The HW-Q12DSMSC flow switch is a reliable replacement component designed for spa and hot tub systems. Commonly used across multiple brands, it monitors water flow within the plumbing system and ensures that critical components such as the heater only operate when proper circulation is present, preventing overheating and equipment damage.

• 1/2" MPT Flow Switch – HW-Q12DSMSC
• Accurate Flow Monitoring — Detects water movement within the system to confirm adequate flow before activating the heater or other equipment.
• 1/2" MPT Connection — Standard male pipe thread fitting designed to screw into tees or heater unions on 1.5" or 2" plumbing systems.
• Wide Flow Range — Typically operates within a flow range of approximately 16–23 GPM, suitable for most spa applications.
• Low Power Requirement — Rated around 0.5A, making it compatible with common spa control systems.
• Proven Q-12 Design — Part of the widely used Harwil Q-12 series, known for flexibility and reliability in pool and spa systems.
• Durable Construction — Built to withstand continuous exposure to heat, moisture, and chemically treated water.
• Versatile Application — Used in spas, hot tubs, heaters, and water treatment systems requiring flow verification.
• Compatibility — Fits systems using 1/2" MPT flow switches and replaces part numbers such as 34-0217, 5-20-0025, and other Q-12 series variants. Always verify thread size, flow rating, and connection type before ordering.
• Part No.: HW-Q12DSMSC

Why choose this product?
This flow switch is a critical safety component for your spa system. Replacing a faulty switch restores proper flow detection, prevents dry-fire conditions in the heater, and ensures safe, efficient, and reliable operation of your equipment.