Johnson Outdoor Wood Furnace Owners Manual

The Johnson Outdoor Wood Furnace is a high-efficiency heating system designed for outdoor installation, featuring durable steel construction, advanced combustion technology, heat exchanger system, water jacket, thermostat controls, safety shut-off mechanisms, and compatibility with existing heating systems. 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. Connecting to Heating System 7. Fuel Requirements 9. Maintenance Schedule 10. Safety Features 11. Regulatory Information 12. Troubleshooting

Features at a Glance

Key components: Heavy-duty steel firebox, Heat exchanger system, Water jacket, Thermostat control panel, Chimney system, Water inlet/outlet ports, Safety pressure relief valve.

Feature	Description
Firebox	Heavy-duty steel construction for durability
Heat Exchanger	Maximizes heat transfer efficiency
Water Jacket	Surrounds firebox for optimal heat absorption
Thermostat Control	Automatic temperature regulation
Chimney System	Stainless steel with spark arrestor
Water Ports	1.5-inch NPT inlet and outlet connections
Pressure Relief Valve	150 PSI safety release
Door Seal	High-temperature rope gasket
Ash Pan	Removable for easy cleaning
Insulation	Ceramic fiber blanket insulation

Installation Requirements

Choose proper location and prepare site according to local codes.

Location: Minimum 25 feet from structures; clear of combustible materials.
Foundation: Level concrete pad or gravel base required.
Plumbing: Connect to existing heating system with proper piping.
Electrical: 120V AC power source for controls and circulator pump.
Chimney: Install according to manufacturer specifications and local codes.

WARNING! Installation must comply with local building and fire codes. Professional installation recommended.

First-Time Setup

Complete installation and prepare for initial operation.

Fill system: Add water and treatment according to manufacturer specifications.
Pressure test: Check for leaks at all connections.
Initial fire: Start with small fire to cure refractory materials.
Thermostat setup: Program desired temperature settings.
Safety check: Verify all safety systems are operational.

CAUTION! Never operate with empty water jacket. Monitor pressure and temperature during initial operation.

Technical Specifications

Heating Capacity: Up to 2500 sq. ft.
Firebox Dimensions: 24" W x 30" H x 18" D
Water Capacity: 40 gallons
Maximum Pressure: 30 PSI operating, 150 PSI relief
Temperature Range: 120°F - 200°F
Chimney: 6-inch diameter stainless steel
Fuel: Seasoned hardwoods (18-24 months dried)
Efficiency: 85% thermal efficiency
Electrical: 120V AC, 60Hz, 5 amps
Weight: 450 pounds (empty)

Controls and Operation

Control panel features: Thermostat dial, Power indicator, High-limit reset, Pump control switch.

Operation: Set desired temperature on thermostat. System automatically maintains water temperature. Load wood through front door. Adjust air intake for combustion control.

Temperature Settings: Minimum 120°F, Maximum 200°F. Safety Systems: High-limit switch, Pressure relief valve, Low-water cutoff. Maintenance Indicators: Ash accumulation, Gasket condition, Water quality.

Connecting to Heating System

Compatible with forced air furnaces, radiant floor systems, and domestic hot water.

Turn off main power and water supply before connections.
Install circulator pump between furnace and heating system.
Connect water lines using proper fittings and insulation.
Install expansion tank and air eliminator.
Pressure test all connections before operation.

Tip: Use anti-freeze in systems subject to freezing temperatures.

Fuel Requirements

Optimal performance requires properly seasoned wood.

Wood Type: Hardwoods preferred (oak, maple, hickory)
Moisture Content: Below 20% for efficient combustion
Size: 16-18 inch lengths, split to 4-6 inch diameter
Storage: Keep dry and covered; allow air circulation
Loading: Do not overload firebox; maintain air space

WARNING! Never burn treated wood, plastics, or garbage. This can damage furnace and create toxic fumes.

Maintenance Schedule

Regular maintenance ensures optimal performance and safety.

Daily: Check water pressure and temperature
Weekly: Remove ashes; inspect door gasket
Monthly: Clean heat exchanger surfaces
Seasonally: Inspect chimney; check water treatment
Annually: Professional inspection recommended

CAUTION! Always allow furnace to cool completely before performing maintenance.

Safety Features

Multiple safety systems protect against overheating and pressure buildup.

Feature	Function
High-Limit Switch	Shuts down system if temperature exceeds safe limits
Pressure Relief Valve	Releases pressure if exceeds 150 PSI
Low-Water Cutoff	Prevents operation if water level is too low
Spark Arrestor	Prevents sparks from exiting chimney
Door Interlock	Ensures door is properly sealed during operation

Regulatory Information

UL Certified to UL 2523 standards. EPA Phase II qualified for emissions. Complies with ASTM International standards for outdoor wood furnaces. Copyright © 2024 Johnson Heating Systems; all rights reserved. For technical support, visit www.johnsonheating.com or contact 1-800-555-HEAT.

Troubleshooting

Symptom	Possible Cause	Corrective Action
No heat output	Circulator pump failure	Check pump power; verify operation; replace if necessary
High pressure reading	Overheating/blockage	Check relief valve; verify water flow; reduce fire
Poor combustion	Wet wood/air restriction	Use seasoned wood; clean air intake; check chimney
Water leaks	Fitting failure/corrosion	Inspect all connections; repair/replace as needed
Excessive smoke	Incomplete combustion	Adjust air intake; use drier wood; clean flue passages

Reset: Turn thermostat to minimum, wait 5 minutes, then reset.

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