The model MR Modulo Adjustable Constant Airflow Regulator is a modulating orifice that automatically regulates airflows in duct systems to constant levels.

The passive control element responds to duct pressure and requires no electric or pneumatic sensors or controls.

The MR Modulo compensates for changes in duct pressure caused by thermal stack effect, building pressure, dust-clogged filters, etc.

The MR Modulo also provides a quiet, low-cost solution to balancing forced-air systems for heating, air conditioning and ventilation, eliminating the need for onsite balancing.

The MR Modulo will regulate airflow in supply, return, or exhaust duct systems. It can be mounted horizontally or vertically, and can be fitted in ductwork and accessories.

The active control element of the MR Modulo is a flexible bulb that inflates and deflates in response to the static pressure difference across the control.

This operation regulates the freearea opening through the control, resulting in maintenance of velocity and specific airflow setpoints. Each MR Modulo is designed and produced for control of air in temperatures ranging from 14° to 140°F (-10° to 60°C).