Submittal Sheet

ML6984, ML7984 SERIES 4000 DIRECT COUPLED VALVE ACTUATORS
11
95C-10939—6
NOTE: The 272630D position feedback/auxiliary switch
module cannot be used with ML6984
3-wire installation. The 272630D requires
continuous power.
To Replace ML6874:
1. The ML6984 is a direct replacement for the old
ML6874 in single actuator hook-up.
2. For parallel, multiple ML6874 actuators applications,
an isolation relay must be used. The isolation relay
contacts should be placed in the new ML6984 actuator
signal input "W" and "B" circuit.
To Replace Line Voltage Auxiliary
Switches:
These accessories are no longer available. Replace the old
ac tu a tor with new model and 272630D position feedback/
auxiliary switch module.
Operate an external relay, such as R8845U, using the
adjustable SPDT pilot duty output on the 272630D.
If a second, independent output switch is needed, wire
the 2-10 Vdc position feedback signal to an Approved,
adjustable, voltage-controlled relay.
CHECKOUT
ML7984:
1. Make sure the valve stem is completely screwed into
the actuator drive shaft with no threads showing before
applying power.
2. Make sure the valve stem is locked in place with the
set screw.
3. Make sure the Confi guration DIP switches are
set correctly.
4. With 24 Vac or 28 Vdc power source connected to
T5 and T6, actuator operation can be ver i fi ed by
con nect ing appropriate control signal (Series 70/90)
from con trol ler to the signal input terminals (Figures 8
thru 16). For direct acting: A mod u lat ing action can be
obtained by increasing the control signal. The actuator
will travel from stem down to stem up. On signal failure
(dis con nect ed/no signal), actuator de faults to closed
position. For reverse acting: De creas ing controller
signal will drive actuator from full stem down to full
stem up. On signal failure (disconnect/no signal),
actuator defaults to open position.
5. Operate the system (valve, actuator, and controller) for
several cycles to ensure proper installation.
6. When checkout is complete, return the controller to the
desired setting.
NOTE:
1. Device will ignore any input changes until it has
completed its repositioning relative to the initial
signal input.
2. 272630D position feedback/auxiliary switch
module is inactive during self-calibration.
ML6984: 5-Wire Installation:
1. Make sure the valve stem is completely screwed into
the actuator drive shaft with no threads showing before
applying power.
2. Make sure the valve stem is locked in place with the
set screw.
3. Connect 24 Vac or 28 Vdc power to T5 and T6.
4. Jumper R and B. The valve stem should move up.
5. Jumper R and W. The valve stem should move down.
6. For Floating operation, open R connection Valve stem
should remain in position.
7. Re-connect all control wiring.
8. Operate the system (valve, actuator, and con trol ler) for
several cycles to ensure proper in stal la tion.
9. When checkout is complete, return the controller to the
desired setting.
ML6984: 3-Wire Installation:
1. Make sure the valve stem is completely screwed into
the actuator drive shaft with no threads showing before
applying power.
2. Make sure the valve stem is locked in place with the
set screw.
3. Connect 24 Vac to T6.
4. Manually override the controller to signal the
actuator to open/close for a few cycles to ensure
proper installation.
5. When checkout is complete, return the controller to the
desired setting.
TROUBLESHOOTING
SYMPTOM POSSIBLE CAUSES ACTIONS
Valve seat leaks or will not close
properly
Wrong actuator used and/or system head
pressure too high
1) Check valve close-off rating
2) Check voltage at actuator terminals
Actuator not properly installed
Ensure valve stem is fully threaded into
brass drive shaft and locked in place with
the set screw
Incorrect DIP switch settings Check against Product Instruction Sheet
Noisy motor
Bearing failed due to overheat
1) Check for excessive temperature and
replace complete actuator
2) Use high temperature kit
(43196000-001)
Brushes worn out Check for excessive cycling and replace
actuator or brushes (part no. 272775)