Grundfos mri Magnetic Run Indicator Key

Product Description

The GRUNDFOS mri is a magnetic run indicator tool designed to confirm whether a circulator pump is actively running. It works by detecting the rotation of internal pump components through the pump housing wall using a magnetic dial. When placed against the side of a circulator pump, the dial rotates if the pump is circulating fluid. This eliminates the need to rely on vibration feel or audible cues, which are often unreliable on modern low-noise circulators. The mri is compact enough to attach to a key ring and carry on every service call.

The mri is intended for use by plumbers, HVAC technicians, and hydronic system service professionals who regularly work on residential or light commercial circulator pump installations. Modern wet-rotor and ECM-based circulators operate so quietly that confirming pump operation by sound or touch alone is not practical. The mri provides a fast, definitive check without removing the pump from the system or interrupting service.

Key Features

• Magnetic dial detects internal rotor rotation through the pump housing
• Compact key-ring form factor for everyday carry
• No batteries or external power required
• Works on quiet modern circulators where vibration and sound checks are unreliable
• Provides immediate visual confirmation of pump operation

Compatibility

Designed for use with circulator pumps where magnetic detection through the housing wall is effective. No specific model compatibility data was provided by the manufacturer for this listing.

Installation Notes

No installation is required. To use, hold the mri flat against the side of the circulator pump body near the motor section. A rotating dial indicates the pump is running. No tools or system shutdown are needed for this diagnostic check, but standard service safety practices should be observed when working near live electrical equipment.