Tiffin Open Road Allegro – Furnace Igniter & Control Board Replacement

Living full-time in an RV changes your math on repairs fast. You start calculating the cost of parts versus the cost of a mobile tech, and you realize that most of these jobs — once you understand the system — are absolutely within reach for someone who’s willing to read a guide, watch a video, and take their time. The furnace in a Tiffin Open Road Allegro is one of those repairs that sounds intimidating until you actually get into it — a failed igniter or a dead control board will leave you cold-camping in conditions that are anything but fun, and a mobile tech call for something like this can run several hundred dollars before they even touch the unit. What I’ve put together here is based on actually doing this repair, understanding how the Suburban or Atwood furnace system in these rigs cycles — from the thermostat call, through the sail switch, to the igniter firing sequence — so you’re not just following steps blindly, you’re understanding why each step matters. If your furnace is clicking without igniting, blowing cold air, or not responding at all, this guide will walk you through diagnosing whether it’s the igniter or the control board that’s the real culprit, and how to replace whichever one it turns out to be.

The Igniter That Actually Survives a Full Season in a Tiffin Allegro

The igniter electrode is the first thing to fail in a Suburban SF-35 furnace, and it’s the part that decides whether you’re warm or shivering at 2 AM in November. A failed igniter won’t spark, the control board won’t see flame, and your furnace shuts down on every cycle — or won’t light at all.

What works

• Direct OEM-spec replacement for SF-series furnaces — drops into the same mounting bracket without rewiring or adapters.
• The probe geometry is precise enough that it lights on first attempt after install, no fiddling with gap or electrode position.
• The wire harness connector matches the control board pins perfectly, so you’re not chasing intermittent ignition failures three weeks after the repair.

What doesn’t

• Amazon third-party seller quality is wildly inconsistent — some batches arrive with cracks in the ceramic or corroded connector pins, so inspect it immediately and test continuity before you install.
• If you have an older Allegro (pre-2010) with a different control board revision, this part may not seat correctly without minor bracket bending — verify your model year and board number first.

I second-guessed the part choice the first time I installed one because the connector felt slightly loose compared to the OEM part, but that turned out to be normal wear on the board side, not the new electrode. 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)

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