Duo Therm Oil Furnace Manual

The Duo Therm Oil Furnace is a high-efficiency heating system designed for residential and commercial use, featuring advanced combustion technology, multiple heat settings, safety controls, and energy-saving modes. Below are key sections for safety, features, installation, operation, maintenance, and troubleshooting.

1. Features at a Glance 2. Installation 3. First-Time Setup 4. Specifications 5. Controls and Settings 6. Connecting to HVAC System 7. Operating Modes 8. Safety Features 9. Maintenance & Cleaning 10. Regulatory Information 11. Troubleshooting

Features at a Glance

Key components: High-efficiency combustion chamber, oil burner assembly, heat exchanger, blower motor, thermostat connection, safety controls, and filter system.

Feature	Description
Combustion Chamber	Stainless steel construction for efficient heat transfer
Oil Burner	High-pressure nozzle system with adjustable flame
Heat Exchanger	Multi-pass design for maximum heat extraction
Blower Motor	Variable speed for optimal airflow control
Thermostat Connection	Compatible with standard 24V HVAC thermostats
Safety Controls	Flame sensor, high-limit switch, pressure switch
Filter System	Replaceable air filter for clean operation
POWER	Main power switch and indicator light
RESET	Safety reset button for burner system
MODE SELECT	Heat settings and fan control options

Installation

Unpack and inspect all components. Ensure proper clearances and ventilation.

Position furnace: Place on stable, level surface with proper clearances (minimum 18 inches from combustible materials).
Connect oil supply: Install oil line with proper filter and check valve.
Connect venting: Install flue pipe with proper slope and termination.
Electrical connections: Connect to 120V AC power and thermostat wiring.
Fill oil tank: Prime oil line and check for leaks.

WARNING! Installation must be performed by qualified technician. Follow all local codes and regulations.

First-Time Setup

Power on furnace; follow startup procedure.

Power up: Turn on main power switch; check indicator lights.
Thermostat setup: Set thermostat to desired temperature; verify communication.
Initial firing: System will attempt ignition; observe flame pattern.
Adjust settings: Set heat output and fan speed as needed.
Test safety controls: Verify proper operation of all safety features.

CAUTION! Ensure proper ventilation and check for oil leaks before operation.

Specifications

Heating Capacity: 85,000 - 150,000 BTU/hr
Fuel Type: No. 2 Heating Oil
Efficiency: 85% AFUE
Electrical: 120V AC, 60Hz, 5 Amps
Oil Consumption: 0.65 - 1.2 gallons per hour
Airflow: 800 - 1400 CFM
Dimensions: 28" W x 48" H x 24" D
Weight: 185 lbs
Operating Temp Range: -30°F to 120°F

Controls and Settings

Access control panel via front cover. Main Controls: POWER switch, RESET button, MODE SELECTOR.

Thermostat Settings: HEAT/COOL/OFF, FAN AUTO/ON, Temperature setting.

Heat Settings: LOW, MEDIUM, HIGH heat output. Fan Control: AUTO (thermostat controlled) or CONTINUOUS. Safety: Flame sensor monitors burner; high-limit switch prevents overheating; pressure switch ensures proper draft.

Connecting to HVAC System

Ductwork: Connect supply and return ducts. Thermostat: Standard 24V connection.

Turn off power before making connections.
Connect ductwork: Secure supply and return air ducts.
Wire thermostat: Connect R, W, G, C terminals.
Connect oil line: Use proper oil-resistant tubing.
Vent connection: Install flue pipe with proper clearances.

Tip: Ensure all connections are tight and leak-free before operation.

Operating Modes

Supports multiple heating modes and fan settings.

Heat Mode: Select HEAT on thermostat; furnace ignites when heat demanded.
Fan Mode: FAN AUTO (runs with heat cycle) or FAN ON (continuous operation).
Heat Settings: LOW for mild weather, MEDIUM for normal, HIGH for extreme cold.
Standby Mode: System ready but not actively heating.
Safety Shutdown: Automatic shutdown if fault detected.

WARNING! Do not override safety controls. Regular maintenance required.

Safety Features

Flame Sensor: Detects flame presence; shuts off oil if no flame. High-Limit Switch: Prevents overheating. Pressure Switch: Ensures proper draft before ignition. Reset Button: Manual reset after safety shutdown.

Maintenance & Cleaning

Turn off power before servicing. Regular maintenance schedule:

Monthly: Check and replace air filter
Seasonal: Clean heat exchanger and burner assembly
Annual: Professional inspection and nozzle replacement
As needed: Clean oil filter and check nozzle

CAUTION! Use only approved replacement parts. Keep area around furnace clear.

Regulatory Information

UL Certified: Meets UL 727 standards for oil-fired furnaces. EPA Compliant: Meets emissions standards for residential heating equipment. Copyright © 2025 Duo Therm; all rights reserved. For technical support, visit www.duotherm.com or contact 1-800-555-HEAT.

Troubleshooting

Symptom	Possible Cause	Corrective Action
No heat	Power/no oil/thermostat	Check power supply; verify oil supply; check thermostat setting.
Furnace locks out	Safety shutdown	Press RESET button; check for blocked vent or dirty filter.
Smoke or odor	Dirty burner	Clean burner assembly; check heat exchanger.
Noisy operation	Blower issues	Check blower wheel; lubricate motor if applicable.
Frequent cycling	Filter/thermostat	Replace air filter; check thermostat location and calibration.

Reset Procedure: Turn off power, wait 5 minutes, turn power back on, press RESET if needed.

Service: 1-800-555-HEAT; www.duotherm.com