criterion ii gas furnace manual upflow

The Criterion II Gas Furnace Upflow is a high-efficiency residential heating system designed for vertical airflow installation. This natural gas furnace features multi-speed blower operation, electronic ignition, built-in draft inducer, thermal efficiency ratings up to 96% AFUE, safety shut-off controls, diagnostic LED indicators, and compatibility with standard thermostat systems. Suitable for installation in closets, utility rooms, or dedicated furnace spaces. Below are essential sections covering safety, specifications, installation, operation, maintenance, and troubleshooting.

Features at a Glance

Key components: Upflow configuration, gas valve, heat exchanger, blower assembly, draft inducer motor, control board, pressure switches, flame sensor, and diagnostic LED.

Installation Requirements

Proper installation is critical for safe and efficient operation. Follow all local codes and manufacturer guidelines.

1. Location: Install in well-ventilated area with adequate combustion air and service clearance.
2. Gas Connection: Use approved gas piping materials; pressure test for leaks.
3. Electrical: 120V AC power supply with proper grounding; dedicated circuit recommended.
4. Venting: PVC or approved plastic vent pipe for high-efficiency operation.
5. Ductwork: Properly sized return and supply ducts for optimal airflow.

WARNING! Installation must be performed by qualified HVAC technician. Improper installation can cause fire, explosion, or carbon monoxide poisoning.

First-Time Setup

Initial startup and system verification procedures.

1. Verify all connections: Gas, electrical, venting, and ductwork.
2. Check gas pressure: Adjust manifold pressure per specifications.
3. Test safety controls: Verify pressure switches, limit controls, and flame rollout.
4. Start sequence: Turn on power, set thermostat to heat mode.
5. Monitor operation: Check for proper ignition, flame characteristics, and venting.

CAUTION! Never bypass safety controls. Complete combustion analysis required for proper setup.

Technical Specifications

• Input Capacity: 40,000 - 120,000 BTU/H (model dependent)
• AFUE Rating: Up to 96%
• Gas Type: Natural Gas (may be convertible to LP)
• Electrical: 120V AC, 60Hz, 1.5-5.0 Amps
• Blower Motor: Multi-speed PSC or ECM
• Venting: 2" - 3" PVC/CPVC for concentric or separate intake/exhaust
• Static Pressure: 0.1 - 0.8 in. w.c.
• Temperature Rise: 35°F - 65°F
• Dimensions: Varies by model (typical: 21"W x 21"D x 45"H)

Controls and Settings

Integrated control board manages all furnace operations with diagnostic capabilities.

Thermostat Connections: R (24V), W (Heat), G (Fan), C (Common), Y (Cooling if applicable)

Blower Speeds: Adjustable taps for heating and cooling modes. Gas Valve: Manifold pressure adjustment screw (typically 3.5" w.c. natural gas). Limit Controls: Automatic reset high temperature limits. Pressure Switches: Verify draft inducer operation. Diagnostic LED: Flash codes indicate system status and fault conditions.

Venting and Combustion Air

Proper venting is critical for safe operation and efficiency.

1. Vent Pipe: Use only approved materials (PVC, CPVC, ABS) per local codes.
2. Vent Configuration: Horizontal or vertical termination with proper clearances.
3. Combustion Air: Provide adequate fresh air supply for proper combustion.
4. Vent Length: Follow manufacturer guidelines for maximum equivalent feet.
5. Termination: Maintain proper clearances from windows, doors, and air intakes.

Tip: Always install carbon monoxide detectors when installing gas appliances.

Operating Instructions

Normal heating cycle operation and user controls.

1. Thermostat Setting: Set to desired temperature and HEAT mode.
2. Start Sequence: Draft inducer starts, pressure switch verifies, igniter heats.
3. Ignition: Gas valve opens, burner lights, flame sensor confirms.
4. Blower Operation: Blower starts after heat exchanger warm-up period.
5. Shutdown: Burner shuts off when thermostat satisfied, blower continues for cool-down.

WARNING! Never operate furnace with access panels removed. Keep combustible materials away from furnace.

Maintenance Procedures

Regular maintenance ensures optimal performance and safety.

Annual maintenance by qualified technician recommended. Includes: filter replacement, blower cleaning, heat exchanger inspection, burners cleaning, flame sensor cleaning, safety control testing, vent system inspection, and combustion analysis.

CAUTION! Turn off gas and electrical power before performing any maintenance. Only qualified personnel should service gas controls.

Regulatory Information

ANSI Z21.47/CSA 2.3: Certified for natural gas operation. UL listed. Must be installed in accordance with National Fuel Gas Code (NFPA 54), National Electrical Code (NFPA 70), and local building codes. Manufactured to comply with U.S. Department of Energy efficiency standards. For technical support, contact manufacturer or visit website.

Troubleshooting

Reset: Power cycle furnace to clear temporary lockouts.

Service: Contact qualified HVAC technician for complex issues or gas-related problems.