Coates Electric Pool Heater, 18kw 240V Single Phase, Salt Water Application

The Coates 18kW 240V Single-Phase Electric Pool & Spa Heater for Salt Water Applications (Model 12418CES / 12418CPHS — with the "S" saltwater/corrosion-resistant package) is a heavy-duty inline immersion water heater designed for high-occupancy commercial spas, athletic recovery tanks, and resort plunge pools utilizing electrolytic salt chlorine generators (typically 2,500 to 4,500+ ppm TDS/NaCl).

At 18kW on a single-phase 240V supply, the unit operates at a continuous load of 75 Amps. The saltwater package provides critical metallurgy and tank barrier enhancements to prevent chloride-induced stress corrosion cracking, premature heating element burnout, and electrolytic tank failure.

Electrical & Heating Performance

• Model Designation: Coates 12418CES / 12418CPHS series (124 designates 1-Phase 240V; suffix designates Saltwater/Titanium package).

• Heating Capacity: 18 kW (18,000 Watts).

• Thermal Output: 61,418 BTU/hr ($18\text{ kW} \times 3,412.142\text{ BTU/kWh}$).

• Operating Voltage: 240V AC, Single-Phase (1Ø), 2-wire plus ground, 60 Hz.

• Full Load Amperage (FLA): 75.0 Amps

  $$\text{FLA} = \frac{18,000\text{ W}}{240\text{ V}} = 75.0\text{ A}$$

• Overcurrent Protection (Breaker Sizing): Requires a dedicated 2-pole 100-Amp circuit breaker conforming to NEC 125% continuous-duty loading standards ($75.0\text{ A} \times 1.25 = 93.75\text{ A}$ minimum branch rating, standardizing on a 100A 2-pole breaker).

• Conductor Sizing: Minimum #3 AWG or #2 AWG THHN/THWN copper conductor (rated 75°C/90°C terminals, adjusted for conduit run length, ambient derating, and raceway fill).

Salt Water Construction & Metallurgy Upgrades

• Titanium / Incoloy 825 Sheathed Elements: Immersion elements are upgraded from standard alloys to Titanium or high-molybdenum/nickel Incoloy 825 sheathing, engineered specifically to eliminate chloride-induced pitting, stress corrosion cracking (SCC), and scale bonding from dissolved sodium chloride.

• Passivated / Barrier-Coated Pressure Vessel: Welded heavy-gauge cylindrical chamber fabricated from 316L stainless steel or carbon steel lined with a specialized baked phenolic epoxy/fluoropolymer protective barrier, isolating the substrate from saline electrolytic degradation.

• Sacrificial Cathodic Protection: Equipped with an accessible sacrificial zinc or magnesium anode plug port to absorb galvanic action and mitigate stray current erosion in the salt plumbing loop.

• Corrosion-Inhibited Cabinet: Heavy-gauge NEMA 1 industrial painted enclosure finished with an anti-corrosion powder coating to prevent cabinet degradation in high-humidity, salt-vapor mechanical rooms.

Construction & Safety Architecture

• Cabinet & Enclosure: NEMA 1 industrial painted steel cabinet with a removable front panel for terminal inspections, heavy-duty 2-pole magnetic contactor servicing, and field wire terminations.

• Integrated Safety Controls:

  • Dual-dial adjustable thermostatic controller calibrated up to 104°F (40°C) for commercial spa compliance.

  • Manual-reset High-Limit safety cutout set to de-energize the magnetic contactor control circuit at 122°F (50°C).

  • Pressure/flow-interlock switch preventing heating element contactors from pulling in during low-flow, pump loss, or deadhead conditions.

Hydraulic & Plumbing Specifications

• Plumbing Connections: Standard 1-1/2" NPT female inlet and outlet ports (adapted via Schedule 80 CPVC unions).

• Equipment Sequencing in Salt Systems: Must always be installed upstream of the salt chlorine generator electrolytic cell (with an intervening corrosion-resistant check valve) to prevent concentrated chlorine gas and hypochlorous acid pockets from migrating into the vessel during filtration pump shutdowns.

• Flow Rate Parameters:

  • Minimum Flow Rate: 15 to 20 GPM (approx. 57 to 76 LPM) required to trip the internal safety flow switch.

  • Maximum Flow Rate: 60 to 70 GPM (approx. 227 to 265 LPM); higher circulation filtration loops mandate an external plumbed bypass manifold.

• Maximum Working Pressure: 60 PSI (approx. 4.14 bar).

Dimensions, Net Weight & Shipping Weight

• Unit Dimensions: Approximately 19.5" L × 10.0" W × 14.5" H (approx. 49.5 cm × 25.4 cm × 36.8 cm).

• Net Unit Weight: Approximately 50 to 56 lbs (approx. 22.7 to 25.4 kg).

• Packaged Shipping Dimensions: Approximately 22" L × 13" W × 17" H.

• Packaged Shipping Weight: Approximately 62 to 70 lbs (approx. 28.1 to 31.8 kg) in heavy-duty corrugated carton packaging with protective inserts.

Estimated Temperature Rise Rates

(Calculation: $\text{Rise (°F/hr)} = \frac{61,418\text{ BTU/hr}}{\text{Gallons} \times 8.34\text{ lbs/gal}}$, baseline heat-up rate assuming covered vessel without ambient radiation losses.)