HVACopediaTrane · Air handler · Cooling
Modular blower cooling call (single and two-stage)
What happens, in order
- Thermostat closes R-Y1-G, sending 24 V to Y1 and G on the blower control; expect 24 V between Y1 and B/C and between G and B/C
- 24 V goes to the outdoor unit through the thermostat wiring and starts the first-stage compressor
- Indoor blower ramps to first-stage cooling airflow; the display alternates CL1 and ARF (calculated airflow, shown value times 10)
- The factory Y1-O jumper must stay in place for the CL1 readout; with it removed the display shows HP1
- Second stage R-Y2 closes, 24 V reaches Y2, the outdoor unit goes to second stage and the blower ramps to second-stage airflow (display CL2)
- Satisfied contacts open, the outdoor unit stops and the blower stops, unless a blower off delay is enabled in the menu (display returns to IDL)
- First-stage airflow is set from the ODU menu: 80 percent for 2-stage with one compressor, 50 percent for 2 compressors
Timings and thresholds
| Item | Value |
|---|---|
| Airflow display | value x 10 (080 = 800 cfm) |
| Calculated airflow settle time | about 1 to 2 min |
| First-stage airflow, 1 compressor | 80 percent |
| First-stage airflow, 2 compressors | 50 percent |
Codes you may see during this
CL1, CL2, IDL, ARF; blower faults e01, e6.1, e6.2, e12 to e18 on the display
Applies to: P0V0 modular blowers on air conditioning
Models
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Source: Trane P0V0 modular blower installation 18-GE20D1-1E-EN (Nov 2021), Sequence of Operation pp.30-33. Written in our own words; timings can differ by model and software version, so check the manual for your exact unit.
For licensed technicians. Gas, electrical and refrigerant work must be done by a qualified, licensed person. Shut off power and gas before servicing, never bypass a safety control, and follow the manufacturer’s manual for the exact model; it and local codes always take priority. HVACopedia is not affiliated with any manufacturer; brand and model names only identify the equipment.