Airtemp VG7SC Furnace Installation Manual

The Airtemp VG7SC is a high-efficiency gas furnace designed for residential heating applications. This variable-speed, multi-stage furnace features advanced combustion technology, electronic ignition, and smart control systems for optimal performance and energy efficiency. Below are key sections covering safety precautions, installation procedures, electrical connections, startup procedures, maintenance, and troubleshooting.

Features at a Glance

Key components: Variable-speed blower motor, multi-stage gas valve, hot surface ignitor, flame sensor, pressure switches, control board, and diagnostic LED.

Safety Precautions

Critical safety information for installers and homeowners.

1. Turn off electrical power and gas supply before installation or service.
2. Wear appropriate personal protective equipment (safety glasses, gloves).
3. Ensure adequate combustion air and proper ventilation.
4. Follow all local building codes and manufacturer specifications.
5. Test for gas leaks after installation using approved methods.

WARNING! Failure to follow safety procedures may result in fire, explosion, carbon monoxide poisoning, or personal injury. Installation must be performed by qualified HVAC technicians.

Pre-Installation Requirements

Site preparation and requirements before installation.

1. Verify furnace size matches heating load calculation.
2. Ensure adequate clearance: 24 inches front, 6 inches sides, 6 inches rear, 24 inches top.
3. Check location for proper drainage and accessibility.
4. Verify gas supply line size and pressure requirements.
5. Confirm electrical service meets furnace requirements.

CAUTION! Improper sizing or installation may void warranty and cause system failure.

Installation Procedures

Step-by-step furnace installation process.

1. Position furnace: Place on level surface or install hanging brackets.
2. Connect ductwork: Secure supply and return air connections.
3. Install gas line: Use black iron pipe with proper thread sealant.
4. Connect electrical: Follow wiring diagram for proper connections.
5. Install venting: Use approved PVC materials for intake and exhaust.
6. Connect condensate drain: Route to appropriate drainage location.

WARNING! Use two people for lifting; furnace is heavy and awkward to handle.

Electrical Connections

Wiring requirements and connections.

1. Disconnect power at main electrical panel before wiring.
2. Connect line voltage: 120V AC, 15 amp dedicated circuit required.
3. Connect low voltage: 24V thermostat wiring (R, W, Y, G, C terminals).
4. Ground furnace: Connect green ground wire to grounding point.
5. Verify polarity: Ensure proper hot and neutral connections.

Tip: Use wire nuts and electrical tape for secure connections. Follow NEC and local codes.

Gas Line Connections

Natural gas or propane connection procedures.

1. Shut off gas supply at main valve.
2. Install sediment trap before gas valve connection.
3. Use pipe dope or Teflon tape rated for gas service.
4. Pressure test: Test at 14 inches WC for natural gas, 11 inches WC for propane.
5. Check for leaks: Use soap solution or electronic gas detector.

WARNING! Never use matches or open flame to check for gas leaks.

Venting System

Intake and exhaust vent installation requirements.

1. Use only approved PVC pipe (Schedule 40 or 80).
2. Maintain proper slope: 1/4 inch per foot toward furnace.
3. Keep vent runs as short and straight as possible.
4. Maintain clearance from windows, doors, and air intakes.
5. Install termination caps according to manufacturer specifications.

CAUTION! Improper venting may cause carbon monoxide buildup and system failure.

Startup and Commissioning

Initial startup procedures and system verification.

1. Restore electrical power and gas supply.
2. Set thermostat to heat mode and raise temperature setting.
3. Verify proper ignition sequence and flame establishment.
4. Check gas pressure: Adjust if necessary per specifications.
5. Measure temperature rise: Should be within 35-65°F range.
6. Verify airflow: Adjust blower speed if required.

WARNING! Monitor first few cycles for proper operation and check for unusual odors or sounds.

Maintenance Guidelines

Routine maintenance for optimal performance.

• Monthly: Check and replace air filter as needed.
• Annual: Professional inspection and cleaning.
• Clean burners and heat exchanger annually.
• Check condensate drain and trap for blockages.
• Verify vent system integrity and clearances.
• Test safety controls and ignition system.

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

Specifications

• Model: VG7SC
• Input Capacity: 40,000 - 120,000 BTU/H
• AFUE Rating: Up to 96%
• Stages: Two-stage heating
• Blower Type: Variable-speed ECM
• Electrical: 120V AC, 60Hz
• Gas Type: Natural gas or propane
• Venting: PVC (2-inch recommended)
• Operating Temp Range: -30°F to 120°F ambient
• Warranty: Limited lifetime heat exchanger, 10 years parts

Troubleshooting

Reset: Turn power off for 30 seconds, then restore to reset control board.

Service: 1-800-AIRTEMP; www.airtemp.com