Rheem Criterion II Gas Furnace Parts Manual

The Rheem Criterion II Gas Furnace is a high-efficiency residential heating system designed for reliable performance and easy maintenance. This manual provides comprehensive information on parts identification, replacement procedures, safety guidelines, and technical specifications for proper furnace maintenance and repair. Below are key sections covering parts overview, installation guidelines, maintenance procedures, and troubleshooting.

1. Parts Overview 2. Installation Guidelines 3. Maintenance Procedures 4. Technical Specifications 5. Control System Components 6. Heat Exchanger Assembly 7. Blower System Parts 9. Safety Features 10. Care & Maintenance 11. Regulatory Information 12. Troubleshooting

Parts Overview

Key components: Heat exchanger assembly, Blower motor and wheel, Gas valve, Ignition system, Control board, Limit switches, Pressure switches, Filter system.

Component	Description
Heat Exchanger	Primary and secondary heat transfer surfaces
Blower Assembly	Includes motor, wheel, and housing
Gas Valve	Regulates gas flow to burners
Ignition System	Hot surface igniter and flame sensor
Control Board	Main system controller and safety circuits
Limit Switches	High temperature safety cutoffs
Pressure Switches	Verify proper venting operation
Filter Rack	Standard 1-inch filter housing
Burners	Stainless steel burner assembly
Ventor Motor	Induced draft blower

Installation Guidelines

Proper installation ensures safe and efficient operation.

Location: Install in clean, dry area with adequate clearance for service access.
Venting: Follow manufacturer specifications for proper vent pipe sizing and routing.
Gas Connection: Use approved pipe compound and leak test all connections.
Electrical: Follow local codes for proper grounding and circuit protection.
Ductwork: Ensure proper sizing and sealing for optimal airflow.

WARNING! Gas furnaces must be installed by qualified technicians only. Improper installation can cause fire, explosion, or carbon monoxide poisoning.

Maintenance Procedures

Regular maintenance ensures optimal performance and safety.

Filter Replacement: Replace filters monthly during heating season.
Blower Cleaning: Clean blower assembly annually.
Heat Exchanger Inspection: Check for cracks or corrosion each season.
Burner Cleaning: Clean burners and inspect flame pattern.
Safety Device Testing: Verify operation of all limit and pressure switches.

CAUTION! Always disconnect power and gas supply before performing maintenance.

Technical Specifications

Input Capacity: 40,000 - 120,000 BTU/H (model dependent)
Efficiency: 80% AFUE standard
Gas Type: Natural gas or LP (with conversion kit)
Electrical: 120V AC, 60Hz, 15 amp circuit
Airflow: 800 - 2000 CFM (model dependent)
Static Pressure: 0.1 - 0.8 in. w.c.
Venting: Category I, PVC or metal venting options
Dimensions: Varies by model (check specific model data)

Control System Components

Main control board manages all furnace operations and safety functions.

Control Board Features: Ignition sequence control, Blower speed control, Safety circuit monitoring, Diagnostic LED indicators, Thermostat interface.

Safety Devices: Flame rollout switch, High limit switch, Pressure switch, Ignition lockout, Blower door safety switch. Diagnostic: LED fault code display, Manual reset capability, Self-diagnostic routines.

Heat Exchanger Assembly

Clamshell design with primary and secondary heat transfer surfaces.

Primary Tubes: Extract initial heat from combustion gases
Secondary Surface: Additional heat extraction for efficiency
Collector Box: Directs flue gases to vent system
Access Panels: Removable for inspection and cleaning

WARNING! Cracked heat exchangers must be replaced immediately to prevent carbon monoxide hazards.

Blower System Parts

Multi-speed direct drive blower for air circulation.

Blower Motor: PSC or ECM motor types
Blower Wheel: Forward-curved design
Motor Mount: Vibration-isolated mounting system
Speed Taps: Multiple speed settings for heating/cooling
Capacitor: Run capacitor for motor operation

Tip: Lubricate motor bearings according to manufacturer schedule (if applicable).

Safety Features

Multiple safety systems ensure safe operation under all conditions.

Safety Device	Function
Flame Rollout Switch	Detects burner flame outside combustion chamber
High Limit Switch	Shuts off burners if overheating detected
Pressure Switch	Verifies proper venting before ignition
Ignition Lockout	Prevents repeated ignition attempts
Door Safety Switch	Shuts down unit when access panels removed

Care & Maintenance

Regular maintenance extends furnace life and ensures efficiency.

Monthly: Check/replace air filter. Annually: Professional inspection and cleaning. Seasonal: Test safety controls and check vent system.

CAUTION! Never operate furnace without filter. Keep combustion air intake clear of obstructions.

Regulatory Information

ANSI Z21.47/CSA 2.3: Certified for safe operation. UL listed components. Meets DOE efficiency standards. For technical support and parts ordering, contact Rheem at 1-800-432-8373 or visit www.rheem.com. Always use genuine Rheem replacement parts for warranty compliance.

Troubleshooting

Symptom	Possible Cause	Corrective Action
Furnace won't start	Power, thermostat, door switch	Check circuit breaker, thermostat setting, door switch engagement
No heat	Gas supply, ignition, limit switch	Verify gas valve on, check igniter, reset limit switches
Blower won't run	Motor, capacitor, control board	Test motor windings, check capacitor, verify control signal
Short cycling	Filter, airflow, overheating	Replace filter, check ductwork, verify proper venting
Unusual noises	Blower, motor, heat exchanger	Inspect blower wheel, motor bearings, heat exchanger for issues

Reset: Power cycle unit to clear lockout conditions.

Service: 1-800-432-8373; www.rheem.com