How a Hot Tub Heater Works

Written By
John Yargo
John Yargo
Published: Nov 9, 2009
Updated: Nov 20, 2021
2 minute read

Components

Some hot tubs have tanks to store hot water. More common are tankless hot tubs, which are more efficient and supply more hot water.

Electrical Resistance Heaters

Hot tubs are warmed by electrical resistance heaters. Water courses through the assembly housing, where it comes into contact with an element coil that generates heat. The outside two layers of the assembly housing are the outer sheath (which is often gray) and the compacted filler and insulator.

Heating the Water

One or more pressure pumps send the water through the heater, which is usually located in the cabinet. The water is sent through the assembly, where it comes into contact with the heating coil, which wraps around the cold pin. The heater converts energy from the terminal into heat for the water. If the coil heats for long without water, a “dry fire” might occur. A “dry fire” happens when the heating coil overheats because the water is not absorbing the heat as it should. Damage to the hot tub may result.

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Jetting the Water

After being heated, the water runs to a distribution box, which branches out to the various jet nozzles that lead into the tub itself. The “jet effect” is caused by forcing a significant amount of water through smaller nozzles. The water is continuously heated by the heating system in the tub.

The Drip Cap

  • Every hot tub breaks down into two components: the shell and the cabinet.
  • The water is sent through the assembly, where it comes into contact with the heating coil, which wraps around the cold pin.
  • A “dry fire” happens when the heating coil overheats because the water is not absorbing the heat as it should.
  • The water is continuously heated by the heating system in the tub.
John Yargo

John Yargo is a sports writer, living in Orlando, Fla. His work regularly appears in the "Jackson Free Press," and he has published articles on theater, fiction and art history. He has also received a master's degree in English.

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