The calls I get on holiday weekends are always the same energy: a family parked at a campground, kids in the background, and a very stressed adult trying to describe a sound or a symptom over the phone. I always ask the same first question: when did you first notice something was off? The answer is almost never “today.” With the Grand Design Reflection’s furnace, it’s usually a story that started weeks earlier — a delayed ignition, a faint clicking that went nowhere, or a unit that fired up fine at home but decided a freezing Friday night at elevation was the perfect time to quit for good. The furnace igniter and control board are the two components I see fail most often in this system, and when one goes, it can mask whether the other is the real culprit — which is exactly why I put this guide together the way I did, walking through diagnosis first so you’re not throwing parts at a problem you haven’t actually identified yet.
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 Issues Safely
Turn off your RV’s propane supply at the tank and disconnect the negative battery terminal to ensure complete power shutdown. Use your digital multimeter to test for any residual voltage in the furnace circuit, and inspect the igniter electrode for visible cracks, corrosion, or blackening that indicates failure.
Step 2: Remove Old Furnace Components
Disconnect all wire harnesses from the furnace, taking photos for reference before removal. Unbolt the furnace mounting brackets from the RV frame and carefully slide the unit out, noting the position of all gaskets and seals for reinstallation.
Step 3: Replace Igniter Electrode Assembly
Locate the igniter electrode terminal on the furnace and unscrew the mounting hardware holding the old electrode in place. Install the new furnace igniter electrode assembly, ensuring it sits at the correct gap (typically 3-4mm) from the burner flame sensor, then secure with the original fasteners.
Step 4: Install New Furnace Control Board
Remove the old circuit board by unbolting it from the furnace chassis and disconnecting its wire terminals. Mount the new furnace control board in the identical position, carefully reconnecting each wire harness according to your reference photos and the manufacturer’s wiring diagram.
Step 5: Check Safety Switch Components
Test your sail switch and high-limit switch with the digital multimeter to verify they’re functioning properly before reassembly. Replace either component if the multimeter shows no continuity when the switches are in their closed position.
Step 6: Reinstall Furnace and Connections
Slide the furnace back into its original position, ensuring all gaskets and seals are properly seated before bolting the mounting brackets. Reconnect all wire harnesses to the new control board, reattach the propane line, and verify the blower motor connections are secure.
Step 7: Test System Operation Fully
Reconnect the negative battery terminal and turn the propane supply back on, then set your thermostat to heating mode and listen for the igniter clicking and burner ignition. Confirm the blower motor activates after a 30-second delay and verify your propane/CO detector shows normal operation with no alarms.
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 |