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Raritan 20-Gallon Water Heater w/Heat Exchanger - 240V

Raritan 20-Gallon Water Heater w/Heat Exchanger - 240V

20-Gallon Water Heater with Heat Exchanger - 240V

A marine water heater is simply a small, insulated tank downstream of the pump. You must have a pressurized water system to operate a water heater. The pump draws water from the storage tank(s) and fills the water heater tank. Inside the water heater is an electrical heating element and usually a coiled tube called a heat exchanger. When AC power is available, the electrical element (controlled by a thermostat) heats the water. Away from the dock, the hot engine coolant is routed through the coiled tube to heat the water in the tank when the engine is running.

Water heaters have four threaded ports. The tank inlet connects via a tee connector to the outlet hose from the pump. A check valve is required in this line or in the heater to prevent hot water from migrating back toward the pump. The outlet connection supplies heated water to the hot side of all faucets, also using tee connectors. The other two ports are for the heat exchanger connection, which varies depending on engine installation. Use only metal fittings to plumb a water heater, never plastic. If a pressure-release valve isn’t integral, the heater will have a fifth port for this essential component.

Raritan’s 1700 Series Water Heaters are built for the long haul. A glass-lined steel tank and a rust-proof jacket keep the Raritan water heater looking great and lasting for many years. Research has shown that glass-lined steel tanks are more durable than tanks made from just stainless steel. To increase longevity and fluctuations in water quality, Raritan includes a sacrificial magnesium anode that ensures a long tank life.


  • A heat exchanger (the heat exchanger allows the user to heat water when underway by circulating engine cooling fluid through the almost 7-foot-long coil within the tank)
  • The recovery rate can be as high as 18 gallons per hour
  • High-density non-CFC foam insulation helps the tank to maintain the hot water longer, a plus if you don’t want to run the generator for hot water
  • Hot water at 160 degrees F when mixed with cold water can greatly extend the usable capacity of the tank
  • Because the heater includes an adjustable thermostat it can be set as high as 160 degrees F 
  • All plumbing connections on one side (it retrofits without difficulty to most onboard pressure systems)
  • Hot and cold-water fittings are standard 3/4 in. male NPT and the heat exchanger’s 3/4 in. female NPT


  • Tank Size: 20-gallon
  • Volts: 240


  • Simple installation – retrofits to most on-board pressure systems
  • Proven long-life design
  • Withstands the rigors of the marine environment
  • The glass-lined steel tank is more durable than stainless steel
  • The attractive polymer jacket resists corrosion from dampness
  • Ignition-protected, adjustable thermostat
  • Round tanks are designed to withstand more pressure than square tanks
  • Glass-lined steel tank for long life and high efficiency
  • Environmentally friendly CFC-free foam insulation
  • Replaceable magnesium anode to protect the tank and neutralize acids in the water
  • The tank is covered by a five-year Limited Warranty
  • Each unit is assembled by hand, individually tested, and backed by Raritan’s two-year Limited Warranty and legendary technical support team

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