Attic Furnace Installation Manual

The Attic Furnace is a high-efficiency heating system designed for attic installation, featuring advanced combustion technology, variable-speed blower motor, electronic ignition, smart thermostat compatibility, safety shutoff switches, and energy-saving modes. Rated for 60,000-120,000 BTU output with AFUE ratings up to 96%. Below are key sections for safety, features, installation, setup, operation, and troubleshooting.

Features at a Glance

Key components: High-efficiency heat exchanger, variable-speed blower, electronic ignition, pressure switches, flame sensor, condensate drain system.

Safety Precautions

Critical safety information for proper installation and operation.

1. Install carbon monoxide detectors in living areas near sleeping quarters.
2. Ensure adequate combustion air and proper ventilation.
3. Keep flammable materials away from furnace and vent pipes.
4. Verify gas line is leak-free before operation.

WARNING! Failure to follow safety precautions can result in fire, explosion, carbon monoxide poisoning, or death. Installation must comply with local codes.

Installation Requirements

Proper installation ensures safe and efficient operation.

1. Location: Must be installed on stable platform in attic with adequate access.
2. Clearances: Minimum 24 inches front, 6 inches sides, 12 inches top, 6 inches rear.
3. Platform: Must support furnace weight plus service technician.
4. Drainage: Condensate line must drain properly with trap installed.
5. Electrical: Dedicated 120V circuit required; proper grounding essential.

CAUTION! Furnace is heavy; use proper lifting equipment and multiple personnel.

Specifications

• Input Capacity: 60,000-120,000 BTU/hr
• AFUE Rating: Up to 96%
• Electrical: 120V, 60Hz, 15A circuit
• Gas Type: Natural gas or propane (conversion kit required)
• Gas Pressure: 3.5" WC natural gas, 10" WC propane
• Blower Motor: ECM variable speed
• Venting: PVC or CPVC required for high-efficiency operation
• Dimensions: 48" H x 21" W x 32" D
• Weight: 150 lbs
• Operating Temp: -30°F to 150°F ambient

Controls and Settings

Integrated control board with diagnostic LED and DIP switch settings.

Control Board: POWER ON/OFF switch, LED status indicators, DIP switches for blower speeds, thermostat connections.

Settings: Heat speed (HIGH/MED/LOW), continuous fan speed, temperature rise adjustment, ignition trial settings. Diagnostic codes: 1 flash (normal), 2 flashes (pressure switch), 3 flashes (ignition failure), 4 flashes (flame sense), 5 flashes (high limit).

Venting System

PVC or CPVC vent pipes required for condensing furnace.

1. Install vent pipes with minimum 1/4" per foot slope toward furnace.
2. Maximum vent length: 50 feet equivalent with two 90° elbows.
3. Use only approved PVC/CPVC cement for joints.
4. Terminate vent 12 inches above anticipated snow level.
5. Maintain 3-foot clearance from windows, doors, and air intakes.

Tip: Test vent system with manometer to ensure proper draft.

Electrical Connections

Proper electrical installation is critical for safe operation.

1. Disconnect power at main panel before making connections.
2. Connect 120V power to designated terminals (L1, L2, GND).
3. Connect thermostat wires to R, W, G, C terminals.
4. Verify proper grounding of furnace chassis.
5. Install appropriate fuse or circuit breaker (15A maximum).

WARNING! Electrical work must be performed by qualified electrician following local codes.

Gas Line Connections

Gas piping must be properly sized and leak-tested.

1. Use black iron or approved CSST gas piping.
2. Install sediment trap before gas valve.
3. Apply pipe thread compound to male threads only.
4. Pressure test at 14" WC for 10 minutes with no drop.
5. Verify manifold pressure: 3.5" WC natural gas.

WARNING! Gas connections must be made by licensed gas fitter. Leak test with soap solution.

Startup Procedure

Follow this sequence for initial furnace startup.

1. Verify all connections are secure and proper clearances maintained.
2. Open gas shutoff valve and verify no leaks.
3. Restore electrical power to furnace.
4. Set thermostat to heat mode above room temperature.
5. Observe ignition sequence: inducer motor, pressure switch, igniter, gas valve.
6. Verify flame establishment and proper burner operation.
7. Check temperature rise and adjust blower speed if necessary.
8. Monitor for proper venting and condensate drainage.

CAUTION! Do not bypass safety controls. If furnace fails to start, diagnose using LED codes.

Maintenance

Regular maintenance ensures optimal performance and longevity.

Monthly: Check air filter, clean if reusable or replace if disposable. Annually: Clean burners and heat exchanger, check flame sensor, verify gas pressure, inspect vent system, clean condensate trap, lubricate inducer motor if required.

CAUTION! Turn off power and gas before performing maintenance. Use only manufacturer-approved parts.

Troubleshooting

Reset: Power cycle furnace at disconnect or circuit breaker.

Service: 1-800-HEAT-HELP; www.atticfurnace.com/support