The Suburban Nautilus IW60 and IW60RL are different on-demand RV water-heater configurations. Both use a combustion-air and water-flow control system, but their ignition modules are numbered separately. The IW60RL also has a model-specific internal pump, tubing and temperature-probe kit. Check the heater nameplate before choosing a board, valve or water-side component.
Parts pictured in this guide
Select an image for product details, or jump to the parts list. Match the complete model and part number before ordering.
Factory part numbers and model differences
| Suburban part | Service part or assembly | Application / distinction |
|---|---|---|
| 5581A | IW60 complete on-demand water heater | IW60 model |
| 5280A | IW60RL complete on-demand water heater | IW60RL model |
| 521135 | Ignition control module | IW60 |
| 521212 | Ignition control module | IW60RL |
| 521299 | Internal pump, tube and temperature-probe service kit | IW60RL in current parts catalog |
| 161248 | Nautilus gas-control valve | Verify installed valve configuration |
| 233229 | Combustion-air pressure switch | Nautilus service component |
| 233231 | Overheat sensor | Nautilus safety sensing component |
| 233237 | Water-flow sensor | Nautilus flow detection |
| 233245 | Ignition electrode and flame-sensing probe | Nautilus ignition service part |
| 521136 | Blower control module | Separate from main ignition board |
| 391127 | Blower assembly | Motor and blower system |
| 161249 | Two-stage regulator | Separate from gas-control valve 161248 |
| 233307 | Freeze-protection valve | Verify heater generation and original valve |
| 233253 | Resettable limit switch | Match exact heater version |
| 161291 | White wall control centre | Verify wall interface and connector |
| 161292 | Black wall control centre | Verify wall interface and connector |
Which internal parts differ?
| System position | Part-identification rule |
|---|---|
| Main electronic module | IW60 uses board 521135; IW60RL uses board 521212. A visually similar board isn't proof of compatibility. |
| Internal water-side pump | Suburban's 2026 parts manual lists 521299 as an IW60RL internal pump/tube/probe kit. It is not identified there as a universal IW60 part. |
| Combustion-air sensing | The 233229 air-pressure switch is separate from the 233237 water-flow sensor. |
| Ignition and temperature protection | The 233245 electrode/probe, 233231 overheat sensor, 233253 limit and 233307 freeze valve each serve different functions. |
| Gas system | The 161248 gas valve and 161249 regulator are separate components; preserve the original pressure and gas installation arrangement. |
| Control options | 161291 (white) and 161292 (black) are listed on-demand control centres; confirm the original connector and heater model. |
Original manufacturer illustration
Suburban factory replacement-parts drawings, including the Nautilus blower and flow sensor. Use the full factory manual for the model-specific connection and service procedures.
Open the original manufacturer's PDF to inspect small part positions and labels.
Before choosing or replacing a component
Original manufacturer reference documents
Suburban May 2026 parts manual, Nautilus parts on pages 12–14Suburban original IW60/IW60RL operation and maintenance instructionsOther RV parts-reference pages
View the matching products
Choose a photograph to open the corresponding NewRVParts listing. Exact model and manufacturer numbers help distinguish parts that can look similar.
5581A — Suburban Nautilus IW60 complete heaterIW60 system; confirm model plate before parts selection
5280A — Suburban Nautilus IW60RL complete heaterIW60RL recirculating-loop version
521135 — Suburban IW60 ignition control moduleIW60 board, not the IW60RL circuit board
521212 — Suburban IW60RL ignition control moduleIW60RL board; match the installed serial/model
233237 — Suburban Nautilus water-flow sensorDemand water-flow sensing
161248 — Suburban Nautilus gas valveGas-control valve, separate from the regulator
521299 — Suburban IW60RL internal pump/tube/probe kitCurrent factory parts catalog specifies this as IW60RL kit
233229 — Suburban Nautilus air-pressure switchCombustion-air proof switch