Complete repair guide for the New Horizons – Furnace Igniter & Control Board Replacement. Follow these steps to diagnose and fix the issue yourself.
Parts & Tools You’ll Need
- Suburban/Atwood RV furnace replacement unit
- Furnace igniter electrode assembly
- Furnace sail switch
- Furnace circuit board / control board
- Furnace high-limit switch
- Furnace blower motor (12V DC)
- Propane/CO combo detector alarm
- Digital multimeter (auto-ranging)
Disclosure: This post contains affiliate links. We may earn a commission on qualifying purchases at no extra cost to you.
Step-by-Step Repair Guide
Step 1: Diagnose Furnace Failure Safely
Begin by ensuring your RV is parked on level ground with the engine off and all propane appliances shut down for safety. Use your digital multimeter to test the 12V DC power supply to the furnace circuit board, checking for proper voltage at the main terminals to confirm whether the issue is electrical or mechanical.
Step 2: Disconnect Power and Propane
Turn off the propane supply valve at the tank and disconnect the negative battery terminal to eliminate all electrical power to the furnace system. Wait at least five minutes to allow any residual charge to dissipate from the control board before proceeding with removal.
Step 3: Remove Old Furnace Assembly
Locate the fasteners securing your furnace unit to the RV frame and remove them using appropriate wrenches or sockets. Carefully disconnect the propane line from the burner assembly and the 12V electrical harness, noting the wire positions for reconnection of the replacement unit.
Step 4: Install New Control Board
Position the replacement circuit board in the furnace housing, aligning all mounting holes securely. Connect the sail switch, high-limit switch, and blower motor connectors to their corresponding ports on the new board, referring to the wiring diagram included with your replacement unit.
Step 5: Connect Igniter Electrode Assembly
Insert the new furnace igniter electrode into its mounting bracket within the combustion chamber, ensuring it sits at the correct distance from the burner port. Attach the high-voltage ignition lead firmly to the electrode terminal, checking that the connection is corrosion-free and tight.
Step 6: Reconnect Propane and Electrical
Reconnect the propane supply line to the furnace burner inlet, hand-tightening the fitting before using a wrench for a final quarter-turn to prevent over-tightening. Reattach the 12V electrical harness to the battery negative terminal and verify your propane/CO combo detector is functioning before any system operation.
Step 7: Test Complete Furnace Operation
Turn the propane valve on and set your RV thermostat to heat mode, listening for the igniter spark and observing flame ignition within 10 seconds of the blower engaging. Use your digital multimeter to confirm the control board is receiving proper 12V DC voltage, and verify the sail switch activates the blower motor response when the furnace reaches operating temperature.
Recommended Parts
| Part | Link |
|---|---|
| Suburban/Atwood RV furnace replacement unit | View on Amazon |
| Furnace igniter electrode assembly | View on Amazon |
| Furnace sail switch | View on Amazon |
| Furnace circuit board / control board | View on Amazon |
| Furnace high-limit switch | View on Amazon |
| Furnace blower motor (12V DC) | View on Amazon |
| Propane/CO combo detector alarm | View on Amazon |
| Digital multimeter (auto-ranging) | View on Amazon |