Coleman Furnace 7665 856 Manual

The Coleman Furnace 7665 856 is a high-efficiency gas furnace designed for residential heating applications. This model features advanced combustion technology, multiple heating stages, variable-speed blower motor, electronic ignition system, built-in diagnostics, and compatibility with standard thermostat controls. Below are key sections for safety, features, installation, operation, maintenance, and troubleshooting.

1. Features at a Glance 2. Installation 3. First-Time Setup 4. Specifications 5. Controls and Settings 6. Connecting Thermostat 7. Operation 8. Maintenance Procedures 9. Care & Cleaning 10. Regulatory Information 11. Troubleshooting

Features at a Glance

Key components: Gas valve assembly, heat exchanger, blower motor, electronic control board, pressure switches, flame sensor, igniter, filter compartment.

Feature	Description
Gas valve	Precision gas flow control with safety shutoff
Heat exchanger	Stainless steel construction for durability
Blower motor	Variable-speed ECM motor for efficiency
Control board	Microprocessor-based with diagnostic LEDs
Pressure switches	Safety verification of proper venting
Flame sensor	Monitors burner operation
Hot surface igniter	Electronic ignition system
Filter compartment	Standard 1-inch filter access
Diagnostic lights	LED status indicators for troubleshooting
Safety switches	Door interlock and high-limit protection

Installation

Unpack and inspect contents. Ensure proper location with adequate clearance.

Gas connection: Use approved gas piping; pressure test for leaks.
Electrical connection: Connect to 120V AC power supply with proper grounding.
Vent system: Install approved PVC vent pipes per local codes.
Ductwork: Connect supply and return ducts securely.
Condensate drain: Install drain line with proper slope.

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.

Verify gas supply: Ensure gas valve is open and pressure is correct.
Check electrical: Confirm proper voltage at unit.
Test operation: Set thermostat to heat mode above room temperature.
Monitor ignition: Observe proper burner ignition sequence.
Check airflow: Verify adequate airflow through registers.

CAUTION! Never bypass safety controls. Ensure proper combustion air supply.

Specifications

Heating Capacity: 65,000 BTU/hr input
Efficiency: 80% AFUE
Gas Type: Natural gas (convertible to LP)
Electrical: 120V AC, 60Hz, 5 amps
Blower Motor: Variable-speed ECM
Stages: Single-stage heating
Vent Size: 2-inch PVC
Filter Size: 16x25x1 inches
Dimensions: Standard upflow configuration
Warranty: 20-year heat exchanger, 5-year parts

Controls and Settings

Access control board via front panel. Status lights indicate system operation.

Control Board: POWER, STATUS LED, FAULT LED, RESET button.

Heating: Single-stage operation with variable blower speeds. Fan Control: AUTO/ON settings. Temperature Rise: Factory set for optimal efficiency. Limit Controls: Automatic high-temperature shutdown. Diagnostic Codes: LED flash patterns indicate specific faults.

Connecting Thermostat

Standard 24V thermostat connection with R, W, G, C terminals.

Turn off power to furnace before wiring.
Connect thermostat wires to control board terminals.
Match wire colors to terminal labels (R-red, W-white, G-green, C-common).
Secure connections and restore power.

Tip: Use programmable thermostat for optimal efficiency and comfort.

Operation

Normal heating cycle sequence.

Thermostat calls for heat: Sends signal to control board.
Inducer motor starts: Creates draft through heat exchanger.
Pressure switch verification: Confirms proper venting.
Igniter heats: Hot surface igniter glows.
Gas valve opens: Fuel flows to burners.
Ignition: Burners light and flame sensor confirms.
Blower starts: Circulates warm air through ducts.
Cycle completion: Thermostat satisfied, system shuts down.

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

Maintenance Procedures

Regular maintenance ensures optimal performance and safety.

Monthly: Check and replace air filter as needed.
Annual: Professional inspection and cleaning.
Seasonal: Verify proper operation before heating season.
Visual inspection: Check for soot, corrosion, or damage.

Care & Cleaning

Turn off power and gas supply before cleaning. Use soft brush and vacuum for dust removal.

CAUTION! Do not use water or chemical cleaners on electrical components. Keep burners and heat exchanger clean.

Regulatory Information

UL listed and ANSI certified. Complies with national fuel gas codes and safety standards. Manufactured to meet ENERGY STAR requirements where applicable. For technical support, contact Coleman HVAC at 1-800-426-5362 or visit www.colemanac.com.

Troubleshooting

Symptom	Possible Cause	Corrective Action
Furnace won't start	Power, thermostat, door switch	Check circuit breaker, thermostat setting, door panel secure
No heat	Gas supply, igniter, flame sensor	Verify gas valve open, check igniter, clean flame sensor
Short cycling	Filter, limit switch, airflow	Replace filter, check for blocked vents, verify proper airflow
Blower won't stop	Thermostat, control board	Check thermostat fan setting, inspect control board
Unusual noises	Motor, blower wheel, ducts	Inspect blower assembly, check for loose components

Reset: Power cycle unit if lockout occurs.

Service: 1-800-426-5362; www.colemanac.com