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Preliminary Procedure: "Lo-Auto"

As button is pushed, blower voltage should reduce. Rotate tester mode knob to "HEAT", the following should take place in order listed:

  1. Blower speed drops one step and air door goes from 20% to 100% outside air. There should be no change in discharge air temperature.
  2. Blower speed should decrease three further steps with an increase in discharge air temperature each time blower speed is automatically reduced one step.
  3. After fourth decrease in blower speed, system should automatically shift from A/C mode to Heat mode. As this occurs, blower speed should increase one step and there should be an additional rise in discharge air temperature. Move thermometer to heat outlet duct.
  4. In two or three minutes, blower speed should increase three more steps with an increase in discharge air temperature at each step. Final discharge air temperature should be approximately 140°F (maximum).
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