Air Switches
Often these switches are found in controls for motors/pumps. When replacing switches take the extra step to insure you get the correct version as there are two. They will appear the same but they are functionally different.
Alternate/Latching/Permanent Style:
This type of switch maintains its position once activated.
Push to turn on, push to turn off.
These switches usually have an A or LC in the part number e.g. TVA-111A
Momentary Style:
This type of switch is only on while the switch is pressed.
Press to turn on, Release to turn off.
Typically switches of this variety have "M" in the part number e.g. TVM-111A
Common Air switches found in Spas:
SPST - Simple on/off switch, aka two-way switch e.g. light switch
SPDT - Simple change over switch, aka three-way switch
DPST - One switch mechanism with two SPST switches, aka double pole
DPDT - One switch mechanism with two SPDT switches, aka double pole
Pressure Switches
This form of switch commonly found on pool & spa heaters gas or electric. These switches use pressure (psi - either rising or falling) to activate or deactivate an electrical contact when a set pressure is achieved.
Common Pressure switch configurations:
