Friedrich Furnace Manual

The Friedrich Furnace is a high-efficiency heating system designed for residential and light commercial use, featuring advanced combustion technology, multiple heating stages, variable-speed blower motor, electronic ignition, built-in diagnostics, safety controls, and energy-saving operation modes. Below are key sections for safety, features, installation, setup, 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. Operating Modes 8. Maintenance Procedures 9. Care & Cleaning 10. Regulatory Information 11. Troubleshooting

Features at a Glance

Key components: Heat exchanger, blower assembly, gas valve, ignition system, control board, filter compartment, flue outlet, pressure switches.

Feature	Description
Heat exchanger	Stainless steel construction for efficient heat transfer
Blower assembly	Variable-speed ECM motor for quiet operation
Gas valve	Precise gas flow control with safety shutoff
Ignition system	Electronic hot surface ignition
Control board	Microprocessor-based with diagnostic LEDs
Filter compartment	Standard 1-inch or 4-inch media filter compatible
Flue outlet	PVC venting for high-efficiency operation
Pressure switches	Safety devices monitoring combustion airflow
POWER switch	Main electrical disconnect
Diagnostic LEDs	Status and error code indicators

Installation

Unpack and inspect contents. Position in approved location with proper clearances.

Gas connection: Use approved black iron pipe with drip leg and sediment trap.
Electrical connection: Connect to 120V AC power with proper grounding.
Venting system: Install PVC intake and exhaust pipes per local codes.
Condensate drain: Route to approved drain location with trap.
Thermostat wiring: Connect compatible 24V thermostat.

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.

Check gas pressure: Verify manifold and inlet pressures per specifications.
Test ignition sequence: Observe proper flame establishment.
Configure thermostat: Set heating setpoints and fan operation.
Verify airflow: Check temperature rise across heat exchanger.
Test safety controls: Verify proper operation of limit switches.

CAUTION! Ensure proper ventilation and combustion air supply. Test carbon monoxide detectors.

Specifications

Heating Capacity: 40,000 - 120,000 BTU/h depending on model
Efficiency: 80% - 96% AFUE
Stages: Single-stage, two-stage, or modulating operation
Blower Motor: Variable-speed ECM technology
Electrical: 120V AC, 60Hz, 15A circuit
Gas Type: Natural gas or propane (conversion kit required)
Venting: PVC, CPVC, or ABS depending on efficiency rating
Sound Level: As low as 65 dB in quiet mode
Warranty: 10-year heat exchanger, 5-year parts

Controls and Settings

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

Thermostat Controls: HEAT/COOL/OFF mode, FAN AUTO/ON, temperature setpoints, program schedules.

Heating Stages: Single-stage (on/off), two-stage (low/high), modulating (incremental). Blower Settings: Continuous fan, timed off-delay, airflow adjustments. Diagnostic Codes: LED flash patterns indicate specific error conditions. Safety Controls: High-limit switch, rollout switch, pressure switches, flame sensor.

Connecting Thermostat

Compatible with most 24V thermostats. Standard wiring: R (power), W (heat), G (fan), C (common), Y (cooling).

Turn off power to furnace before wiring.
Match thermostat wires to control board terminals.
Configure thermostat for proper system type (gas furnace).
Test all functions: heating, fan, system mode changes.

Tip: Use programmable thermostat for maximum energy savings.

Operating Modes

Supports multiple heating and fan operations.

Heating Mode: Furnace responds to thermostat heat calls.
Fan Only: Continuous or timed circulation without heat.
Standby: System ready but not actively heating.
Lockout: Safety shutdown requiring manual reset.
Diagnostic: Service mode for troubleshooting.

WARNING! Do not 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.
Seasonal: Inspect burners, heat exchanger, vent system.
Annual: Professional inspection and cleaning.
As needed: Clean flame sensor, check gas pressure.

CAUTION! Always disconnect power before servicing. Gas work requires qualified technician.

Care & Cleaning

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

CAUTION! Do not use water or liquid cleaners. Keep electrical components dry.

Regulatory Information

UL certified for safety standards. ANSI Z21.47 compliant for gas appliances. Meets DOE energy efficiency requirements. Copyright © 2025 Friedrich Air Conditioning Co. All rights reserved. For support, visit www.friedrich.com or contact 1-800-541-6645.

Troubleshooting

Symptom	Possible Cause	Corrective Action
Furnace won't start	Power/thermostat	Check circuit breaker; verify thermostat settings; ensure door switch engaged.
No heat	Gas supply/ignition	Verify gas valve on; check pilot/ignition; inspect flame sensor.
Short cycling	Filter/airflow	Replace dirty filter; check for blocked vents; verify proper airflow.
Blower not working	Motor/controls	Check blower door switch; test capacitor; verify control board signals.
Error codes flashing	System faults	Refer to diagnostic chart; count LED flashes for specific error.

Reset: Power cycle furnace; press reset button if equipped.

Service: 1-800-541-6645; www.friedrich.com