Coates Electric Pool Heater, 18kw 208V Three Phase

The Coates 18kW 208V Three-Phase Electric Pool & Spa Heater (Model 32018CE / 32018CPH) is a commercial-grade inline immersion water heater engineered for municipal hydrotherapy tanks, high-occupancy hotel spas, athletic training plunge pools, and wellness facilities operating on a standard 208V 3-phase/4-wire commercial distribution network.

Balancing 18kW across three phase legs drops the running line current to 50 Amps, allowing the unit to deliver substantial thermal recovery rates with standard, readily available 70A 3-pole distribution gear.

Electrical & Heating Performance

• Model Designation: Coates 32018CE / 32018CPH series (320 designates 3-Phase, 208V).

• 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: 208V AC, Three-Phase (3Ø), 3-pole / 3-wire plus ground (or 4-wire Wye), 60 Hz.

• Full Load Amperage (FLA): 50.0 Amps

  $$\text{FLA} = \frac{18,000\text{ W}}{208\text{ V} \times \sqrt{3}} = \frac{18,000}{360.26} \approx 49.96\text{ A}$$

• Overcurrent Protection (Breaker Sizing): Requires a dedicated 3-pole 70-Amp circuit breaker conforming to NEC 125% continuous-duty branch requirements ($49.96\text{ A} \times 1.25 = 62.45\text{ A}$ minimum branch rating, standardizing on a 70A 3-pole breaker).

• Conductor Sizing: Minimum #4 AWG or #3 AWG THHN/THWN copper conductor (rated 75°C/90°C terminals, adjusted for conduit run distance and raceway ambient derating).

Construction & Safety Architecture

• Pressure Vessel: Heavy-gauge, welded cylindrical steel/stainless steel pressure chamber treated internally with a baked corrosion-resistant protective coating to endure continuous commercial water flow and aggressive sanitizing chemicals.

• Heating Elements: Screw-plug commercial immersion elements sheathed in premium Incoloy 800/825 or Titanium alloy, engineered to prevent chemical pitting, scaling, and high thermal stress.

• Cabinet & Enclosure: NEMA 1 industrial painted heavy-gauge steel cabinet with a removable front access panel for terminal inspections, 3-pole magnetic contactor servicing, and 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.

• Flow Rate Parameters:

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

  • Maximum Flow Rate: 60 to 70 GPM (approx. 227 to 265 LPM); filtration loops operating at higher GPM 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 molded foam protection.

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.)