The Suburban Mfg 5581A (IW60 / Nautilus) is a continuous-flow, tankless LP gas water heater engineered specifically for recreational vehicles. Also referenced under part numbers 5186A and 5286A, this on-demand unit eliminates the storage tank entirely — delivering an unlimited supply of hot water the instant a fixture is opened, with no waiting for tank recovery.
Powered by a self-modulating, microprocessor-controlled combustion system, the IW60 automatically adjusts its output between 15,000 and 60,000 BTU/h to match demand, conserving propane while maintaining precise water temperatures. The digital control interface allows easy adjustment across an adjustable range of 95°F to 130°F. A built-in stainless steel heat exchanger ensures durable, corrosion-resistant performance over the long term.
Key Features:
- Tankless On-Demand Design: Provides continuous hot water without tank storage or reheat wait times
- Self-Modulating Output: Automatically adjusts between 15,000–60,000 BTU/h for efficiency and precise temperature control
- Adjustable Temperature Range: Digital interface allows selection from 95°F to 130°F
- Stainless Steel Heat Exchanger: Built for long-lasting, corrosion-resistant performance
- Built-In Freeze Protection: Includes both powered and non-powered freeze protection for cold-climate operation
- LP Gas Operation: Compatible with standard propane (LP) fuel systems
- Includes DC Converter: Allows operation from the RV's DC power system
- 2-Stage Modulating Combustion System (MCS): Monitors and adjusts combustion for efficiency and safety
- Compact Footprint: 12.5" H × 12.5" W × 20" D for straightforward installation in standard RV bays
Also known as: Suburban IW60, Suburban Advantage On Demand Water Heater, Suburban Nautilus IW60. Cross-reference part numbers: 5186A, 5286A, 5581A, IW60. Supersedes part number 620015.
Note: On Demand Control Center, wall vent, and water heater access door are sold separately.
