Atwood AFSD20121 — small-vent, less-door. This AFSD20 variant uses a low-profile small-vent arrangement rather than the conventional exterior door. The diagram identifies the original grille, blower, burner, manifold and control references while keeping optional vent revisions separate.
AFSD20 input rating: 18,000 BTU/hr according to Atwood's AFS technical data. Check the complete furnace identification plate and serial number. The original component references below do not confirm interchangeability across vent and gas-fitting configurations.
AFSD20121 numbered exploded furnace parts
| Reference | Manufacturer part number | Quantity | Historical description |
|---|---|---|---|
| 1 | 30322 | 1 | CIRCUIT BREAKER, 7 AMP |
| 3 | 30260 | 1 | FRONT GRILL KIT, LESS DOOR |
| 6 | 36688 | 1 | DUCT ADAPTER 2 INCH |
| 7 | 31474 | 1 | DUCT ADAPTER 4 INCH |
| 8 | 31361 | 1 | DUCT COVER PLATE, 4 INCH |
| 9 | 35100 | 1 | ELECTRODE ASM. SMALL |
| 10 | 35711 | 1 | HEAT EXCHANGER, SMALL |
| 11 | 31244 | 1 | CASING LEG |
| 12 | 35706 | 1 | GAS LINE GROMMET |
| 13 | 30197 | 1 | VENT COVER PANEL SM V2-W |
| 13 | 30456 | 1 | VENT PANEL EXTENSION SML V3 |
| 14 | 31501 | 1 | ELECTRONIC IGNITION BOARD |
| 14 | 32353 | 1 | UNIVERSAL IGNITION DC SMT — verify model and service revision |
| 15 | 35712 | 1 | MANIFOLD EXT ASM KIT, SML — verify model and service revision |
| 16 | 30760 | 1 | MOTOR, S20 — verify model and service revision |
| 17 | 30789 | 1 | ORIFICE 1.25MM LP |
| 18 | 31091 | 1 | LIMIT SWITCH, 190 DEGREE |
| 19 | 31093 | 1 | SAIL SWITCH, SMALL-WHITE - Serial# 724xxxxx and Lower — verify model and service revision |
| 19 | 33063 | 1 | SAIL SWITCH DF-BLACK - NLA - Serial# 724xxxxx and Higher — obsolete; confirm serial |
| 20 | 32300 | 1 | THERMOSTAT, HEAT ONLY, BLACK |
| 20 | 38452 | 1 | T-STAT HEAT ONLY - BROWN |
| 20 | 38453 | 1 | THERMOSTAT HEAT ONLY- WHITE |
| 21 | 31098 | 1 | VALVE 12VDC TOP SMALL — verify model and service revision |
| 21 | 31096 | 1 | VALVE KIT, 12VDC -V1 SML |
| 22 | 30268 | 1 | BURNER HEAD, LP GAS |
| 25 | 30580 | 1 | VENT KIT, LD .750 V3 |
| 25 | 31266 | 1 | VENT KIT, LD .750 V4 |
| 27 | 30936 | 1 | VENT KIT, LD .750 V4 SW |
| 28 | 30611 | 1 | VENT PANEL EXTENSION SML V4 |
| 29 | 31113 | 1 | BLOWER WHEEL, SMALL |
| 30 | 33128 | 1 | COMBUSTION AIR WHEEL |
| 33 | 30457 | 1 | VENT PANEL EXTENSION SML V3 |
| 34 | 31114 | 1 | WIRING HARNESS, DC |
| NS | 31923 | 1 | VENT PANEL EXTENSION SM V1 |
| NS | 32349 | 1 | MANIFOLD, INLET SMALL — manifold inlet, not illustrated |
Replacement parts pictured at NewRVParts
These product listings match manufacturer numbers linked in the parts diagram. Confirm the exact furnace model, serial range and component version before ordering. Current availability appears on the product listing.
Diagram ref 6 · MPN 36688
Dometic 36688 Atwood 2-Inch RV Furnace Duct Adapter
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Diagram ref 7 · MPN 31474
Atwood 31474 Aluminum 4-Inch RV Furnace Duct Collar
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Diagram ref 8 · MPN 31361
Dometic 31361 4-Inch RV Furnace Duct Knockout Cover Plate
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Diagram ref 14 · MPN 31501
Atwood 31501 12V DSI Furnace Ignition Board With Fan Control
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Diagram ref 18 · MPN 31091
Atwood 31091 190°F RV Furnace High-Limit Safety Switch
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Diagram ref 20 · MPN 32300
Dometic 32300 Black 12V Heat-Only RV Furnace Thermostat
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Diagram ref 20 · MPN 38453
Dometic 38453 White HFH-2000 RV Furnace Thermostat
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Diagram ref 22 · MPN 30268
Atwood 30268 LP-Gas Furnace Burner Head
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Diagram ref 30 · MPN 33128
Dometic 33128 Atwood RV Furnace Combustion Wheel Kit
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Diagram ref 34 · MPN 31114
Dometic 31114 DC Wiring Harness for Atwood AFMD Furnaces
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