Carrier · Comfort 96 (59SC6A) · Model
Carrier Comfort 96 59SC6A 100M21–20
The 59SC6A 100M21–20 is the 100,000 BTU/h, 21-inch-wide Comfort 96: 97,000 BTU/h output on a single gas rate, 96.3% AFUE upflow, with a 1 HP multi-speed ECM blower. It serves larger, older or leakier houses whose heat-loss calculation lands above the 080 size.
Rating plate
- Model
- 59SC6A 100M21–20
- Input
- undefined – 100,000 BTU/h
- Output
- undefined – 97,000 BTU/h
- AFUE
- 96.3% upflow · 95% down/horiz
- Burner
- Single-stage
- Blower
- ECM, constant torque (variable-speed)
- Fuel
- Natural gas / Propane
- Cabinet
- 35 × 21 × 29.5 in
- Canada
- Available in Canada
A single-stage furnace at 100,000 BTU/h input is a full-fire machine: every heating cycle burns at maximum until the thermostat is satisfied. For houses that genuinely calculate to this capacity, it is the least expensive honest answer in Carrier's line; for houses that do not, it is a short-cycling mistake, and Carrier's product data carries the usual warning that excessive oversizing can shorten furnace and vent life.
The 21-inch cabinet with five burners and a 1 HP MCT ECM blower moves 1,730 CFM in heating and up to 2,145 CFM for cooling. The 100M21–22 sibling in the same cabinet adds an extended airflow profile (up to 2,240 CFM) at the same certified 96.3% upflow.
Among Lower Mainland homes this size appears most in pre-1960 houses with original envelopes and little insulation, and in retrofit jobs where the calculation confirms the old furnace was not oversized. When a house has been upgraded since its old furnace was installed, the number usually comes back lower.
Specifications
From Carrier's published product data. Input and output are listed separately; AFUE depends on installation position.
| Specification | Value | Note |
|---|---|---|
| Input | ||
| Input | 100,000 BTU/h | |
| Output | ||
| Output capacity | 97,000 BTU/h | Carrier product data; DOE test procedure, position dependent. |
| Efficiency | ||
| AFUE, upflow / horizontal | 96.3 % | |
| AFUE, downflow | 95 % | |
| Airflow | ||
| Certified temperature rise range | 40 – 70 °F (22 – 39 °C) | |
| Airflow, heating @ rated ESP | 1,730 CFM | |
| Cooling airflow range | 375 – 2145 CFM | |
| Blower motor | Multi 18-speed, constant-torque (MCT) ECM | Not a communicating constant-airflow motor; speeds are installer-selectable. |
| Physical | ||
| Cabinet width | 21 in | 533 mm |
| Shipping weight | 167 lb | 76 kg |
| Cabinet height | 35 in | 889 mm |
| Cabinet depth | 29.5 in | 750 mm |
| Installation positions | Upflow, downflow, horizontal left, horizontal right | |
| Venting | ||
| Venting | Direct vent (2-pipe), single-pipe, or ventilated combustion air on sizes above 26,000 BTU/h; the 26,000 BTU/h size uses 2-pipe venting with outside combustion air and is not classed as direct-vent | |
| Electrical | ||
| Blower motor | 1 HP | |
| Maximum unit amps | 12.6 A | |
| Maximum fuse / breaker | 15 A | |
| Electrical supply | 115 V, 60 Hz, 1 phase (104 – 127 V) | |
| Controls | ||
| Burner staging | Single-stage (full fire on every call) | |
| Other | ||
| Burners | 5 | |
| Inducer | Single-speed | |
| Fuel | Natural gas; propane with gas conversion accessory kit | |
Variants
Sizes that share this model page. A variant gets its own page only when it has substantial independent value.
| Size | Input high | Input low | Output high | Output low | AFUE upflow | AFUE down/horiz | Width (in) | Ship wt (lb) | Cooling CFM | Motor HP |
|---|---|---|---|---|---|---|---|---|---|---|
| 100M21–20 | 100,000 | — | 97,000 | — | 96.3 | 95 | 21 | 167 | 375 – 2145 | 1 |
| 100M21–22 | 100,000 | — | 97,000 | — | 96.3 | 95 | 21 | 167 | 450 – 2240 | 1 |
Filters, serial numbers and service parts
Filter
- Field-supplied filter; certified watt data uses Carrier media filter 325531-40
Components this family's service documentation covers
- Hot-surface ignitor
- Flame sensor
- Pressure switches
- Inducer motor
- Condensate trap and drain components
- ECM blower motor
- Control board
Service-parts list source: Components documented for service in 59SC6A-01SI REV D.
Fault codes this model can show
Best for
- Larger and older detached homes with higher verified design heat loss
- Houses with a 4- to 5-ton air conditioner or heat pump on shared ductwork
- Replacements where the heat-loss calculation genuinely supports the capacity
Compatible controls
- Standard 24 V thermostat terminals: G, C, W, Y, R
- On-board 3-digit status display with NFC setup via the Carrier service technician app
- EAC-1 (115 VAC), HUM (24 VAC) and 1-stage AC accessory connections
System integrations
- Air conditioner or heat pump (dual-fuel / Hybrid Heat) with a compatible thermostat
- Twinning of two furnaces with the accessory kit (selected sizes only)
- Manufactured (mobile) home applications with the MH accessory kit (selected sizes)
- Field-supplied filter or optional media filter cabinet
Manuals, codes and service
Documents
- 59SC6A Product Data — Comfort 96, Single-Stage, Multi 18-Speed ECM (59SC6A-01PD REV B)
- 59SC6A Installation, Start-up, Operating and Service and Maintenance Instructions (59SC6A-01SI REV D)
Fault codes that apply
- Code 23: pressure switch stuck closed
- Code 24: fuse fault
- Code 25: control program and configuration faults
- Code 27: super plug or control program fault
- Code 31: secondary pressure switch open or lockout
- Code 32: open main pressure switch (LPS)
- Code 33: a switch has opened in the main limit circuit
- Code 34: ignition fault or flame loss
- Code 45: control failure
- Code 46: momentary loss of power
- Code 10: rapid flash - L1 polarity fault
- Code 12: W on at power up
- Code 13: limit lockout or ignition lockout
- Code 14: flame-loss lockouts during a heat request
- Code 21: 24 VAC sensed on the gas valve when it shouldn't be
- Code 22: false flame
BC Wide service
This catalogue page is reference information for anywhere in Canada. On-site service for this model is available across Greater Vancouver from BC Wide's Burnaby base — see furnace service in Burnaby and all service areas.
Questions people ask
When does a house actually need 100,000 BTU/h in the Lower Mainland?
Only when the heat-loss calculation says so. Many larger houses calculate below this after insulation and window upgrades. Ask for the calculation before accepting a size this big.
What is the difference between the 100M21–20 and the 100M21–22?
Identical input, output and certified AFUE in the same cabinet. The 100M21–22 has the extended blower airflow profile (up to 2,240 CFM for cooling versus 2,145 CFM).
Considering the 59SC6A 100M21–20?
Get a published ballpark range for a supply-and-install, then a consultation to confirm sizing from a heat-loss assessment. Equipment-only pricing is not offered on this site.