HVACopediaCarrier · Furnace
12 Blower on after power-up (normal)
What the control is telling you
Normal: if power is restored during a heat call, or R-W/W1 opens during the blower on-delay, the blower runs 90 seconds and the LED flashes 12 until it finishes.
Applies to: 59TP6A two-stage variable-speed ECM multipoise condensing gas furnace, all sizes (040-10 to 120-22)
Likely causes
- Power interruption (115 V or 24 V) during a call for heat
- Heat call ended during blower on-delay
Test and repair steps
- Wait out the 90-second blower-only period; the control starts it 2 seconds after power returns if heat is still called.
- Confirm the LED goes to continuous ON afterward and the furnace responds normally to the thermostat.
- If it repeats often, look for intermittent power: loose supply connections, door switch, or breaker.
- Note a power interruption also erases the adaptive-heat history, so the next cycle may run low heat up to 16 minutes before high heat.
Settings for these units
Filter sizes by casing width and filter cabinet · 59TP6A
| 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 | 16 x 25 x 3/4 in. | 16 x 25 x 3/4 in. | Washable |
| Furnace casing | 21 in. wide | 16 x 25 x 3/4 in. | 20 x 25 x 3/4 in. | Washable |
| Furnace casing | 24-1/2 in. wide | 16 x 25 x 3/4 in. | 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 |
No internal filter rack in this furnace - an external filter is required.
Side-return filters can differ in size - measure the existing filter.
Minimum clearances to combustibles · 59TP6A
| Position | Clearance |
|---|---|
| Rear | 0 in. (0 mm) |
| Front (combustion air openings) | 1 in. (25 mm) |
| Front, required for service | 24 in. (610 mm) - check local code |
| All sides of supply plenum | 1 in. (25 mm) - check local code |
| Sides | 0 in. (0 mm) |
| Vent | 0 in. (0 mm) |
| Top of furnace | 1 in. (25 mm) |
Keep 1 in. from combustibles to supply duct for 36 in. horizontally from the furnace.
Do not set on carpet or combustible tile; downflow on combustible floor needs the accessory floor base unless on a matching coil casing.
- Filter sizes by casing width · 58SB0A/58SB1A
Models that show this code
22 models in 59TP6A, 58SB0A/58SB1A
Other codes on the same units
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 59TP6A Installation, Start-up, Operating and Service Instructions, Fig. 66 Troubleshooting Guide, p.88; Sequence of Operation, p.85. 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.