More Value From Your Pool Investment

  • An OTF pool heater maintains temperature with fuel efficiency and low maintenance
  • OTF boilers have economical, low-maintenance operation
  • A pool heater can also heat a pool enclosure or adjacent building
  • Pool heaters add fun by giving you a longer swimming season
  • Pool water stays at the temperature you select
  • OTF pool heaters have no problems with corrosion or scaling
  • Every OTF pool heater has a Hydrolevel low water cutoff

  • Pool heaters preserve the beauty of your pool area since there is no chimney or special housing needed
  • An OTF pool heater is easily and quickly installed

OTF Design Features

  • Durable, long lasting construction. Built to National Board Specifications.
  • All-copper indirect heat exchanger design practically eliminates corrosion, scaling and condensation problems
  • Aluminized flue collector and firebox assembly withstands atmospheric corrosion
  • Flame retention forced draft oil burner provides efficient combustion; easy access for maintenance and adjustment; UL listed components
  • Precast refractory combustion chamber is surrounded by insulating pellets to keep heat loss through the base to a minimum
  • Preassembled for ease of installation

Standard Features

OTF- powder coated galvaneal jacket, boiler body with combustion chamber installed, theraltimeter, completely assembled and packaged with oil burner, cadcell relay, pool & limit control, relief valve, indirect standard pool heating coil OTF-150 (510/801) OTF-200 (1010/1600) with 1 1/2″ I.P.S. tappings. Cupr Nickel pool heating coil for Salt Water Applications OTF-150-CN (510/801) OTF-200-CN (1010/1600) option available.

There are many factors related to proper sizing of pool heater. We recommend that you contact your installing dealer for help in determining the correct size for your particular application. A Properly Sized Swimming Pool Heater will gain 20 to 24ºF in 24 hours.

Surface Area of Pool, Sq. Ft.Desired Pool Temperature (°F)Approximate Gallons
500137,000 BTU155,000 BTU200,000 BTU20,000
600166,000 BTU185,000 BTU240,000 BTU24,000
700200,000 BTU218,000 BTU280,000 BTU28,000
800220,000 BTU250,000 BTU320,000 BTU32,000
900248,000 BTU280,000 BTU360,000 BTU36,000
1000275,000 BTU310,000 BTU400,000 BTU40,000
1200330,000 BTU370,000 BTU480,000 BTU48,000
1400384,000 BTU435,000 BTU560,000 BTU56,000
1600 or largerRefer inquiry to Thermo-Dynamics.
Note 1: These heat losses are based on an assumed wind velocity at the water surface of 5 m.p.h. and an ambient temperature of 60°F.
Note 2: Where surface area and gallons do not coincide, surface area must take precedence. For more information on heat loss from spa surfaces, contact Thermo-Dynamics


MODELSOTF 510OTF 801OTF 1010OTF 1600
Gross Input BTU/hr140,000210,000280,000350,000
Gross Output BTU/hr109,200163,800218,400273,000
Flue Pipe Diameter6"6"8"8"
Firing Rate GPH1.001.502.002.50
Width22"22"26 ¼"26 ¼"
Height38 ½"38 ½"45"45"
Approximate Shipping Weight397434685730
*Use Gross Output - BTU/HR to estimate boiler size

OTF Pool Heater Manual

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Swimming Pool Heater Warranty

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