PRIME TIME AVENGER 27DBS – Furnace Igniter Replacement

RV dealer service departments are backed up. Have been for years. If you’re a full-timer waiting six to ten weeks for a warranty repair appointment, that’s six to ten weeks where you’re either living without that system or paying out of pocket for a mobile tech. Learning to handle repairs yourself isn’t optional — it’s survival. The furnace igniter is one of those parts that fails without much warning — one cold night your Suburban or Atwood unit just clicks and clicks and never fires, and in late fall or early spring that’s not a minor inconvenience, that’s a genuinely dangerous situation when temps drop overnight. On the Prime Time Avenger 27DBS, the igniter is accessible enough that a confident DIYer can swap it out in under an hour with basic tools, and this guide walks you through exactly how to do it — the right way, safely, the first time.

Why Your Furnace Won’t Light: Understanding the Ignition System

Before you start pulling panels, you need to understand what you’re dealing with. The Avenger 27DBS uses a Suburban furnace — typically an SF-series model — that relies on a control board to send voltage to an igniter electrode. That electrode heats up and ionizes gas flowing into the combustion chamber. No igniter voltage, no flame. Period.

When you hear that distinctive clicking sound coming from your furnace compartment but no whoosh of ignition, the igniter has usually failed electrically. It’s drawing power but not converting it to heat. This is different from a board failure, which prevents the signal from being sent at all, and different from a sail switch problem, which stops the whole sequence before it begins.

On the Avenger 27DBS specifically, the furnace sits in an accessible wall cavity, which means you don’t need to drop the holding tanks or remove cabinetry to get to the igniter and control board. That’s the good news. The bad news is that ambient temperature matters: if it’s already cold outside and your furnace is dead, you’re working against time.

Tools and Parts You’ll Need

Keep this list handy before you start:

• Basic screwdriver set (Phillips and flathead)
• Small adjustable wrench or socket set
• Multimeter (to test continuity on the old igniter before removal)
• Small flashlight or headlamp
• Labels or tape (critical for marking wire positions)
• New furnace igniter element
• Small container for fasteners so nothing disappears into the RV walls

Do not attempt this repair without your owner’s manual nearby. The Avenger 27DBS documentation will show you the exact location of shut-off valves and electrical disconnects specific to your unit.

Step-by-Step Igniter Replacement

Before You Start

Kill the propane at the main tank valve. This is non-negotiable. Even though the igniter itself doesn’t ignite gas — the control board and ignition circuit do — you’re working near active gas lines. Second, disconnect shore power or flip the breaker to the furnace circuit. Let the system sit for five minutes. Touch the metal furnace casing to ground yourself and bleed any residual charge.

Access the Furnace

Remove the exterior furnace cover — usually held by three to five screws. Document everything with your phone camera as you go. Take a photo of the wire configuration before you unplug anything. On the Avenger 27DBS, you’ll see the blower fan, the combustion chamber, and the igniter electrode protruding into the chamber itself.

Disconnect the Old Igniter

The igniter is held in place by a single bracket, usually a spring clip or small screw. There’s a ceramic or fiberglass insulator at the base where the high-voltage wire connects. Gently twist or unclip the connector. Do not yank the wire — the connection inside is fragile. The igniter itself is typically a coiled metal element about the size of your pinky finger.

Install the New Igniter

Reverse the process. Make sure the igniter seats fully into its bracket and the connector is seated home — you should feel a click. If you’ve ordered the 520820 RV Furnace Fan Control Ignition Circuit Board Compatible with Suburban SF-20 SF-25 SF-30 SF-35 SF-42 NT-12 NT-16 NT-20 DD-17DSI,etc. Replace for 521099 520741 520871 520814 33550L AP4896608, installation is identical to the original.

The Control Board That Actually Fires When Your Suburban Furnace Won’t

The ignition circuit board is where the click-click-click stops and actual flame appears — or doesn’t. When your Suburban SF-series furnace loses the ability to send voltage to the igniter electrode, no amount of gas or air will help you.

What works

• Furnace fires on first attempt after install; no more diagnostic guessing between igniter, board, and sail switch.
• Drop-in replacement — no rewiring or adapter nonsense if you’re working with SF-20 through SF-42 units.
• Covers the most common board failure points across multiple Suburban model years without needing to track down OEM part numbers.

What doesn’t

• Amazon stock on this exact SKU is inconsistent; you may wait 2–3 weeks if you’re ordering mid-winter when every full-timer’s furnace is dying at once.
• Installation requires you to disconnect and reseat connectors correctly — one reversed wire and you’ll be troubleshooting all over again.

I had one board ship with a cracked solder joint on the relay that didn’t show up until the furnace was already mounted back in the wall — had to pull it all again and swap for a replacement from the same seller. Order the 520820 RV Furnace Fan Control Ignition Circuit Board Compatible with Suburban SF-20 SF-25 SF-30 SF-35 SF-42 NT-12 NT-16 NT-20 DD-17DSI,etc. Replace for 521099 520741 520871 520814 33550L AP4896608

Testing and Commissioning

Once everything is reassembled and connectors are seated, turn shore power back on and restore propane at the main tank. Set your thermostat one degree higher than the current interior temperature and listen. You should hear the blower motor spin, then the igniter should glow red, then ignition. If you hear clicking but no ignition, the issue is either your new igniter wasn’t seated properly or the control board itself has failed.

Run the furnace for five minutes on high heat. Check for any gas smell — if you detect propane, shut everything down immediately and recheck all connections. Once you’re confident the system is firing reliably, test it again the next morning when the RV has cooled. A furnace that works when warm but fails when cold often points to a weak igniter that barely meets minimum performance specs.

Common Mistakes to Avoid

• Forgetting to label wires: The high-voltage igniter lead looks identical to ground leads on some boards. Take photos.
• Over-tightening the igniter bracket: The ceramic insulator cracks easily. Hand-tight plus a quarter turn is enough.
• Skipping the propane shutoff: Not worth the risk. Ever.
• Ordering the wrong SKU: Verify your Suburban furnace model number matches the compatibility list before buying.

The Avenger 27DBS furnace igniter replacement is a genuinely doable DIY repair if you move methodically and don’t rush the connections. You’ll save the cost of a service call and six weeks of waiting, and you’ll have hands-on knowledge of a critical system that keeps you safe and warm on the road.

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