Spa Parts Glossary

At DiscoverMyStore, we carry a variety of spa and hot tub parts. Some of these include components for the pool, hot tub, and spa.

In this article, we'll go over the various terms used for the various components of a spa and hot tub. This glossary will help you identify and discuss these parts easily.

Air Buttons:

Air buttons are used to activate various equipment such as pumps and lights. They can be placed on the spa-side of an air-control system.

Air Injectors:

Air Injectors are used in hot tubs and spas to distribute air from a motor. They are located on the floor or inside the seats of hot tubs.

Air Manifolds:

Air Manifolds are used to split air flow from a pipe into various smaller hose barbs. Manifolds are typically 2" or 1.5" inlet and 3/8" hose barb outlet.

Air Switch:

Air Switches are used to activate various spa and hot tub equipment when using an older style air-control system. These switches can be a simple on-off switch or a more complex multi-function switch.


A bromine feeder or dispenser is a device that automatically adds bromine sanitizer to a hot tub or spa. It can be placed anywhere that has a bromine supply line.


Capacitors are small batteries that help boost the performance of spa pump motors by supplying a low-voltage boost. They are used to generate a magnetic field to reduce the motor's workload.

Check Valve:

A check valve is a one-way flow valve that works for both air and water systems in hot tubs and spas. It allows air to circulate and prevents water from coming in.

Chip Number:

On a printed circuit board, the main chip has a chip number, which often refers to a revision number. When replacing a spa control, make sure to match the revision number and the superseded versions.


A contactor is a type of relay or switch that has high amperage. It's commonly used to control the size of electric heaters such as the Coates C-SPA or the C-SPA.


The Spa Control is the central component of your hot tub. It is capable of controlling various features of the spa, such as the temperature, lights, and music.


A pump diffuser is a device that evenly diffuses the water flow inside a pump. It works by filtering or returning to the spa.


A Diverter is a type of valve that works by diverting the flow of water from one pipe to another. It is commonly used in large spa setups. A diverter is connected to a shaft that activates a spa's jets.


These components are similar to those found on electric hot water heaters and are used when the heater assembly gets damaged. They can be replaced with a new assembly or a different type of heater.


A Escutcheon Plate is a small ring used around a spa jet wall or escutcheon. It's usually a escutcheon or retainer ring that fits around a spa side button.


Spa filter can be defined as the entire filter assembly, or the cartridge that's inside the filter. They are designed to last for up to 24 months in most cases.

Flow Switch:

If the water flow isn't flowing properly, then an electric spa heater can suddenly melt-down. A Flow Switch is an electro-mechanical device that's used to monitor the flow rate of water.

Heat Manifold:

A spa heater manifold is a plastic or steel box that houses an electric spa element. It has connections to the water and the element's sensors.

High Limit Switch:

High Limit Switches are spa heater components that sense the highest limit of water temperature. They are typically used to prevent overheating.


A spa pump impeller is a type of pump that's similar to a boat propeller. It's designed to push water in by producing a loud sound.


Inlets are typically the areas of a hot tub or spa that allow water to flow into it. There are many styles of inlets, including those by G&G, Flow, and Jacuzzi.


The term Spa Jet Body refers to the main housing of a spa jet. Other parts of the jet include the Jet Head, Jet Deflector, and Wall Fit.

Lock Nut:

Lock nuts are used around a variety of spa equipment to secure a filter cover or a wall fitting. They are also commonly used on spa unions.


Hot tub motors are used on jet spa pumps and circulation pumps to turn the Impeller, which is the device that operates the filtration and sanitation equipment in a spa.


A spa jet nozzle is a device that fits into the jet's opening. Most commonly found in inground spas, they are usually used for replacing the jet's orifice tip.


Spa Suction Outlets are located in the spa's main drain and the spa skimmer. These outlets are where the water goes from the tub to a hot tub.


Spa controllers rely on printed circuit boards, often abbreviated PCB's. The quality and design of these components have greatly improved over the years.

Pressure Switch:

A pressure switch is a type of device that is used for measuring the water flow in a spa. It is factory set to open when the minimum pressure is sensed within the heater.


A spa or hot tub pump is essential to the operation of your hot tub and other parts of your circulation system. There are various types of spa pumps, some with dual-speed models and others with single-speed models.


A Spa Relay is a type of electronic switch that's used to control various spa equipment, such as a heater, a pump, and a light. They are usually mounted to a printed Circuit Board.

Shut-off Valve:

A Spa Shut-off Valve is a device that allows you to shut off the water flow to perform various maintenance items on a spa or other water-based equipment.


A surface skimmer is a device that draws water from the surface to remove debris and keep the water running clean. It works in conjunction with a spa drain.

Split-Nut Union:

A split nut union is a type of lock that has two small screws on its side. It's usually used to replace a broken lock.


A tailpiece is half of a Spa Union or a Pump Union. It's a part that slips through the lock ring and connects to the incoming or exiting pipe.

Temp Sensor:

A temperature sensor is used to monitor the water's temperature. It can be used to prevent overheating and display its temperature on the topside control.


There are terminals all over the equipment and control panels of a spa. These are what the wires use to connect to one another. They have terminals that are designed to work seamlessly.


Electronic thermostats are typically used in spa control systems to control the water temperature.


Thermowells are commonly used for holding a temperature sensor. They can be made from various materials such as plastic, metal, or rubber. Wet thermowells are designed to allow the placement of a heavy duty coating on a spa pipe.


Modern spas have timers that allow you to set the time when the pumps run. However, older models use mechanical timers to set program times.


Transformers are used for spa control systems that reduce the voltage from a high to a low voltage. They are usually used for use in low voltage environments.

Topside Control:

The main spa control panel is mounted on the top edge of the spa. It controls the program modes and other features of the spa.


Unions are used to help remove equipment from under baths. They can be easily removed with big hands or by using a strap or a pair of Channel pliers.

Vacuum Switch

A vacuum switch is a type of pump that uses its suction to measure the vacuum pressure. It's similar to a pressure switch, except it's also used to identify the flow of water.


The concept of the Venturi Effect was first presented by Giovanni Battista Venturi in 1797. It is a reduction in fluid pressure that occurs when water is forced through an opening.


Volutes are commonly used for holding pumps. Their shape and design determine the flow characteristics of the pump. They can also be sturdy enough to endure high pressure and freezing water.

Wall Fitting:

Spa Wall Fittings are round and open rings around a spa jet. They are often made with threads that run down the center.


A skimmer weir is a tiny door thingy that's inside of a skimmer. It's a device that helps accelerate the flow of water into the skimmer. It can also stand up when the pump is shut off.

There are a variety of terms for spa parts in the US. Some of these are regional differences, and sometimes even terms that are not used often.


 If you have any other questions about pool and spa products please do let us know - we are here to help!

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