Coupler for Cast Iron Pumps (Fits Series 100, HV, PR, 2")

OMI Parts RM876 Coupler for Cast Iron Pumps, Fits Series 100, HV, PR-2, is a pump coupler used on selected cast iron circulating pumps to connect the motor shaft to the pump shaft and transmit rotation.

Key Features:

• OEM OMI replacement coupler for cast iron circulators
• Designed to fit Bell & Gossett style Series 100, HV, PR-2 and similar pump models that call out this coupler
• Flexible coupling design intended to connect motor and pump shafts while accommodating minor misalignment
• Metal construction suitable for hydronic circulation pump environments

Compatibility & Applications:

• Intended for use on cast iron circulators that specify RM876 as the replacement coupler in OMI or pump manufacturer parts literature
• Commonly used on Series 100, HV, PR-2 and related three-piece circulator pumps in hydronic heating and cooling systems
• Applied in residential and light commercial hot water or chilled water circulation where these pump models are installed

Installation & Operation Notes:

• Disconnect electrical power to the pump and isolate the system as needed before servicing
• Follow pump manufacturer instructions for separating the motor from the pump body to access the existing coupler
• Remove the worn or damaged coupler and install the new RM876 coupler on the motor and pump shafts, aligning set screws with the flats or keyways as specified
• Verify correct shaft spacing and alignment per the pump manual before reassembling the motor to the pump body
• After reassembly, restore power and briefly run the pump to check for smooth, quiet operation without unusual vibration

Maintenance & Troubleshooting:

• Inspect the coupler if abnormal noise, vibration, or loss of circulation occurs, or when performing routine circulator maintenance
• Replace the coupler if rubber or metallic elements show wear, distortion, cracking, or if set screws are damaged
• If repeated coupler failures occur, check for misalignment, bearing wear, or piping strain that could be loading the pump shafts