This guide covers the complete furnace igniter and control board replacement procedure for the Keystone Montana – Furnace Igniter & Control Board Replacement. Follow each step carefully to restore reliable heat to your fifth wheel.
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)
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Step-by-Step Repair Guide
Step 1: Disconnect Power and Verify Safety
Before beginning any work, switch off the furnace at the wall thermostat and disconnect the 12V DC power supply from the battery disconnect switch or main panel. Use your digital multimeter set to DC voltage mode to confirm zero voltage at the furnace control board terminals, ensuring no residual power remains that could damage components or cause injury.
Step 2: Access the Furnace Control Board Assembly
Locate the furnace unit beneath or behind the kitchen cabinetry in your Montana model, then remove the access panel by unscrewing the four corner fasteners. Document the wire harness connections with photos or a labeled diagram before disconnecting anything, as the control board typically has 6-8 terminal connections for power, igniter, sail switch, and blower motor.
Step 3: Test Igniter Electrode and Measure Resistance
Set your digital multimeter to the ohms (resistance) setting and probe the igniter electrode assembly leads to establish a baseline resistance reading, which should measure between 4-6 ohms on a functioning component. If the reading exceeds 10 ohms or shows infinite resistance, the igniter electrode assembly requires replacement; if resistance is normal, proceed to test the control board circuits.
Step 4: Remove and Replace Faulty Control Board
Disconnect all wire harnesses from the old furnace circuit board by gently prying the push-pin connectors with a small screwdriver, then unbolt the board from its mounting bracket using a 10mm socket. Install the new furnace control board in reverse order, ensuring each connector clicks firmly into place and the board sits flush against the mounting surface to prevent arcing or loose connections.
Step 5: Install New Furnace Igniter Electrode Assembly
Unscrew the ceramic igniter electrode assembly from the burner box (typically secured with a single 1/4-inch bolt), then carefully insert the new electrode so the tip sits 1/8 inch from the burner assembly as specified in your Montana manual. Reconnect the igniter leads to the control board terminals, ensuring the wires are routed away from hot surfaces and secured with cable clips to prevent vibration damage.
Step 6: Verify All Connections and Safety Switches
Inspect the sail switch, high-limit switch, and blower motor connections to confirm each harness is fully seated and color-coded wires match the original configuration. Check that the propane/CO combo detector alarm is functioning (you should hear a brief chirp when power is restored), and confirm the furnace access panel is fully secured before proceeding to final testing.
Step 7: Perform Full System Test and Ignition Cycle
Restore 12V DC power to the furnace and activate the thermostat to initiate a complete heating cycle, listening for the blower motor startup (should run at full speed within 30 seconds) and the igniter electrode clicking sound (rapid spark generation lasting 3-5 seconds). If the burner ignites smoothly and the high-limit switch cycles properly as the furnace reaches operating temperature, the repair is complete; if the igniter fails to spark or the control board does not sequence through the startup cycle, review all connector seating and repeat the multimeter resistance tests on the new igniter electrode.
Recommended Parts & Affiliate Links
| 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 |