63-2202—4    B.B.  Rev. 11-00  www.honeywell.com
Printed in U.S.A. on recycled 
paper containing at least 10% 
post-consumer paper fibers.
SERIES 72 MODUTROL IV™ MOTORS
Home and Building Control Home and Building Control Honeywell Asia Pacific Inc. Honeywell Europe S.A. Honeywell Latin American
Honeywell Honeywell Limited-Honeywell Limitée Room 3213-3225 3 Avenue du Bourget   Region 
1985 Douglas Drive North 35 Dynamic Drive Sun Hung Kai Centre 1140 Brussels 480 Sawgrass Corporate Parkway
Golden Valley, MN  55422 Scarborough, Ontario No. 30 Harbour Road Belgium Suite 200
M1V 4Z9 Wanchai Sunrise FL  33325
Hong Kong
OPERATION AND CHECKOUT
Operation
The motor feedback potentiometer and control current input 
circuit form a bridge circuit. As long as the final control 
element remains at the position proportional to the input 
current from the controller, the circuit is balanced, and the 
motor does not run. When the value of the controlled medium 
changes, the current from the controller changes, and 
unbalance is amplified to energize the Triac switching to run 
the motor in the proper direction to correct the change in the 
temperature or the pressure. The motor turns the feedback 
potentiometer to rebalance the circuit and stop the motor.
Checkout
After installation and linkage adjustment, operate the motor 
through the controller. Make sure that:
• The motor properly operates the damper or valve.
• The motor responds properly as the input is varied.
• The auxiliary switch, if used, operates at the desired point 
of motor rotation.
Inspect the motor, linkage, and valve or damper to see that all 
mechanical connections are correct and secure.
In damper installations, the pushrod should not extend more 
than a few inches past the ball joints. Check to see that 
there is adequate clearance for the linkage to move through 
its stroke without binding or striking other objects.
See controller or system instructions for additional checkout 
procedures.
Motor Operation Checkout
Check motor operation as follows:
1.
To close the motor, open terminals +, -, and F.
2.
To open the motor, connect terminal F to the 
negative (-) motor terminal.