Nexus Triumph – Furnace Igniter & Control Board Replacement

A Nexus Triumph furnace replacement quote landed on my bench last week: $1,247 labor plus $340 in parts, all because the shop wanted to swap the whole assembly instead of diagnosing what actually quit. I’ve been pulling into yards long enough to recognize the pattern—owners push these heating systems hard through the cold months, miss the small signs that something’s wearing out, then find themselves without heat at midnight in a snowstorm with no choice but to call the nearest service center and pay whatever they ask. On Nexus Triumph rigs specifically, the igniter and control board fail in tandem often enough that I’ve stopped treating them as separate problems. Catch the early indicators, though, and this becomes a two-part fix you can execute yourself if you’re willing to spend an afternoon with a socket set and a wiring diagram. What follows is my field-tested approach—the same sequence I run through when I’m standing inside someone’s RV and the clock is ticking.

Suburban 232286 Electrode Assembly: The Igniter That Reliably Sparks

The electrode is where ignition starts—when this component burns out, the control board either goes defensive and locks the unit down or floods the error log with fault codes, and either scenario leaves you in the cold. This isn’t a component that fades gradually; it functions or it fails, and I’ve encountered countless owners who attributed a dead igniter to a dead furnace and replaced hardware that didn’t need replacing.

Performance wins

• Spark engages on the first heating call—no lag time, no extended startup sequences that leave you second-guessing whether the replacement worked.
• The wired assembly arrives protected in its original packaging; you don’t get a bare rod that corrodes during shipping or storage.
• Bracket geometry and terminal alignment conform to Suburban spec—no improvising your installation if you’re working on a 2006-model or later SF-series heating unit.

Performance limitations

• Gap dimension specs don’t always ship printed on the packaging—you’ll want a feeler gauge handy and may need to pull the furnace tech sheet or phone Suburban to confirm the 0.125″ spacing.
• When the board is also in decline (which overlaps symptomatically with igniter failure), installing this electrode will prove the control circuit is the real problem, forcing you to order a second part and schedule another service window.

I had one call where the igniter sparked but the pilot flame wouldn’t hold, and I nearly ordered a new furnace core before I realized the electrode gap had drifted to 0.18″ during shipping—a 30-second feeler gauge check would have saved three hours of troubleshooting. Fit For Suburban RV Furnace Parts 232286,Single Probe Gas Furnace Igniters Electrode with Wire Assembly, Camper Furnace For Suburban 232286 Above 934701426 SF-20, SF-25, SF-30, SF-35 (SF Series)

Parts and Tools

• Replacement igniter electrode assembly matched to your Nexus Triumph model (Suburban 232286 or equivalent) — check current price
• Replacement control board for Nexus Triumph furnace (verify part number against your existing board before ordering)
• Wire strippers and crimpers for reconnecting igniter and control board harnesses
• Multimeter capable of reading DC voltage and resistance
• Socket set and wrenches to access furnace mounting bolts and panel fasteners
• Dielectric grease for protecting electrical connections from corrosion

Step-by-Step Instructions

Step 1: Kill power to the furnace at the breaker

Locate your RV’s main electrical panel and flip the breaker controlling the furnace circuit to OFF. Wait 30 seconds to allow any residual charge to dissipate. This prevents shock and protects sensitive control board circuitry during removal. On most Nexus Triumph rigs, the furnace draws from a dedicated 30-amp circuit. If you’re unsure which breaker controls the furnace, turn it off and try the ignition—no spark means you’ve found the right one.

Step 2: Remove the furnace access panel and photograph the wiring

Open your RV’s furnace compartment (usually under a dinette seat or in a basement cabinet). Unbolt the front access panel. Before touching anything, photograph the control board and igniter connections from multiple angles—especially the wire colors and terminal positions. This becomes your reference when reassembling. Note the exact routing of harnesses so you don’t pinch wires during reinstallation.

Step 3: Test the igniter with a multimeter

Set your multimeter to resistance mode (ohms). Disconnect the igniter harness at the control board. Probe the igniter terminals directly. A healthy igniter reads between 40–80 ohms; anything above 200 ohms or an open circuit (infinite resistance) confirms the igniter has failed. If resistance is normal, the control board is likely the culprit. Document your reading before proceeding to removal.

Step 4: Unbolt and disconnect the failed igniter

Locate the igniter electrode assembly inside the combustion chamber—it’s the ceramic-tipped probe mounted near the burner. Unbolt it from its bracket (usually one or two fasteners). Carefully pull the igniter free and disconnect its wire harness. Inspect the ceramic tip for cracks, heavy carbon buildup, or discoloration. Even minor damage disqualifies the igniter. Keep the old unit as a reference for terminal orientation.

Step 5: Install the replacement igniter and reconnect harness

Insert the new igniter into the mounting bracket and hand-tighten the bolts—do not over-torque, as ceramic tips crack easily. Reconnect the wire harness, matching colors to your photograph. Apply a small amount of dielectric grease to the terminals to prevent corrosion. Ensure the igniter tip sits at the correct distance from the burner (typically 1/4 inch); consult your manual if unsure.

Step 6: Remove and replace the control board

Unbolt the control board from its mounting location (usually a side wall of the furnace housing). Disconnect all harnesses—igniter, thermostat, and any safety sensor wires. Photograph each connection before unplugging. Install the replacement board in the same orientation, reconnect harnesses in reverse order, and secure mounting bolts. Double-check that no wires are pinched between the board and housing.

Step 7: Restore power and test ignition sequence

Close the furnace access panel and reinstall any trim pieces. Return to the breaker panel and flip the furnace circuit back ON. Set your thermostat to heat mode and raise the setpoint 5 degrees above room temperature. Listen for the igniter spark—you should hear a distinct clicking sound within 2–3 seconds of the call for heat. The burner should light within 10 seconds. If spark is absent or delayed, turn off the breaker immediately and recheck all harness connections.

Step 8: Verify stable operation and monitor for fault codes

Run the furnace through two complete heating cycles, allowing it to cycle on and off naturally. Check that the flame ignites consistently and the burner shuts down cleanly when the thermostat is satisfied. If your control board has a diagnostic display or LED, confirm no fault codes are present. Feel the furnace housing—it should warm but not overheat. If any codes appear or ignition remains erratic, power down and review all connections against your photographs.