirrel cage is not moving, but turns freely when you spin it manually.
Checking the wiring diagram (Figure One), your voltmeter, when placed at the L2 connection on the ID, and at the first 2R connection on the relay wired in series with the motor on the L1 side of the line, reads 240-volts—your next voltmeter-check at the other side of the relay shows 0 volts. Moving to the 2R coil, your voltage-check there shows 24-volts.
Your troubleshooting question: What is it that is preventing the ID from operating?
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Troubleshooting
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All correct answers will be entered into two drawings. The monthly prize drawing will be a CD copy of Jim's new E-Book 20 Troubleshooting Problems, and also an EDHL1 Electronic Handle and ACH Current Clamp Head.
The quarterly drawing will be for a digital meter combo kit courtesy of Fluke Corporation.
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