Part number 34-0203D refers to a temperature sensor manufactured by HydroQuip, designed for use with Gecko M-Class and S-Class control systems.
It is also standard on numerous HydroQuip control series, including the CS6200, CS7500, and CS9700.
Because these Gecko and HydroQuip systems are sold to many Original Equipment Manufacturers (OEMs), this sensor is used by a broad variety of spa brands.
Spa Manufacturers Using Sensor 34-0203D
The following brands have models known to use this sensor or the compatible Gecko/HydroQuip control packs:
Artesian Spas
Aqua Terra
Cal Spas
Coast Spas
Coleman Spas
Dream Maker Spas
Gulf Coast Spas (specifically the Cool Nights series, 1999–2005)
Hydro Spa
Jacuzzi (older models using Balboa/Gecko systems like Z150/350)
Marquis Spas
Master Spas
Platinum Spas
Saratoga Spas
Sundance Spas (certain older models)
ThermaSpa
Vita Spas
Compatibility Details
Alternative Part Numbers: You may see this part listed as 9920-400262 (Gecko), 9920-400342, or 9920-400723.
Control Systems: It is a direct fit for the Gecko SSPA, MSPA, and USPA series, as well as EasyPak (EP1500X, EP2000, EP3000) systems.
Specifications: This sensor typically features a 4-pin connector (usually with 2 wires), a 3/8-inch diameter bulb, and a 10-foot cable. Note that versions with different cable lengths (e.g., 36", 72") use the same part number with a suffix (34-0203D-36)
