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Unit Sequence of Operation
On 24 VAC power-up or outdoor reset, the outdoor control shall perform the following tasks:
Start the anti-short cycle 3-minute delay in the outdoor control.
1.
Check status of the temperature sensor and pressure devices.
2.
If the outdoor control does not detect any error codes, outdoor control sends 24 volts out on the
3.
CNTCTR terminals to pull in the contactor coil. (Note - These checks take about 60 seconds.)
The contactor contacts pull IN and main power is applied to the compressor inverter.
4.
No
31-5000750 Rev. 1
From idle mode
Room thermostat provides a Y1 or Y2 demand to
the main control.
Yes
All switches closed
and sensors in
operating range.
Yes
Outdoor Control
1. Sends a demand to the compressor
inverter to start and run the
compressor up to the requested
pumping capacity (Frequency in
hertz).
2. Output signal is provided on PWM
and COM terminals to start and run the
ECM outdoor fan at the demand RPM.
Figure 25. Volt Power-Up or Outdoor Reset
Check for status or
fault codes in the
outdoor control.
No
(NOTE - Refer to low
pressure and high
pressure switch flow
charts for sequence
of operation.
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