HVACopediaCarrier · Furnace · Cooling
Furnace blower with outdoor A/C: cooling and continuous fan
What happens, in order
- Thermostat closes R-Y and R-G
- R-Y starts the outdoor unit; R-G with Y starts the furnace blower on cool speed; air cleaner terminal is powered
- Thermostat satisfied outdoor unit stops and the blower keeps running on cool speed for 90 s
- Cutting jumper J2 shortens the cooling off-delay to 5 s
- Continuous fan (R-G only) blower runs on fan speed; during a heating call it stops through igniter warm-up (17 s), ignition and the 25 s blower-on delay, then returns on heat speed
- When R-G opens in continuous fan the blower runs on 5 s more if nothing else needs it
Timings and thresholds
| Item | Value |
|---|---|
| Cooling blower-off delay | 90 s (5 s with J2 cut) |
| Blower-off after G opens | 5 s |
Applies to: Carrier 58SB0A / 58SB1A 80% single-stage gas furnace
Models
58SB0A58SB1A
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Source: Carrier 58SB0A/58SB1A installation manual, Sequence of Operation. 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.