The Q12DS flow switch is a highly popular and versatile component used across the hot tub, spa, and pool industries, primarily manufactured by Harwil Corporation. It serves as a safety mechanism, ensuring sufficient water flow before the heater or other critical components activate, thus preventing damage.
Manufacturer of the Part
Harwil Corporation: Harwil is the original and primary manufacturer of the Q-12DS series flow switches, known for their reliability in fluid control applications.
Coates Heater Company: This company uses the Harwil flow switch as an integral part of its electric heaters, referring to it by its own part number (23000105).
Various Aftermarket Suppliers: Many other companies produce compatible or generic versions of the Q12DS (e.g., XMK, Sixcow)
Spa Brands That Have Used This Part
Due to its widespread use and adaptability, the Harwil Q12DS flow switch has been incorporated into spas from numerous manufacturers, often with a specific connector or tee assembly for that brand:
Cal Spas: The Q12DS is a very common part for Cal Spas models from the mid-1990s onward, often referred to by part number 607979 or 6656-CAL.
Sundance Spas: Used in many models, including 680, 780, 880, and 980 Series.
Jacuzzi Hot Tubs: Used in various J-100, J-200, J-300, J-400, and J-500 series models.
Sweetwater Spas (now part of the Jacuzzi Brands group): Used in all 2003-2004 models.
Beachcomber Hot Tubs: Uses a specific version with a Molex connector (Q-12DS-C2).
L.A. Spas: Another brand that has used the Q12DS flow switch in their systems.
Pentair: Uses Q-12DS switches in some of their pool and spa equipment, including salt chlorine generators.
Key Features and Specifications
Function: Detects water flow to protect heating elements and other equipment from low-flow conditions, which often manifest as "FLO" error codes.
Plumbing Connection: Typically 1/2-inch Male Pipe Thread (MPT), often installed in a separate tee fitting (which can be clear for easy inspection).
Switching Action: Switches on at approximately 10 GPM and off at 8 GPM in 1/2-inch pipes (performance varies by pipe size).
Voltage: Compatible with a range of voltages, from 5 VDC up to 240 VAC.
