When you boondock regularly — no hookups, no campground services, no one nearby to help — you develop a different relationship with your rig’s systems than a weekend camper does. Everything has to work. You learn the failure modes, the warning signs, and the repairs before you need them, not during. The furnace is one of those systems you simply cannot afford to lose — not when you’re parked at elevation in October and the temperature drops to 28° overnight — and in the Keystone Arcadia, the most common reason a furnace stops lighting or starts behaving erratically comes down to two components: a worn-out igniter or a failing control board. This guide walks you through diagnosing which one is actually the problem, sourcing the right replacement part, and doing the swap yourself, because when you live in your rig full-time, waiting on a mobile tech or a dealership appointment isn’t always an option you have.
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 Igniter Failure
Start by disconnecting the negative battery terminal to ensure your safety while working on electrical components. Use your digital multimeter to test the igniter electrode for continuity—a reading of infinity ohms indicates a failed igniter that requires replacement.
Step 2: Remove Old Furnace Assembly
Locate your furnace compartment and disconnect all propane and electrical connections carefully, including the control board wiring harness and blower motor leads. Remove the mounting bolts securing the old furnace unit and slide it out completely, noting the position of all components for reinstallation reference.
Step 3: Install New Furnace Unit
Position your replacement Suburban or Atwood furnace unit into the compartment, aligning all mounting holes with the RV frame. Secure the furnace with all mounting bolts tightened firmly, then reconnect the propane line using appropriate fittings and your blower motor electrical leads.
Step 4: Replace Igniter Electrode Assembly
Locate the igniter electrode inside the furnace chamber and disconnect its wiring from the control board. Carefully remove the old electrode by unbolting or unsnapping it from the burner assembly, then install the new igniter electrode in the same position and reattach its wiring securely.
Step 5: Install New Control Board
Remove all electrical connectors from the old control board, photographing or labeling each connection for reference during reinstallation. Mount your new circuit board in the designated location and reconnect all wiring harnesses to their corresponding terminals, ensuring connections are tight and properly seated.
Step 6: Connect Safety Switch Components
Reinstall the sail switch, high-limit switch, and propane/CO combo detector according to your furnace’s schematic diagram. Verify that all switches are positioned correctly and securely fastened, as these components are critical for your furnace’s safe operation and shutdown functions.
Step 7: Test Complete Furnace Operation
Reconnect your negative battery terminal and power on the furnace system, listening for the ignition click and observing flame appearance in the burner chamber. Use your multimeter to verify proper voltage at the blower motor, and confirm that your propane/CO detector sounds properly when tested according to its manufacturer instructions.
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 |