Instruction Manual for Heil High Efficient Furnace Model 3438B

The Heil High Efficient Furnace Model 3438B is a high-efficiency gas furnace designed for residential heating applications. Featuring advanced combustion technology, variable-speed blower motor, electronic ignition system, and multiple safety features including flame rollout protection and pressure switches. This furnace operates with up to 96% AFUE efficiency and includes diagnostic LED indicators for easy troubleshooting. 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 Operation 6. Thermostat Connection 7. Maintenance Procedures 8. Safety Features 9. Care & Cleaning 10. Regulatory Information 11. Troubleshooting

Features at a Glance

Key components: Two-stage gas valve, variable-speed ECM blower motor, hot surface ignitor, aluminized steel heat exchanger, multi-port in-shot burners, integrated control board with diagnostic LEDs.

Feature	Description
Two-stage gas valve	Provides efficient low-fire and high-fire operation
Variable-speed ECM blower	Energy-efficient motor with quiet operation
Hot surface ignitor	Electronic ignition for reliable startup
Aluminized steel heat exchanger	Durable construction with extended warranty
Multi-port in-shot burners	Efficient combustion with low emissions
Diagnostic LED indicators	Quick troubleshooting and status monitoring
Pressure switches	Safety monitoring of combustion air flow
Flame rollout switches	Safety protection against flame rollout
Limit switches	Over-temperature protection
Gas valve shutoff	Automatic gas supply interruption in fault conditions

Installation Requirements

Professional installation required. Verify local codes and obtain permits.

Location: Install in dry, clean area with adequate combustion air and service clearance.
Venting: Use approved PVC or CPVC pipe for concentric or two-pipe direct vent system.
Gas connection: Use black iron pipe with proper thread sealant; pressure test for leaks.
Electrical: 120V AC, 60Hz dedicated circuit; proper grounding required.
Ductwork: Size appropriately for home's heating requirements; ensure proper airflow.

WARNING! Gas appliances can produce carbon monoxide. Proper venting and combustion air are critical. Installation must comply with local codes and manufacturer specifications.

First-Time Setup

After installation, perform initial startup and system check.

Gas pressure adjustment: Verify and adjust manifold pressure per specifications.
Blower speed settings: Set appropriate heating and cooling speeds for application.
Thermostat configuration: Connect compatible thermostat; program staging and fan control.
System operation test: Verify proper ignition sequence, flame sensing, and safety controls.
Combustion analysis: Check CO levels and temperature rise within specified ranges.

CAUTION! Only qualified HVAC technicians should perform startup procedures. Verify all safety devices are functional before leaving installation.

Technical Specifications

Model: 3438B High Efficient Furnace
Input Capacity: 60,000-120,000 BTU/H (depending on configuration)
AFUE Efficiency: Up to 96%
Gas Type: Natural Gas (convertible to LP with kit)
Electrical: 120V AC, 60Hz, 5.0 Amps maximum
Blower Motor: Variable-speed ECM, 1/3 to 3/4 HP
Stages: Two-stage heating operation
Venting: Direct vent (PVC/CPVC) or conventional (with approved chimney)
Dimensions: Standard cabinet size with variable height options
Warranty: Limited lifetime heat exchanger, 10 years parts

Controls and Operation

Integrated control board manages all furnace functions with LED status indicators.

Control Board: POWER ON/OFF switch, diagnostic LED (flashing codes), mode selection dip switches, blower speed terminals.

Operation Sequence: Call for heat from thermostat → Inducer motor starts → Pressure switch proves → Hot surface ignitor energizes → Gas valve opens → Flame established → Blower starts after heat exchanger warm-up.

Settings: Heating speeds (low/high stage), cooling speed, continuous fan speed, thermostat type selection, fault code reset.

Thermostat Connection

Compatible with most 24VAC thermostats including two-stage and programmable models.

Turn off power to furnace before connecting thermostat wires.
Connect thermostat wires to control board: R (24V), C (common), W/W1/W2 (heat), G (fan), Y/Y1/Y2 (cool).
Configure control board dip switches for thermostat type (single-stage, two-stage heat).
Restore power and verify proper thermostat operation.

Tip: Use thermostat with appropriate staging capability to maximize efficiency and comfort.

Maintenance Procedures

Regular maintenance ensures optimal performance and longevity.

Monthly: Check and replace air filter as needed.
Annual: Professional inspection and cleaning recommended.
Burner inspection: Clean burners and verify proper flame pattern.
Heat exchanger: Visual inspection for cracks or corrosion.
Blower assembly: Clean blower wheel and housing; lubricate if required.
Venting system: Inspect for obstructions or damage.
Safety controls: Test operation of all limit and pressure switches.
Combustion analysis: Verify efficiency and safe operation.

WARNING! Disconnect power and gas supply before servicing. Only qualified technicians should perform internal maintenance.

Safety Features

Multiple safety systems protect against hazardous conditions.

Flame Rollout Protection: Switches detect flame outside combustion chamber and shut down system.

Pressure Switches: Verify proper inducer operation and venting before allowing gas valve to open.

Limit Switches: Prevent overheating by monitoring heat exchanger temperature.

Ignition Control: Monitors flame presence; shuts off gas if flame not detected.

Gas Valve: Automatic shutoff in fault conditions or power loss.

Care & Cleaning

Regular cleaning maintains efficiency and reliability.

Air Filter: Replace every 1-3 months depending on usage and environment.

External Surfaces: Wipe with damp cloth; avoid harsh chemicals.

Venting: Keep intake and exhaust terminals clear of debris, snow, or obstructions.

Combustion Area: Professional cleaning only; do not attempt to clean burners or heat exchanger.

CAUTION! Never operate furnace without air filter. Keep combustible materials away from furnace.

Regulatory Information

UL listed and ANSI certified for safety and performance. Complies with Department of Energy efficiency standards. Manufactured to meet or exceed industry standards for residential gas furnaces. For technical support or warranty service, contact Heil Heating & Cooling at 1-800-HEIL-HELP or visit www.heil-hvac.com. Installation must comply with National Fuel Gas Code (NFPA 54) and local building codes.

Troubleshooting

Symptom	Possible Cause	Corrective Action
Furnace won't start	Power, thermostat, door switch	Check circuit breaker, thermostat setting, ensure door properly closed.
No heat	Gas supply, ignitor, flame sensor	Verify gas valve on; check for flashing LED codes; clean flame sensor.
Short cycling	Dirty filter, airflow restriction	Replace air filter; check for blocked vents or registers.
Blower not running	Motor, capacitor, control board	Check for power to blower; verify control board signals; test capacitor.
Lockout condition	Safety device activation	Reset power; check LED fault codes; verify safety switch operation.

LED Fault Codes: Steady on = normal operation; 1 flash = pressure switch; 2 flashes = rollout switch; 3 flashes = limit switch; 4 flashes = ignitor failure; 5 flashes = flame sense error.

Service: 1-800-HEIL-HELP; www.heil-hvac.com