Suburban ST42 Tankless RV Water Heater 5381A

The Suburban ST42 Tankless RV Water Heater is a 42,000 BTU on-demand propane water heater designed to provide continuous hot water without the limitations of a traditional storage tank. The burner only operates when hot water is requested, helping reduce unnecessary propane use while delivering consistent outlet temperatures throughout the RV.

The ST42 is designed to fit many standard 6-gallon RV water heater openings and comes ready for installation with an included wall-mounted digital control center. This unit does NOT include the outside access door.

Suburban Model: ST42
Suburban Part Number / SKU: 5381A/ 5481A/ 5391A
BTU Rating: 42,000 BTU/h
Type: Tankless / On-Demand RV Water Heater
Fuel: LP Gas

Suburban ST42 Features

• Continuous on-demand hot water

• 42,000 BTU/h propane burner

• Included wall-mounted digital control center

• Maximum water temperature up to 131°F

• Flame-out protection

• High-temperature scald protection

• Automatic fan monitoring

• Active freeze protection when power and propane are available

• Pressure relief safety valve

• Low, high, and overcurrent voltage protection

• Two-year limited warranty

Designed for Standard RV Water Heater Openings

The Suburban ST42 is sized to fit into many existing standard 6-gallon RV water heater sidewall cutouts, making it a strong option when replacing an older tank-style or tankless RV water heater.

Approximate water heater dimensions:

• Height: 13-1/8"

• Width: 13-1/8"

• Depth: 13"

The exterior access door is sold separately here.

ST42 vs. ST60

The ST42 provides 42,000 BTU/h and is best suited to applications where incoming water temperatures are relatively warm. Suburban states that the ST42 can provide continuous water up to approximately 120°F when incoming water is at least 70°F at a 1.5 GPM flow rate.

For colder climates, winter RV use, or situations where incoming water temperatures regularly fall below 70°F, Suburban recommends the higher-output ST60 60,000 BTU tankless water heater.

Why Choose a Suburban ST42 Tankless Water Heater?

The ST42 eliminates the need to wait for a storage tank to reheat between showers or other hot-water demands. Its compact design, digital temperature control, and built-in protection systems make it a practical replacement or upgrade for RV owners who want continuous hot water without moving to a larger-capacity tank heater.

Suburban ST42 part number 5381A is a 42,000 BTU tankless RV water heater designed for continuous hot water and includes a wall-mounted digital control center.