Ruud Gas Furnace Manual

The Ruud Gas Furnace is a high-efficiency heating system designed for residential use, featuring advanced combustion technology, multiple safety systems, variable-speed blower motor, electronic ignition, and compatibility with various thermostat systems. Below are key sections for safety, features, installation, operation, maintenance, and troubleshooting.

Features at a Glance

Key components: Heat exchanger, blower assembly, gas valve, ignition system, pressure switches, flame sensor, limit switches.

Feature	Description
Heat Exchanger	Stainless steel primary and secondary heat exchangers
Blower Motor	Variable-speed ECM motor for efficient airflow
Ignition System	Hot surface ignition for reliable startup
Gas Valve	Modulating gas valve for precise temperature control
Pressure Switches	Safety switches to verify proper venting
Flame Sensor	Monitors burner flame during operation
Limit Switches	Prevents overheating by shutting off burners
Control Board	Microprocessor-based control system
Air Filter	Standard 1-inch or 4-inch media filter
Vent System	PVC venting for sidewall or roof termination

Installation

Unpack and inspect contents. Install in approved location with proper clearances.

1. Location: Install in well-ventilated area with minimum clearances as specified.
2. Gas Connection: Use approved gas piping; pressure test for leaks.
3. Electrical: Connect to 120V AC power supply with proper grounding.
4. Venting: Install PVC vent pipes according to local codes and manufacturer specifications.
5. Drain Line: Connect condensate drain line to proper drainage.

WARNING! Installation must be performed by qualified HVAC technician. Gas leaks can cause explosion or fire.

First-Time Setup

Power on furnace; follow startup sequence.

1. Thermostat Setup: Install compatible thermostat and configure settings.
2. Gas Pressure: Verify and adjust gas pressure to specifications.
3. Airflow: Set blower speeds for heating mode.
4. Safety Check: Test all safety controls and limit switches.
5. Combustion Analysis: Verify proper combustion and efficiency.

CAUTION! Only qualified technicians should perform initial setup and adjustments.

Specifications

• Heating Capacity: 40,000 to 120,000 BTU/h models available
• Efficiency: 80% to 98% AFUE depending on model
• Gas Type: Natural gas or LP/propane (conversion kit required)
• Electrical: 120V AC, 60Hz, 15 amp circuit
• Blower Motor: Variable-speed ECM
• Vent Size: 2-inch or 3-inch PVC
• Filter Size: 16x25x1 or 20x25x1 standard
• Sound Level: As low as 65 dB on high-efficiency models
• Warranty: 10-year heat exchanger, 5-year parts

Controls and Settings

Access control board via front panel. LED status lights indicate system operation.

Control Board: POWER switch, STATUS LED, DIP switches for configuration.

Thermostat Settings: HEAT/COOL/OFF mode, FAN AUTO/ON, temperature setpoint. Blower Settings: Heating speed, cooling speed, continuous fan speed. Limit Settings: High limit temperature, rollout switch reset. Diagnostic Codes: LED flash codes for troubleshooting.

Connecting Thermostat

Compatible with most 24V thermostat systems. Standard wiring: R, W, Y, G, C terminals.

1. Turn off power to furnace before wiring.
2. Connect thermostat wires to control board terminals.
3. Match wire colors to terminal labels (R-red, W-white, etc.).
4. Configure thermostat for gas furnace operation.

Tip: Use programmable thermostat for maximum energy savings.

Operation

Normal heating cycle sequence:

1. Thermostat calls for heat
2. Inducer motor starts and pressure switch closes
3. Hot surface igniter heats up
4. Gas valve opens and burner ignites
5. Flame sensor confirms ignition
6. Blower motor starts after heat exchanger warms
7. System runs until thermostat satisfied
8. Gas valve closes, blower continues for post-purge

WARNING! Never block air vents or returns. Maintain proper airflow.

Maintenance

Regular maintenance ensures efficiency and longevity.

1. Monthly: Check and replace air filter as needed
2. Seasonal: Inspect vent system for obstructions
3. Annual: Professional inspection and cleaning
4. Annual: Check heat exchanger for cracks
5. Annual: Clean flame sensor and burners
6. Annual: Verify gas pressure and combustion

CAUTION! Turn off power and gas supply before performing any maintenance.

Safety Features

Multiple safety systems protect against hazardous conditions:

• Flame rollout switches
• High limit switches
• Pressure switches
• Flame sensor
• Ignition control lockout
• Gas valve safety shutoff

Regulatory Information

UL listed and ANSI certified. Complies with ASHRAE standards. Manufactured to meet or exceed industry safety standards. For technical support, visit www.ruud.com or contact 1-800-722-2102. All installations must comply with local building codes and utility requirements.

Troubleshooting

Symptom	Possible Cause	Corrective Action
Furnace won't start	Power, thermostat, safety switch	Check power supply; verify thermostat setting; reset safety switches.
No heat	Gas supply, ignition	Verify gas valve on; check for ignition attempts; inspect flame sensor.
Short cycling	Dirty filter, limit switch	Replace air filter; check for blocked vents; verify limit switch operation.
Blower won't stop	Thermostat, control board	Check thermostat fan setting; inspect control board relay.
Unusual noises	Motor, blower wheel	Inspect blower assembly; check for loose components; lubricate if applicable.

Reset: Turn power off for 30 seconds then restart.

Service: 1-800-722-2102; www.ruud.com