Wednesday, April 24, 2013

Spa Part Glossary (F-M)

Spa Part Glossary of Terms (F-M)

Spa Part Glossary of Terms A-E
Spa Part Glossary of Terms N-Z


Filter (Element, Cartridge)
Spa filter cartridges come in a variety of shapes and sizes. All are extremely important to your spas water chemistry and cleanliness. Filter cartridges consist of a PVC or plastic core wrapped with Reemay™ media & held together by plastic end caps.

Filter Canister
The housing which contains the filter cartridge. Usually inline (pictured) or located underneath the skimmer body

A fuse acts as an overload protection device for your spas electrical components. The fuse will fail when the electrical load exceeds the rating of the internal wire or strip. Fuse ratings will vary based on the circuit board or component requirements. 
On many spa circuit boards, Slow Blow fuses (aka Time Delay fuse) can be found. These types of fuses will allow a short term surge in current to pass without failure, but sustained overload current will blow the fuse. Spa equipment such as motors rely on slow blow fuses as they require high loads for starting up.

Flow Through (Heater)
An inline heater manifold assembly containing a heating element. Varying in length from 8" to 17" this is the most common type of spa heater. Typically mounted below or behind the spa control pack water flows through the heater prior to entering the tub. There is always two element terminals on the top of the tube & some models will have a pressure switch installed into the tube. A clamp is also commonly found on flow through heaters, the clamp is where the hi limit probe attaches to the heater. 

Flow Switch


In the pool and spa industry GFCIs come in a variety of shapes and forms from large breaker box units to plug end & panel mounted. What is a GFCI? GFCIs are designed to prevent electrical shock by breaking the circuit when there is a difference in the currents in the hot and neutral wires. The advantage of a GFCI is that it can detect small amounts of electricity (that your fuse or circuit breaker can’t) and effectively turn off the circuit to avoid potential dangers.*
Pool & Spa GFCIs have mechanical parts and can fail over time causing the spa not to function.

Shotcrete is an industry term to correctly describe "pneumatically applied concrete" - either the wet or dry process. Gunite was a trademark name which became synonymous with pool concrete. As the term "Gunite" is a noun (product name) and not a verb (action), it is impossible to "gunite" anything. As Per the American Shotcrete Association (ASA) the correct terminology is "shotcrete - wet mix" or "shotcrete - dry mix."


High Limit

The spa Hi Limit sensor is an overheat sensor designed to prevent an overheat event in your spa which could damage the equipment or harm the occupants. Most spa's Hi limit is around 108°F. These sensors are integral to the spas electronics, if these parts fail or are faulty the spa will not operate at all. If your Hi limit is faulty it should be replaced not repaired as they are a safety device. 
To learn more about different types of Hi Limits see our post here

Heater Element 

What is a heater element? Spa heater elements are comprised of a filament encased in and insulating powder covered by protective skin. The filament of the element is usually a Tungsten coil which functions similarly to a light bulb. Instead of lighting up when current is applied the element resists & heats up. This heats up the coating which is typically Magnesium oxide. The protective skin which can be incoloy, teflon or titanium allows the element to be immersed in water. 
To learn more about heater elements & trouble shooting click here

Heater Manifold
A heater manifold is the enclosure containing an immersion heater element which allows water to flow through the unit to be heated.

This part is located located inside the wetend (pump housing). Pool and spa impellers are designed to transfer the electric motors shaft motion into a suction effect in order to pump water. The large end of the impeller (left) is the intake where water is drawn into the pump housing. The water is then forced out the discharge which is either on top or side of the wetend. Always replace an impeller with an identical part, impeller HP and electric motor HP are not equivalent.


Spa jets come in a large variety of shapes and sizes. Jets are inserts which may have one nozzle or more which directs air and water into the tub.

Jet Body
A jet body is the housing which remains fixed to the tub after the jet internal has been removed. Jet bodies also contacting plumbing connecting the air & water lines. All jets have a matching jet body, they are not one size fits all. 

JJ Plug
Spa Plug Types


Light Assembly
Portable spas use low voltage lights usually 12V or LEDs. 

CALDERA 2.0kw 240V 3"x11" Vertical Low Flow Heater (with two dry wells) 
Low Flow (Heater)
4KW 120/240v Hawkeye Complete Square heater with cord & pressure switchLow flow heaters are an alternate to flow through heaters, Lo Flow hot tub heaters rely on a circulation pump to carry out heating and filtration. Some spa manufactures choose low flow heaters because they are considered more energy efficient as a small circulation pump is operating continuously for the heating & filtration opposed to a larger jet pump with a low speed. Typically low flow heaters function separately to a spas jets & are installed on their own plumbing.
Low Flow heaters come in two variants, 1" tube style and vertically mounted canisters

Manifold (PVC)
Spa Manifolds are PVC fittings used to divert or split the flow of air/water from a central source to many destination fittings. Manifolds are used for two operations in a spa; Air & water. Manifolds come in many shapes and sizes & their configurations are extremely customizable. To learn more about spa manifolds view our post by clicking this link.

Spa Part Glossary of Terms N-Z