Many hot tubs and spas utilize an air switch to control various functions of the tub. An air switch consists of a pneumatic air button located at spa-side and a pneumatic-activated electrical, air switch located with the spa electronics. The only connection between the two is a small air hose. This arrangement eliminates the shock hazard of activating a regular switch energized with 120 volts or 220 volts with wet hands while submerged in water. Troubleshooting involves determining if the problem is with the pneumatics or the electronics.
Turn the power off to the hot tub. Open the door to the spa electronics. Push the air button for the suspect switch and listen for the audible click of the electrical portion of the switch. If no click is heard, check the pneumatic tubing for holes or a loose connection and replace accordingly. Repeat the air button and listening for the click. If a click is heard, turn the power on and verify correct operation of the switch circuit.
Turn the power off to the hot tub. Remove the pneumatic tubing from the suspect switch and install a air button that is known to work. Repeat the air button and listening for the click. If a click is heard, turn the power on and verify correct operation of the switch.
Turn the power off to the hot tub. Determine the type of switch for the suspect switch by looking up the identification number or by counting the number of poles. Air switches are single pole single throw (SPST) with two poles, single pole double throw (SPDT) with three3 poles, double pole single throw (DPST) with four poles, double pole double throw (DPDT) with six poles, or multifunction sequential a with varying number of poles .
Connect the multimeter to a set of power leg/switch leg poles. Since there are only two poles on a SPST air switch, make the connection to each pole. Operate the air button. The multimeter should, alternately, show continuity and no continuity, as the air button is operated. If the the multimeter does not show continuity of the air switch, replace the switch.
Repeat the continuity test while operating the air button for each set of power leg/switch leg poles. If any of the pole sets fail to switch on and off, the switch is non-functional and should be replaced with a similar air switch.