Mcdonnell Miller 114780 Flow Switch 150 Psi 1.5-15 Gpm

Product Description

The MCDONNELL MILLER 114780 is a general purpose liquid flow switch housed in a brass body and rated for up to 150 psi operating pressure. It monitors flow in liquid piping systems and triggers a switching action when flow reaches a set point, making it a reliable control component for pumping and HVAC hydronic applications. The switch covers a flow range of 1.5 to 15 GPM and connects via threaded NPT fittings. At 3.438 inches in overall length, it fits neatly into tight mechanical spaces. Licensed plumbers and HVAC technicians are the primary installers for this type of device.

This flow switch is suited for residential and light commercial liquid systems where flow confirmation or flow-loss protection is needed. Typical applications include chilled water loops, hot water heating systems, pump protection circuits, and general process liquid lines. The NEMA 1 enclosure rating makes it appropriate for indoor, non-condensing environments. It is not rated for outdoor or washdown service without additional protection.

Key Features

• Brass housing for corrosion resistance in liquid service applications
• 150 psi maximum operating pressure rating
• Flow range of 1.5 to 15 GPM with a defined flow set point
• Threaded NPT connection style for standard pipe installations
• NEMA 1 enclosure rating for protected indoor environments
• Compact overall length of 3.438 inches for space-constrained installations

Compatibility

Designed as an OEM-style replacement or new-installation flow switch for general purpose liquid piping systems using standard NPT threaded connections.

Installation Notes

Installation should be performed by a licensed plumber or qualified HVAC technician in accordance with applicable local plumbing codes and the International Plumbing Code (IPC). Shut off and depressurize the liquid system completely before threading the switch into the pipe. Apply thread sealant or PTFE tape to NPT threads per standard practice, and do not overtighten, as brass fittings are susceptible to thread damage. Verify flow direction matches the switch orientation before restoring system pressure.