The Carrier SC2 Gas Furnace is a high-efficiency residential heating system designed for reliable performance and energy savings. This model features variable-speed blower technology, electronic ignition, multiple heat stages, and advanced diagnostic capabilities. Suitable for single-family homes and multi-zone applications, the SC2 operates on natural gas with AFUE ratings up to 98.5%. Below are key sections covering safety, installation, operation, maintenance, and troubleshooting.
Key components: Variable-speed ECM blower motor, hot surface ignitor, stainless steel heat exchanger, integrated control board, pressure switches, flame sensor, and diagnostic LED.
| Feature | Description |
|---|---|
| Variable-speed blower | Provides consistent airflow and quiet operation |
| Electronic ignition | Hot surface ignitor for reliable startup |
| Multi-stage heating | Two-stage gas valve for improved comfort |
| Diagnostic LED | Flashing codes for troubleshooting |
| Pressure switches | Ensures proper venting operation |
| Flame sensor | Monitors burner operation |
| Gas valve | Precise gas flow control |
| Limit switches | Prevents overheating |
| Blower door switch | Safety interlock |
| Condensate drain | Removes combustion byproducts |
Professional installation required. Verify local codes and obtain permits.
WARNING! Gas furnaces produce carbon monoxide; proper venting is critical. Only qualified technicians should install.
Professional startup procedure required for warranty validation.
CAUTION! Never bypass safety controls. Test carbon monoxide detectors after installation.
Integrated furnace control board manages all operations. Thermostat compatibility: Conventional and programmable thermostats.
Control Board LED: Steady on = normal operation. Flashing codes indicate specific faults.
Operation sequence: Thermostat calls for heat → inducer motor starts → pressure switch proves draft → hot surface ignitor heats → gas valve opens → flame sensor confirms ignition → blower starts after heat exchanger warms.
Direct vent or conventional venting options available.
Tip: Always install carbon monoxide detectors when installing gas appliances.
Annual professional maintenance recommended for optimal performance.
WARNING! Turn off gas and electrical power before performing any maintenance.
Multiple safety systems protect against hazardous conditions. Flame rollout switches: Detect improper burner flames. Limit switches: Prevent overheating. Pressure switches: Ensure proper venting. Blower door switch: Disables operation when panel removed.
Keep area around furnace clean and unobstructed. Change filters regularly. Schedule annual professional inspection.
CAUTION! Never store flammable materials near furnace. Keep combustion air vents clear.
UL certified. ANSI Z21.47/CSA 2.3 compliant. Meets U.S. Department of Energy efficiency standards. Manufactured to comply with EPA regulations. For support, contact Carrier at 1-800-CARRIER or visit www.carrier.com. Installation must comply with National Fuel Gas Code NFPA 54 and local codes.
| Symptom | Possible Cause | Corrective Action |
|---|---|---|
| Furnace won't start | Power, thermostat, door switch | Check circuit breaker; verify thermostat setting; ensure door properly closed. |
| No heat | Gas supply, ignitor, flame sensor | Verify gas valve on; check for flashing LED codes; clean flame sensor. |
| Short cycling | Dirty filter, limit switch | Replace air filter; check for restricted airflow; verify proper temperature rise. |
| Blower won't stop | Thermostat, control board | Check thermostat fan setting; inspect control board operation. |
| Unusual noises | Blower, inducer, ductwork | Inspect blower wheel; check inducer motor; examine duct connections. |
| Error codes flashing | Various system faults | Count LED flashes and refer to service manual for specific code meaning. |
Reset: Power cycle furnace by turning off power for 30 seconds then restoring.
Service: 1-800-CARRIER; www.carrier.com