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Suburban 520820 / 521099 12V DC RV Furnace Fan Control & DSI Ignition Circuit Board (NT / SF / DD Series) Engineering Diagram
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SPECFOUNDRY SKU: SF-RV-104 · BRAND REF: Suburban / Airxcel

Suburban 520820 / 521099 12V DC RV Furnace Fan Control & DSI Ignition Circuit Board (NT / SF / DD Series)

Stamped Casting / OEM Numbers: 520820 521099 520871 520814 232261 SUB-520820

Compatible Units: Suburban NT-12, NT-16, NT-20, NT-24, NT-30, NT-34, SF-20, SF-25, SF-30, SF-35, SF-42 & DD-17DSI 12V DC RV Furnaces

Critical Dimensions & Spec: 4.25" x 3.25" conformal-coated 12V DC DSI ignition module; 15-second pre-purge; 3-try lock-out safety logic

$104.99
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Pre-Order Dimensional Verification Checklist

OEM Cross-Reference & Stamped Casting Number Table

Use this cross-reference table to confirm that the number stamped or printed on your original hardware or circuit board corresponds to SpecFoundry SKU SF-RV-104:

Stamped / OEM Part Number Manufacturer / System Brand Compatible Models & Years SpecFoundry Replacement SKU
520820Suburban / AirxcelSuburban NT-12, NT-16, NT-20, NT-24, NT-30, NT-34, SF-20, SF-25, SF-30, SF-35, SF-42 & DD-17DSI 12V DC RV FurnacesDirect Match (SF-RV-104)
521099Suburban / AirxcelSuburban NT-12, NT-16, NT-20, NT-24, NT-30, NT-34, SF-20, SF-25, SF-30, SF-35, SF-42 & DD-17DSI 12V DC RV FurnacesDirect Match (SF-RV-104)
520871Suburban / AirxcelSuburban NT-12, NT-16, NT-20, NT-24, NT-30, NT-34, SF-20, SF-25, SF-30, SF-35, SF-42 & DD-17DSI 12V DC RV FurnacesDirect Match (SF-RV-104)
520814Suburban / AirxcelSuburban NT-12, NT-16, NT-20, NT-24, NT-30, NT-34, SF-20, SF-25, SF-30, SF-35, SF-42 & DD-17DSI 12V DC RV FurnacesDirect Match (SF-RV-104)
232261Suburban / AirxcelSuburban NT-12, NT-16, NT-20, NT-24, NT-30, NT-34, SF-20, SF-25, SF-30, SF-35, SF-42 & DD-17DSI 12V DC RV FurnacesDirect Match (SF-RV-104)
SUB-520820Suburban / AirxcelSuburban NT-12, NT-16, NT-20, NT-24, NT-30, NT-34, SF-20, SF-25, SF-30, SF-35, SF-42 & DD-17DSI 12V DC RV FurnacesDirect Match (SF-RV-104)

Common Failure Symptoms Solved by SF-RV-104

Technicians and property owners typically replace 520820 when experiencing one or more of the following failure modes:

  • Suburban furnace blower fan runs continuously but ignitor never sparks or opens gas valve
  • Furnace ignites for 3 seconds then shuts down because flame sense circuit failed
  • Corroded 6-pin Molex plug on legacy 520814 / 520820 board

Step-by-Step Dimensional Verification & Installation Notes

Verify 12.2V+ DC at furnace power lead and test sail switch continuity (232261) first. Unplug edge harness and high-voltage spark lead, swap 520820 / 521099 board into plastic standoff tray.

Related Technical Guide: Dometic, Norcold, Atwood & Suburban RV Circuit Board & Alde 3010/3020 Cross-Reference Guide →

Frequently Asked Technical Questions (520820)

Where is the casting or OEM part number (520820 / 521099 / 520871) stamped on this part?

On Suburban / Airxcel assemblies, look for the stamped or die-cast numbers (520820, 521099, 520871, 520814, 232261, SUB-520820) on the underside of the metal housing, along the link arm, on the stainless hinge track, or printed on the circuit board/valve label. Note that casting numbers identify the housing casting, so always confirm critical dimensions (4.25" x 3.25" conformal-coated 12V DC DSI ignition module; 15-second pre-purge; 3-try lock-out safety logic) as well.

Does SpecFoundry SKU SF-RV-104 directly replace OEM part 520820 (520820, 521099, 520871, 520814, 232261, SUB-520820)?

Yes. SF-RV-104 is verified to match the mounting footprint, electrical/mechanical ratings, and dimensional envelope of Suburban / Airxcel 520820, 521099, 520871, 520814, 232261, SUB-520820 used on Suburban NT-12, NT-16, NT-20, NT-24, NT-30, NT-34, SF-20, SF-25, SF-30, SF-35, SF-42 & DD-17DSI 12V DC RV Furnaces.

What measurements should I verify before ordering SF-RV-104?

Before ordering, verify: (1) Stamped or OEM code matches one of 520820, 521099, 520871, 520814, 232261, SUB-520820; (2) Dimensional spec matches: 4.25" x 3.25" conformal-coated 12V DC DSI ignition module; 15-second pre-purge; 3-try lock-out safety logic; and (3) Application matches: Suburban NT-12, NT-16, NT-20, NT-24, NT-30, NT-34, SF-20, SF-25, SF-30, SF-35, SF-42 & DD-17DSI 12V DC RV Furnaces.

How fast does SF-RV-104 ship and what payment methods are accepted?

SF-RV-104 ships within 1–2 business days from our US warehouse network. Flat-rate US Ground shipping is $8.95, or FREE on orders of $150+. You can check out online immediately via PayPal, Venmo, Credit/Debit Card, or request an Instant Card Payment Link / Net-30 Commercial PO Invoice.

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