Coleman 7680 Furnace Manual

The Coleman 7680 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, and comprehensive safety controls. Below are key sections for safety, features, installation, operation, maintenance, and troubleshooting.

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

Features at a Glance

Key components: Heat exchanger, blower assembly, gas valve, igniter, flame sensor, pressure switches, control board, and venting system.

Feature	Description
Heat Exchanger	Stainless steel construction for durability and efficiency
Blower Motor	Variable-speed ECM motor for quiet operation
Gas Valve	Multi-stage gas control for precise heating
Ignition System	Hot surface igniter for reliable startup
Flame Sensor	Safety device to detect burner flame
Pressure Switches	Verify proper venting operation
Control Board	Microprocessor-based control system
Venting System	PVC pipe compatible for sidewall or roof venting
Air Filter	Standard 1-inch or 4-inch media filter compatible
Thermostat Connection	Compatible with standard 24V thermostats

Installation Requirements

Professional installation recommended. Ensure proper clearances and venting.

Location: Install in dry, level area with adequate combustion air and service access.
Venting: Use approved PVC pipe; maintain proper slope and termination clearances.
Gas Connection: Use black iron pipe with drip leg; pressure test for leaks.
Electrical: Connect to 120V AC power; proper grounding required.
Ductwork: Ensure proper sizing and sealing for optimal airflow.

WARNING! Gas appliances can be dangerous if improperly installed. Use qualified HVAC technician.

First-Time Setup

Initial startup must be performed by qualified technician.

Verify installation: Check all connections, clearances, and venting.
Gas pressure: Adjust manifold pressure to specifications (typically 3.5" WC natural gas).
Electrical: Connect thermostat; set system to heating mode.
Test operation: Start furnace and verify proper ignition sequence.
Airflow: Check temperature rise and adjust blower speed if needed.

CAUTION! Never attempt gas adjustments without proper training and equipment.

Technical Specifications

Heating Capacity: 80,000 BTU/hr input
Efficiency: 80% AFUE
Stages: Single-stage heating operation
Blower Motor: PSC or ECM variable speed
Electrical: 120V AC, 60Hz, 15 amp circuit
Gas Type: Natural gas (convertible to LP with kit)
Manifold Pressure: 3.5" WC natural gas
Venting: 2" PVC pipe minimum
Dimensions: Standard upflow configuration
Warranty: 20-year heat exchanger, 5-year parts

Controls and Settings

Integrated control board with LED status light. Access door switch for service safety.

Control Board: LED flash codes for diagnostics, DIP switch settings for blower speeds and timing.

Thermostat Settings: Heat/Off/Auto fan modes. Blower Settings: Adjustable heating and cooling speeds via DIP switches. Limit Controls: Automatic high-limit protection. Pressure Switches: Verify inducer operation and venting.

Operating Instructions

Normal operation controlled by thermostat. System follows predetermined sequence.

Thermostat Call: Set thermostat above room temperature for heat demand.
Inducer Start: Blower purges heat exchanger for 30-60 seconds.
Ignition: Hot surface igniter glows, gas valve opens.
Flame Detection: Flame sensor confirms ignition within trial period.
Blower Operation: Blower starts after heat exchanger warm-up delay.
Cycle Completion: System shuts down when thermostat satisfied.

Tip: Allow system to complete full cycle; frequent cycling reduces efficiency.

Maintenance Procedures

Regular maintenance ensures efficiency and longevity.

Monthly: Check and replace air filter as needed.
Seasonal: Inspect burners, heat exchanger, and venting.
Annual: Professional inspection and cleaning recommended.
Blower: Clean blower wheel and housing annually.
Drain System: Clear condensate trap and drain line.

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

Safety Features

Multiple safety systems protect against hazardous conditions.

Safety Device	Function
Flame Rollout Switch	Detects improper burner flames
High Limit Switch	Prevents overheating
Pressure Switches	Verify proper venting operation
Flame Sensor	Confirms burner ignition
Gas Valve	Automatic shutoff if ignition fails
Door Switch	Disables operation when panel removed

Care & Cleaning

Regular cleaning maintains efficiency and prevents breakdowns.

Air Filter: Replace every 1-3 months depending on usage. Burners: Clean annually with soft brush. Heat Exchanger: Professional inspection for cracks or corrosion. Blower: Vacuum blades and motor annually. Condensate System: Flush with water/vinegar solution.

CAUTION! Never operate without filter. Keep area around furnace clear of combustible materials.

Regulatory Information

ANSI Z21.47/CSA 2.3: Certified for natural and propane gas operation. UL listed for electrical safety. Installation must comply with National Fuel Gas Code NFPA 54 and local building codes. 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 on, check for ignition attempts, clean flame sensor
Short cycling	Dirty filter, limit switch	Replace air filter, check for restricted airflow
Blower won't stop	Thermostat fan setting	Set thermostat fan to AUTO instead of ON
Lockout condition	Safety device tripped	Reset power, check LED error codes

Reset Procedure: Turn thermostat off, wait 5 minutes, restore power, turn thermostat on.

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