Len Gordon (SBSG/ALLIED), 25 amp pressure switch 800150-3 has a stepped hose barb water connection to accept both 1/8"" and 3/16"" water hose, and three wire terminals for common, NC and NO wires. Adjustable pressure switch comes factory set but can be adjusted with the thumb dial, with a clean filter, to meet a variety of system pressures, as low as 1 psi up to 5 psi. Len Gordon pressure switch for LX-10, LX-15 spa control systems.
Pressure switches are used on spa, tub and bath heaters to measure the amount of water pressure inside of the heater, as an approximation of water flow. Pressure switches are safety devices intended to prevent heater damage and overheated water hazards. If your pressure switch is causing the heater to shut down, look for causes of low flow in and out of the heater, and remove the spa filter temporarily to improve flow. Pressure switches do fail eventually (which is why sell replacements), but first assume a flow problem, and not a switch problem.