Tecmark Pressure Switch [3903-DF Adj SPST] (3903-DF) is a Tecmark replacement pressure switch used in compatible spa and hot tub control systems. Pressure switches help monitor water flow or pressure conditions so equipment can operate with the intended safety logic and control response. A failing or mismatched pressure switch can contribute to heating errors, equipment interruptions, or unreliable system operation. This replacement is intended for service situations where the existing switch specifications, connection type, and rating match the part being replaced. Always compare the PSI rating, threading or fitting style, electrical rating, and original part number before installation. Replacement Tecmark pressure switch for compatible spa control systems Supports proper equipment interlock and heater-control operation Useful when troubleshooting flow, pressure, or heater enable issues Match PSI range, connection style, and electrical rating before ordering Part number 3903-DF provides a reliable reference for service matching
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![Tecmark Pressure Switch [Balboa 2 PSI] (3903-EADE)](https://cdn.shopify.com/s/files/1/1751/9347/files/47-319-3000_XL.jpg?v=1777962213&width=480)