MEP-4042 | Actuator: Proportional, Non-Failsafe, 24VAC, 40 in-lbs, Modular

These compact but powerful direct-coupled actuators provide proportional control for small dampers or valves in HVAC systems. The MEP-4042 models are most typically used to control small modulating zone dampers in underfloor air distribution or simple residential and light commercial zoning applications. They may also be field-applied to KMC VEB-43/46 series valve and linkage assemblies for modulating hydronic heat in appropriate applications.

For easy installation, these models feature six-wire RJ-12 modular jack wiring connections that supply power and signal to the actuators and allow them to be “daisy-chained” together in parallel. Multiple actuators may be driven in parallel from one analog output provided by an analog room thermostat (such as a KMC CTE-5201-16), digital controller with modular jack outputs (such as discontinued KMC BAC-584x models), or another manufacturer’s controller with the appropriate cables.

These proportional actuators accept a 2–10 VDC control signal input from a thermostat, controller, or building automation system. “Anti-jitter” circuitry significantly reduces hunting and needless wear on the actuator and valve packing or damper components (from unnecessary miniscule position changes caused by undamped analog input signals).

At power up, the actuator initiates a self-calibration procedure. It first travels fully CCW and assigns 2 VDC to this position, it then travels fully CW and assigns 10 VDC to that position, and it then begins normal function and goes to the setpoint position.

Like other MEP-4xxx actuators, a minimum torque of 40 (MEP-4042) or 80 (MEP-4842) in-lbs. is available over the actuator’s 95° angular rotation. A non-rotation bracket, to prevent lateral movement, is included with each actuator. A gear disengagement button allows manual positioning of the actuator.

The actuators mount directly to 1/4- to 5/8-inch (6 to 16 mm) round shafts or 1/4- to 7/16-inch (6 to 11 mm) square shafts, eliminating the need for expensive and complicated linkages. However, a crank arm kit is available if needed.