Isotemp Spa 20 Water Heater - 5.3 gal

Offering dependable performance and ease of installation, the Isotemp Spa series of marine water heaters meets high quality marine standards - like a stainless tank, while optimzing value with a durable, non-corroding polypropylene outer case.
Versatile Spa water heaters can be installed horizontally on a shelf or platform, as well as horizontally or vertically on a bulkhead.
They are available in seven sizes – 4.0, 5.3, 6.6, 7.9, 10.6, 13 amd 16 gallons.
The Spa 15, 20 and 25 models are 12.2" in diameter and 18" to 26" long, while the Spa 30, 40, 50 and 60 models are 15.4" in diameter and 21" to 33.5" long.

Spa water heaters are specifically designed to make the best use of limited energy resources.
These marine water heaters feature corrosion and rust resistant 316 stainless steel water tanks, as well as extra thick cabinet insulation to keep hot water available at all times.
An innovative internal design places heat sources in the lowest part of the tank where the water is coldest. The domestic water inlet and outlet are specially designed to minimize the mixture of incoming cold and outgoing hot water within the unit.

Electrical Heating at the Dock —
Isotemp Spa Water Heaters are equipped with a nickel-plated copper electric heating element and an electrical thermostat set at 167°F (75°C) - hot enough to prevent bacterial growth. A thermal cut-out feature protects against overheating should the tank run dry.

Engine Heating While Underway —
These heaters also include a 316 stainless steel engine water heat exchanger coil to use engine coolant to heat the boat’s domestic water.
When underway, the domestic water in the tank reaches the same temperature as the engine water – around boiling. To prevent accidental scalding, Fisheries Isotemp Spa Water Heaters include an innovative, Temperature Control Valve (safety thermostatic mixing valve) that allows the user to regulate the temperature of the water coming out of the tank to between 100°F and 150°F (38-65°C).
This valve automatically mixes outgoing hot water with cold water from the boat’s water tanks and is easily adjustable with the turn of a knob. No tools required.
This feature also extends the capacity of onboard hot water by using only a fraction of the water in the tank to produce the desired water temperature.

• Quickly and effectively heats water via the engine or an electrical heating element if the boat is connected to shore power
• Corrugated coils for maximal engine heat exchange and faster heating – especially advantageous for sailboats
• Both heating components are located near the cold water ingress for maximum heating efficiency
• Position and design of inlet and outlet ports minimnizes the mixture of already heated water with incoming cold water
• Constructed with an acid-resistant 316 stainless steel water tank and a rustproof polypropylene cabinet
• All models sold by Fisheries Supply are supplied with a thermostatic temperature mixing valve as a safety feature to prevent scalding injuries
• Thick expanded polyurethane insulation for lowest heat loss (see image)
• 750W / 115V AC electric immersion heating element is overload protected; 230V AC option available
• Pressure relief safety valve rated at 87 psi (6 bar)
• Simple winter drain for below freezing temperatures
• Simple plug-in design with a power cable and USA plug
• Strong, stable stainless steel mounting feet can rotate 360° for platform or bulkhead installation
• Outstanding 2-year manufacturer marine warranty covers repairs and labor, while a 5-year limited warranty covers the inner tank and heat exchange coil for leakage

• Dimensions in Spec Table are overall, and include the ports and mixing valve; length is ± 0.2"
• Plumbing connections are all externally threaded 1/2" NPT; except hot water outlet at Mixing Valve is external 1/2" BSP thread
• For horizontal installations only: 1200W element option for Spa 25 & 40 models