521099 Suburban Ignition Control Module Board 12VDC Furnaces

The Suburban 521099 Ignition Control Module Board is the OEM 12‑volt control board used in Suburban RV furnaces and select water heaters. This third‑generation (3G) DSI board manages the full ignition sequence, blower operation, flame sensing, safety lockout, and post‑purge cycles.

Designed for reliability in RV, mobile‑home, and trailer heating systems, the 521099 includes integrated fan control, making it the correct replacement for nearly all Suburban SF and NT series furnaces manufactured from 2001 to present.

This board features a 3‑try ignition sequence, automatically attempting ignition three times before entering safety lockout. It is compatible with all Suburban 12V furnaces and water heater model 520820.

Key Features

• OEM Suburban 12V DC ignition control module

• 3‑try ignition sequence with safety lockout

• Integrated fan control (blower start, pre‑purge, post‑purge)

• Flame rectification sensing

• Pre‑purge cycle (~15 seconds)

• Post‑lockout fan run (~3 minutes)

• Universal fit for all Suburban SF & NT series furnaces (2001–current)

• Works with Suburban water heater model 520820

• Will NOT replace 24‑volt AC boards

Dimensions

• 6.5" × 0.5" × 2.6" (OEM spec)

Cross‑Reference Part Numbers

• 520820 — direct OEM replacement

• 520741 — older Suburban board replaced by 521099

• 232613 — listed replacement 

• 520871 / 520814 / 520820 — aftermarket equivalents 

Replaces 520741

Suburban replacement parts local flame sense 12 volt dc.

Replaces S520820, S521099, S521099, 520741