HVACopediaCarrier · Furnace
22.1 False flame
What the control is telling you
The control sees flame when there should be none. It locks out of gas heating and keeps the inducer running until flame is no longer sensed.
Applies to: Carrier 59SC6A
Likely causes
- Gas valve leaking through or not closing
- Flame sensor shorted or wire grounded
- Moisture or contamination at the sensor
- Control fault
Test and repair steps
- Warning: If flame is visible with no call for heat, shut off the manual gas valve immediately.
- Look through the burner area with no heat call to see if a real flame is present.
- If a real flame exists, the gas valve is leaking through: replace the gas valve.
- If no flame, check the flame sensor and its lead for a short to ground or cracked insulator.
- Check for condensate/moisture reaching the sensor area.
- If wiring and sensor are fine, replace the control and program it with the rating-plate Model Program Number.
Settings for these units
Filter sizes by casing width and filter cabinet · 59SC6A
| Location | Size | Side return filter | Bottom return filter | Type |
|---|---|---|---|---|
| Furnace casing | 14-3/16 in. wide | 16 x 25 x 3/4 in. | 14 x 25 x 3/4 in. | Washable |
| Furnace casing | 17-1/2 in. wide | (1) 16 x 25 x 3/4 in. | (1) 16 x 25 x 3/4 in. | Washable |
| Furnace casing | 21 in. wide | (1) 16 x 25 x 3/4 in. | (1) 20 x 25 x 3/4 in. | Washable |
| Furnace casing | 24-1/2 in. wide | (1) 16 x 25 x 3/4 in. | (1) 24 x 25 x 3/4 in. | Washable |
| Filter cabinet | 16 in. high | (1) 16 x 25 x 3/4 in. or (1) 16 x 25 x 4-5/16 in. | - | Washable or media |
| Filter cabinet | 20 in. high | (1) 20 x 25 x 3/4 in. or (1) 20 x 25 x 4-5/16 in. | - | Washable or media |
| Filter cabinet | 24 in. high | (1) 24 x 25 x 3/4 in. or (1) 24 x 25 x 4-5/16 in. | - | Washable or media |
Side-return filters can differ in size - measure the existing filter.
Every return-air inlet needs a filter.
Minimum clearances to combustibles · 59SC6A
| Position | Minimum clearance |
|---|---|
| Rear | 0 |
| Front (combustion air openings in furnace and in structure) | 1 in. (25 mm) |
| Required for service | 24 in. (610 mm) (see note) |
| All sides of supply plenum | 1 in. (25 mm) (see note) |
| Sides | 0 |
| Vent | 0 |
| Top of furnace | 1 in. (25 mm) |
Service and supply-plenum values are marked 'consult local building codes'.
Keep 1 in. (25 mm) from combustibles to supply ductwork for 36 in. (914 mm) horizontally from the furnace.
Models that show this code
11 models in 59SC6A
Other codes on the same units
- 14.1 Ignition lockout after 4 tries
- 14.2 Lockout - flame lost 3 times after 70 s of heating
- 14.3 Lockout - 7 flame-loss events in one heat call
- 21.1 24 VAC on gas valve when it should be off
- 23.1 Main pressure switch stuck closed
- 23.2 Secondary pressure switch stuck closed
- 24.1 Fuse fault (24 V)
- 25.1 No program in control
Save it for the next call
Star this code in the HVACopedia app and keep the whole library on your phone for jobs with no signal.
Source: Carrier 59SC6A Installation, Start-up, Operating and Service Instructions, Fig. 60 Service Label p.54; Sequence of Operation p.69. Summarized in our own words; check the original manual for your model.
Homeowner looking at this code? See what it means for you and when to call a technician.
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.