Raritan — Water Heater 20 Gal with Heat Exchanger 120V — 78-172011
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The Raritan 1700 Series 20-Gallon Marine Water Heater is a heavy-duty onboard hot water tank for marine galleys, showers, and domestic water systems. Model 172011 / 78-172011 combines a 120V AC electric heating element with an internal engine heat exchanger, allowing the unit to heat water from shore power, generator power, or engine coolant circulation while underway. Its 20-gallon capacity makes it suitable for larger cruising boats, trawlers, and liveaboard-style marine installations where dependable hot water storage is required.
Key Features
- Product code: 78-172011
- Raritan model number: 172011
- Series: Raritan 1700 Series
- Tank capacity: 20 gallons / 75.7 litres
- Electrical system: 120V AC
- Heating element: 1250 watts / approximately 10 amps
- Heat exchanger: Internal wrap-around engine heat exchanger coil
- Heat exchanger coil length: Over 7 feet
- Dimensions: 24.25" high x 18.75" outer diameter
- Mounting note: 1" mounting flange adds approximately 2" to total base diameter
- Tank construction: Porcelain glass-lined steel tank
- Insulation: Dense CFC-free foam insulation
- Exterior jacket: White high-impact non-corrosive polymer casing
- Thermostat range: Adjustable from 110°F to 160°F
- Factory thermostat setting: 120°F
- High-limit safety cutout: 190°F
- Freshwater fittings: 3/4" male NPT
- Heat exchanger fittings: 3/4" female NPT
- Working pressure rating: 150 PSI
- Relief valve: 75 PSI temperature and pressure relief valve
Product Compatibility
This water heater is intended for marine domestic hot water systems requiring a 20-gallon tank, 120V AC electrical heating, and engine-coolant heat exchanger capability. It is suited for onboard plumbing systems supplying hot water to sinks, galleys, washdowns, and showers where the installation space, voltage, plumbing fittings, and engine coolant loop are compatible.
The integrated heat exchanger allows engine coolant to warm the water tank while the engine is running, reducing the need to rely only on the electric element when underway.
Fitment Notice
Confirm available installation space, voltage, breaker capacity, plumbing layout, engine heat exchanger routing, and service access before ordering. This model uses a front-service connection layout, with potable water and heat exchanger connections placed on the same side for easier retrofit work.
Measure both the tank body and the mounting footprint. The main tank diameter is approximately 18.75", but the mounting flange increases the base diameter by approximately 2".
When This Product Needs Replacement
Replace the water heater if the tank leaks, the jacket or fittings show significant corrosion damage, the electric element no longer heats properly, the thermostat or high-limit safety controls fail, or the heat exchanger coil no longer transfers heat effectively from the engine coolant circuit. Replacement may also be needed when upgrading capacity, converting voltage, refitting the domestic plumbing system, or replacing an aging tank with poor heat retention.
Common service signs include rusty discharge, water around the tank base, frequent relief-valve discharge, slow recovery time, no hot water on electric heat, no hot water while underway, or visible damage to plumbing and heat exchanger fittings.
Installation Notes
Install in a dry, accessible location with proper mounting support for the filled tank weight. Confirm that the 120V AC circuit is correctly protected and installed according to marine electrical standards. Freshwater plumbing should be pressure-rated and compatible with hot water service.
When connecting the engine heat exchanger, verify coolant hose routing, flow direction, hose size, clamps, isolation valves, and engine manufacturer requirements. Do not connect the heat exchanger in a way that restricts engine cooling flow. The temperature and pressure relief valve must remain installed, unobstructed, and routed safely.
Follow the Raritan installation manual for wiring, plumbing, thermostat adjustment, relief valve installation, winterization, and commissioning.
Alternate/Superseded Part Numbers
- Raritan model number: 172011
- Distributor product code: 78-172011
- Common description: Raritan 1700 Series 20-Gallon 120V Marine Water Heater with Heat Exchanger
Parts Desk Insight
The key buying checks for this water heater are capacity, voltage, heat exchanger requirement, and installation footprint. A 20-gallon marine water heater is much heavier when full and needs proper support, safe wiring, and enough clearance for the front-side plumbing connections. Confirm the boat’s available space and electrical system before ordering.
Shipping: Ships same or next day for fast Canada wide shipping. ⚓
Shipping information
In-stock and OEM parts: ship same or next business day.
Locally warehoused items: ship within 3–4 business days.
Special-order items: timeline confirmed after order.
Returns & warranty
Returns & Satisfaction Guarantee
We stand firmly behind the quality of every product we sell. Your confidence matters to us — and we back it with a straightforward 30-Day Satisfaction Guarantee.
If you are not fully satisfied, you may request a return within 30 days of delivery. All returns must receive pre-approval prior to being sent back. Unauthorized returns will not be accepted.
To qualify for a return:
Item must be in new, unused condition
Product must be in its original packaging
All parts, components, hardware, manuals, and accessories must be included
Packaging must be undamaged and suitable for resale
Important:
Electronics are strictly inspected. No returns on open-box electronics. Exceptions may apply only with prior written approval. Any electronic unit that has been installed, powered, activated, or altered may not be eligible for return.
We are serious about product integrity — and equally serious about taking care of our customers. If there is ever a product issue, contact us immediately so we can make it right.
For return authorization, please contact our support team before shipping anything back.