Flow Switch

Since the mid 1980’s the Harwil Q-12 flow switch has been used by some of the largest companies in the Pool & Spa and fluid control industries. The Q-12 has several factory adjustable parameters that provide the flexibility to meet the requirements of almost any application. The Q-12 verifies fluid flow, typically in conjunction with another device. For example most of swimming pool salt chlorine generators use the Q-12 to verify sufficient flow before the generator is energized. In a spa or hot tub the Q-12 ensures sufficient flow to prevent the water heater from a meltdown. In a chiller the Q-12 prevents the system from freezing. At home the Q-12 turns on the water disinfection system when someone is getting a glass of water.

• Max. flow may be five times normal flow.
• Positive stop eliminates fatigue effects of turbulence, vibration and flow surge on flow detecting element.
• Very low pressure drop – typically less than 1.0 psig at normal flow rate.
• Small size and low profile provides easy mounting in crowded installations.
• Power the driving coil of small ice cube relays as well as some 30A power relays.
• Switches 5VDC to 240VAC.
• Switch employs magnetic coupling.
• Can be used in ¾ inch to 6 inch pipe.

Flow Range: 0.7–590 GPM (2.6–2,233 L/m)

Working Temp: 200˚F (93˚C) Maximum

Working Pressure: 250 psi (1.724 kPa)

Process Connection: 1/2″ NPT, 3/4″ NPT

Electrical (Reed) Switch: SPNO (single pole normally open) 0.5A*

Installation instructions01154992 Q-12N/2/10/NO/1 (PDF)

Data sheet 01154992 Q-12N/2/10/NO/1 (PDF)