The M847D is a two position, 24 Vac spring return damper
actuator designed to operate directly driven zone dampers,
used to control air flow in ducts. The synchronous motor
actuator can be driven open (or closed) using any 24 volt
rated two position switch - eg. a wall switch or a thermostat
The M847D replaces the RDMH and RDMZ damper
actuators for use on Trol-A-Temp® ARD and ZD dampers.
Electrical Rating: 24 Vac 60 Hz 0.32 Amp., 8 VA
Electrical Connection: 1/2" conduit
Nominal Angular Rotation: 90° ( max. 105° )
Torque: Min. 423 mNm (milli newton meter) [60 in.oz] output
torque available when motor is energized and device is at
the spring returned initial start position.
Nominal Motor Timing: (@25°C ambient)
Energized at rated load - 30 seconds.
De-energized (spring return) - 10 seconds.
Ambient Temperature Rating: 5 to 60°C (+40 to 140°F)
Finish: zinc plated steel, anodized aluminium
Direction of Shaft Rotation: clockwise, when energized
and viewed from the base or shaft end.
Mounting Means: direct connection to damper shaft.
Mounting Position: Multi-poise.
Dimensions: See Figure 1.
Fig. 1 - Dimensional Details
INSTALLATION AND CHECKOUT
1. Read these instructions carefully. Failure to follow them could
cause a hazardous condition.
2. Disconnect powersupply before beginning of installation and
wiring of control to prevent electrical shock or equipment
3. Check the ratings given in the instructions and on the product
to make sure the product is suitable for your application.
4. All wiring must comply with local electrical codes, ordinances,
5. Installer must be a trained, experienced service technician.
6. After installation is complete, check out the product operation
as provided in these instructions.
Direct Drive Damper Actuator
Nominal Device Dimension
1. DO NOT install this actuator on a flue damper.
2. DO NOT attempt to rotate the actuator by turning the
connection coupling or the damper shaft when it is
connected to the actuator or damage to the gear train
STANDARD MOUNTING (For 5/16" dia. damper shaft)
The M847D can be attached directly to the protruding 5/16"
diameter damper shaft using the sleeve of the output shaft. Drill
A 5/16" (8mm) hole 1-5/16" (33.5mm) directly below the damper
shaft opening to accept the anti-rotation shaft protruding from
the base of the motor. The length of the damper shaft to which
the connection coupling is attached is such as to firmly hold the
actuator in a position to adequately engage the anti-rotation pin
in the warm air duct. See Figure 1. for the critical dimensions.
11-01 © Honeywell Limited. 2001 • Form Number: 95C-10905-1