Atwood 8531 Furnace Manual

The Atwood 8531 is a high-efficiency RV furnace designed for reliable heating in recreational vehicles. This furnace features electronic ignition, multiple heat settings, built-in safety controls, and operates on 12V DC with propane fuel. 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 Power and Fuel 7. Operating the Furnace 8. Maintenance Procedures 9. Safety Features 10. Regulatory Information 11. Troubleshooting

Features at a Glance

Key components: Electronic ignition system, thermostat control, combustion chamber, blower motor, safety shut-off valve, and exterior vent.

Feature	Description
Electronic Ignition	No standing pilot light for improved safety and efficiency
Thermostat Control	Precise temperature regulation
Blower Motor	Distributes heated air throughout RV
Safety Shut-off Valve	Automatically cuts gas supply if flame is lost
Combustion Chamber	Stainless steel construction for durability
Exterior Vent	Dual-port design for intake and exhaust
Multiple Heat Settings	Adjustable output for different heating needs
12V DC Operation	Compatible with standard RV electrical systems
Propane Fuel	Clean-burning fuel source
Built-in Diagnostics	LED indicator for troubleshooting

Installation

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

Mounting: Secure furnace in designated compartment with proper clearances.
Vent installation: Connect exterior vent with proper sealing.
Gas line connection: Use approved propane fittings and leak test all connections.
Electrical connection: Connect to 12V DC power source with proper fuse protection.
Ductwork: Install heating ducts according to RV manufacturer specifications.

WARNING! Installation must be performed by qualified technician. Propane systems can be dangerous if improperly installed.

First-Time Setup

After installation, perform initial startup procedure.

Check all connections: Verify gas lines and electrical connections are secure.
Ventilation check: Ensure exterior vent is clear of obstructions.
Power on: Turn on 12V DC power to furnace.
Thermostat setup: Set thermostat to desired temperature.
Initial ignition: System will attempt ignition sequence automatically.

CAUTION! Always check for gas leaks before initial startup. Use soapy water solution on connections.

Specifications

Model: Atwood 8531
Fuel Type: Propane (LPG)
Input Rating: 16,000 BTU/hour
Electrical: 12V DC, 4.5 amps
Dimensions: 14.5" x 9.5" x 7.5"
Weight: 12.5 lbs
Airflow: 120 CFM maximum
Vent Size: 3-inch diameter
Operating Temp Range: -40°F to 140°F
Warranty: 2 years limited

Controls and Settings

Primary control through RV thermostat. Built-in control board manages ignition sequence and safety functions.

Thermostat Controls: Temperature setting, fan mode (auto/on), system on/off.

Operation Sequence: Thermostat calls for heat → Blower motor starts → Pressure switch verifies airflow → Gas valve opens → Igniter activates → Flame sensor confirms ignition → Main burner operates.

Safety Settings: Automatic shut-off if flame is lost, over-temperature protection, airflow verification.

Connecting to Power and Fuel

Proper connections are critical for safe operation.

Power Connection: Connect to 12V DC RV electrical system with 15-amp fuse.
Gas Connection: Use approved propane fittings with thread sealant.
Grounding: Ensure proper electrical grounding.
Vent Connection: Secure exterior vent with proper sealing.

Tip: Always turn off propane supply and disconnect power before servicing connections.

Operating the Furnace

Normal operation through thermostat control.

Set thermostat to desired temperature above current room temperature.
System will begin ignition sequence automatically.
Blower motor will start to purge combustion chamber.
Igniter will activate and gas valve will open.
Once flame is established, main burner will operate until thermostat is satisfied.
System will cycle on/off to maintain set temperature.

WARNING! Never operate furnace with blocked vents or if you smell gas. Shut off immediately and ventilate area.

Maintenance Procedures

Regular maintenance ensures optimal performance and safety.

Annual inspection by qualified technician
Clean combustion chamber and heat exchanger
Check and clean blower wheel
Inspect and clean exterior vent
Verify proper gas pressure
Test all safety controls
Check electrical connections

CAUTION! Always disconnect power and shut off gas supply before performing maintenance.

Safety Features

Multiple safety systems protect against hazardous conditions.

Safety Feature	Function
Flame Sensor	Detects presence of flame and shuts off gas if flame is lost
Over-temperature Switch	Shuts off furnace if excessive temperatures are detected
Pressure Switch	Verifies proper airflow before allowing ignition
Gas Valve	Automatically closes if electrical power is interrupted
Vent Safety	Prevents operation if vent is obstructed

Regulatory Information

UL certified for RV use. Complies with ANSI Z21.44 standards for gas-fired recreational vehicle heaters. CSA certified for Canadian market. Manufactured by Atwood Mobile Products. For technical support, contact 1-800-888-3378 or visit www.atwoodmobile.com.

Troubleshooting

Symptom	Possible Cause	Corrective Action
Furnace won't start	Power issue/thermostat	Check 12V power supply; verify thermostat setting; check fuse
Blower runs but no heat	Gas supply/ignition	Check propane supply; verify gas valve operation; check igniter
Short cycling	Airflow/overheating	Clean air filter; check for blocked vents; verify proper clearances
Noisy operation	Blower/motor	Clean blower wheel; check for obstructions; lubricate if applicable
Gas odor	Leak/malfunction	Shut off immediately; ventilate area; check for gas leaks
Error code flashing	System fault	Refer to diagnostic chart in service manual; count LED flashes

Reset: Turn thermostat off for 5 minutes, then restart.

Service: 1-800-888-3378; www.atwoodmobile.com