Here’s what most RV owners don’t realize until they’re trying to sell: neglected mechanical systems tank resale value faster than almost anything else. A rig with clean cosmetics and a history of deferred maintenance sells for thousands less than one that’s a little road-worn but mechanically solid. I’ve bought plenty of both. The Keystone Sprinter’s furnace is one of those systems that gets ignored until it flat-out quits — usually because a failing igniter throws a lockout code, or a worn control board starts cycling erratically, and the owner just stops using the heat instead of fixing it. By the time that rig hits the market, the furnace hasn’t run in two seasons, and you can bet I’m factoring every bit of that into my offer price. This guide walks you through diagnosing and replacing the igniter and control board yourself — the right way, with the kind of detail that comes from actually doing this repair more than once, not just summarizing a service manual.
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: Diagnose Furnace Ignition Failure
Before beginning any repairs, verify that your Keystone Sprinter’s furnace isn’t producing heat and listen for clicking sounds from the igniter when you turn on the heating system. Ensure the propane tank has adequate fuel and check that the 12V DC power is reaching the furnace by using your digital multimeter to test voltage at the main connector. Disconnect the negative battery cable to cut all power to the furnace system and work in a well-ventilated area away from any ignition sources.
Step 2: Access Furnace Housing Components
Locate your RV’s furnace compartment, typically found in a basement cabinet or utility space, and remove the cover panel by unscrewing the fasteners around its perimeter. Take photos or label all wire connections to the igniter electrode and control board before disconnecting anything, as you’ll need to match these connections during reinstallation. Remove any insulation wrapping around the furnace unit to gain clear access to the igniter assembly and circuit board.
Step 3: Remove Old Igniter Electrode Assembly
Disconnect the two electrical wires attached to the igniter electrode by gently pulling the connectors apart, noting their original positions for reference. Locate the mounting bracket holding the igniter electrode assembly, typically secured with one or two screws, and remove these fasteners completely. Carefully slide the old igniter electrode assembly out from the furnace housing, being cautious not to damage the ceramic electrode tip or surrounding components.
Step 4: Install New Igniter Electrode Unit
Position the new furnace igniter electrode assembly into the mounting bracket, aligning the electrode tip with the burner assembly opening at the proper gap distance. Secure the new igniter with the original mounting screws, ensuring it’s firmly seated and won’t vibrate loose during furnace operation. Reconnect the two electrical wires to the new igniter electrode, matching the wire colors and positions to your reference photos from the previous steps.
Step 5: Replace Furnace Control Board
Disconnect all electrical connectors from the old furnace control board by carefully pulling each connector straight away from its socket and documenting their positions with photos. Remove the mounting screws securing the control board to the furnace frame and lift the old board out of the unit. Install the new furnace circuit board by reversing this process, seating it firmly in the mounting brackets and reconnecting all wires in their original positions.
Step 6: Verify Sail Switch and Safety Devices
Check the furnace sail switch (airflow detection switch) for proper operation by gently moving the sail blade to ensure it moves freely without sticking. Test the furnace high-limit switch by using your multimeter to verify continuity—it should show a closed circuit at room temperature and open when heated. Inspect the propane/CO combo detector alarm for proper operation and ensure its battery is fresh, as this device is critical for your safety.
Step 7: Test Furnace System Operation
Reconnect the negative battery cable and power on the RV electrical system, then turn the furnace thermostat to heat mode and set the temperature above room level. Listen for the blower motor to engage and watch for the igniter electrode to glow red within a few seconds before the main burner ignites. Allow the furnace to run for 5-10 minutes, verify hot air flows from the vents, and confirm the propane/CO detector shows no alarms before closing up the furnace compartment.
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 |