Isotemp SPA marine water heater with heat exchanger in the SPA50 model delivers hot water to the boat's pressurized water system. The tank has a 50 L capacity and can heat the water using the built-in 220 V/750 W heating element or indirectly via the engine's fresh water cooling circuit and the internal heat exchanger coil.
The inner tank and the corrugated heat exchanger coil are manufactured from AISI 316 stainless steel. The electric heating element is made of nickel-plated copper, while the grey outer casing is made of polypropylene. CFC-free polyurethane foam around the tank reduces heat loss, and the included mounting brackets are made of AISI 304 stainless steel.
The SPA50 measures 745 mm in total length and Ø392 mm across the casing. The total width across the mounting feet is 390 mm, and the distance between the brackets lengthwise is 430 mm. The marine water heater can be mounted horizontally or vertically on a shelf or bulkhead capable of supporting the weight of the full tank. Approximately 30 cm of clearance should be provided in front of the unit for service.
The connections for cold water, hot water, and engine water in and out have 1/2" NPT male threads. When connecting to the engine's cooling circuit, a hose of at least 16 mm must be used, and the cooling water flow through the heat exchanger must be at least 2 L/min. Engine water hoses must be heat-resistant to at least 100 °C and pressure-rated to 6 bar. Fresh water hoses must be food-grade, heat-resistant, and pressure-rated to 8 bar.
The safety valve is set to 6 bar, while the variant-specific indication for max pressure is 15 bar. The maximum working pressure from the fresh water pump is 3.8 bar. The operating thermostat is set to 75 °C, and a dual, manually resettable over-temperature protection cuts off at 96 °C. The thermostatic mixing valve with item no. 50.189.58 is not included and must be purchased separately if the tap temperature needs to be regulated.
The internal electrical connections are factory-fitted. The heating element must only be energized when the tank is completely filled with water. Connection must be made to a properly grounded installation with a residual current device (RCD). In case of risk of frost, the tank must be completely emptied; on raw water-cooled engine installations, the heat exchanger coil must also be drained. The safety valve must be activated regularly to check for free movement and remove any limescale deposits.
The water heater is CE marked and complies with 2014/35/EU and 2014/30/EU. The inner tank is covered by a 5-year limited warranty, while the product has a 2-year manufacturer's warranty against material and production defects. As a heat-resistant connection at the hot water outlet, the 45 cm long, metal-braided hose with item no. 50.289.56 can be used.
Key features50 L marine water heater with internal heat exchanger coil
Heating via 220 V/750 W heating element or engine cooling water
Inner tank and corrugated coil in AISI 316 stainless steel
CFC-free polyurethane insulation and grey polypropylene casing
Product dimensions: 745 × Ø392 mm
Horizontal or vertical mounting with AISI 304 brackets
1/2" NPT male water and engine connections
Safety valve set to 6 bar
Operating thermostat at 75 °C and over-temperature protection at 96 °C
Thermostatic mixing valve purchased separately
