Tiffin Zephyr – Furnace Igniter & Control Board Replacement

I’ve got my work setup spread across a concrete pad behind bay two at the storage facility where I keep the current rig — socket set hanging on the pegboard, laptop propped on an old toolbox, and a parts catalog open whenever I’m troubleshooting a system that’s gone sideways. Pulled a blackened Suburban igniter electrode out of a Zephyr last month, and that’s when it hit me again: this is the repair that catches Tiffin owners off guard more than almost anything else. The furnace clicks once, maybe twice, then quits entirely. Most people panic, thinking their propane system just took a nosedive. What’s actually happening is the igniter electrode has carbonized or the control board has burned out — both parts are plug-and-play swaps that take a handful of hours and zero dealer markup. After sixty-plus Zephyrs I’ve worked on over the years, I can tell you this isn’t a mystery repair anymore. Walk through it once with the right part in hand, and you’ll save yourself the shop labor and get your heat working again before the next cold front rolls in.

Getting Your Igniter Spark Back: The Electrode Swap

Inside your Zephyr sits a Suburban furnace unit, and that igniter electrode is the flashpoint where propane gas actually ignites. When it goes weak or stops firing altogether, the control board registers no flame and shuts down the whole cycle. Replacing the electrode assembly gets your spark back to full strength and lets the furnace actually do its job.

Where you’ll see the payoff

• Spark comes back hot and loud — that distinctive pop tells you the electrode is firing correctly again and igniting propane on demand.
• The replacement assembly ships with the wire harness already soldered and seated, so you’re not threading connections through a cramped furnace cavity while parked on a slope.
• Zephyr furnace systems use the SF-series Suburban architecture, meaning the part bolts straight in with no adapter shopping or year-model guessing.

Where the job gets tight

• The combustion chamber leaves almost no elbow room — a 7/16″ wrench alone won’t cut it; you’ll need a swivel socket to avoid spinning that mounting nut into a stripped-out hole.
• Aftermarket igniter tips don’t always carry the same electrode gap as OEM, so even after you install one, the spark might look wimpy; a small file and a few minutes of gap adjustment usually fixes it, or you’re wrestling with ignition issues for weeks.

I replaced an igniter on a ’19 Zephyr that looked brand new and still had weak spark, and only realized the gap had been set too wide at the factory — a five-minute adjustment with a feeler gauge solved it. If your furnace still clicks without igniting after swap, check the electrode gap before blaming the part. 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 with wire harness, matched to your Suburban furnace model (232286 for single-probe gas models) — check current price
• Furnace control board replacement (Suburban model-specific), if the electrode swap doesn’t restore spark
• Wire strippers and crimpers for reconnecting the igniter harness to the control board terminals
• Multimeter set to measure DC voltage and resistance, for testing the igniter circuit before and after replacement
• Small flashlight or headlamp to see inside the furnace compartment and access panel
• Socket set and screwdrivers (Phillips and flathead) to remove the furnace access panel and electrode mounting bracket

Step-by-Step Instructions

Step 1: Shut off propane and 120V power to the furnace

Turn the propane tank valve to the off position. Then flip the breaker for the furnace circuit at your main panel, or unplug the furnace power cord if it has one. Wait five minutes to let any residual gas clear. This prevents accidental ignition while you’re working inside the furnace box and keeps you safe from electrical shock when testing circuits.

Step 2: Locate and photograph the igniter electrode assembly

Open the furnace access panel on the side or bottom of your Zephyr’s furnace unit. You’ll see a ceramic or metal rod with a wire harness running back to the control board. Take a clear photo of how the wire connects to the board terminals before you disconnect anything. Note the exact position and color of each wire—this prevents reversed connections during reinstallation.

Step 3: Test the igniter circuit with a multimeter

Set your multimeter to DC voltage mode. Turn the propane back on and the furnace breaker back on. Trigger the furnace ignition cycle (usually a wall thermostat or control panel button). Measure voltage at the igniter wire terminals while the furnace is trying to fire. If you see 0 volts or the electrode doesn’t spark, the electrode is dead. If voltage is present but no spark occurs, the control board is likely the culprit.

Step 4: Disconnect the old electrode and remove the mounting bracket

Turn off propane and power again. Carefully pull the wire connector off the control board terminals—note which wire goes where. Unbolt or unscrew the electrode mounting bracket from the furnace combustion chamber. Slide the old electrode out slowly; it may be tight or have carbon buildup around it. Set it aside and inspect the mounting hole for debris or damage before installing the new one.

Step 5: Install the new igniter electrode assembly

Slide the new electrode into the mounting bracket, aligning the ceramic or metal rod with the burner opening. Bolt or screw the bracket back in place, ensuring the electrode sits at the correct distance from the burner (usually 1/8 to 1/4 inch). Do not overtighten—you can crack the ceramic. Reconnect the wire harness to the control board terminals, matching the colors and positions from your photograph.

Step 6: Restore power and test the ignition spark

Turn the propane valve back on and flip the furnace breaker on. Trigger the ignition cycle and listen for the distinctive pop or click as the electrode fires. You should see a visible spark jumping from the electrode tip to the burner. If spark is weak or absent, turn everything off and recheck your wire connections. If connections are correct but still no spark, the control board needs replacement.

Step 7: Run a full furnace cycle and verify heat output

Set your thermostat to heat mode and let the furnace run for at least five minutes. Feel warm air coming from the vents and confirm the burner stays lit without clicking off. Check that the propane smell is absent (a sign of proper combustion). If the furnace cycles normally and produces steady heat, the electrode replacement is complete and successful.