63-2516-07
ML6425, ML7425 Spring Return
Electric Linear Valve Actuators
PRODUCT DATA
FEATURES
ML6425 and ML7425
• Accurate valve positioning.
• Quick and easy installation.
• No separate linkage required.
• On power failure:
ML6425A and ML7425A drive valve stem down.
ML6425B and ML7425B draw valve stem up.
• Conduit connector is standard.
• No adjustments required.
• True spring return on power failure.
• Low power consumption.
• High close-off ratings.
• Force-limiting end switches.
APPLICATION
The ML6425 Spring Return Electric Linear Valve Actuators are
floating control actuators used with controllers that provide a
switched or floating single-pole double-throw (spdt) output.
These actuators operate standard Honeywell valves in
heating, ventilating, and air conditioning (HVAC) applications.
The ML7425 Spring Return Electric Linear Valve Actuators are
modulating control actuators used with controllers that provide
an analog output of 0 to 10 Vdc or 2 to 10 Vdc. These
actuators operate standard Honeywell valves in heating,
ventilating, and air conditioning (HVAC) applications. An
internal selector plug can be used to reverse the direction of
action.
• Direct/reverse action.
• Synchronous motor.
• Corrosion resistant design.
• Maintenance free.
ML7425
• Position Feedback signal.
• Fail-safe position selection for control signal loss.
Contents
Application ........................................................................ 1
Specifications ................................................................... 2
Ordering Information ........................................................ 2
Installation ........................................................................ 3
WIring ............................................................................... 4
Operation .......................................................................... 7
Checkout .......................................................................... 8
ML6425, ML7425 SPRING RETURN ELECTRIC LINEAR VALVE ACTUATORS
SPECIFICATIONS
Models:
Model Spring Return Action Description
ML6425A Drive valve stem down on power
ML7425A
ML6425B Draw valve stem up on power
ML7425B
Dimensions: Refer to Fig. 1.
Weight: 5.1 lb (2.3 kg).
Electrical Ratings:
Power Input: 24 Vac ±15%, 60 Hz.
Power Consumption:
ML6425: 11 VA maximum at 24 Vac.
ML7425: 12 VA maximum at 24 Vac.
Signal Source Output Resistance: 1 kOhm maximum.
Signal Load: 1 mA maximum.
Signal Inputs (Supply Voltage Between Terminals):
ML6425:
B and 24 Vac: Drive valve stem down.
W and 24 Vac: Draw valve stem up.
ML7425: 0 to 10 Vdc or 2 to 10 Vdc.
Stem Force: 135 lbf (600 N).
Actuator Stroke: 3/4 in. (19 mm).
Actuator Run Time at 60 Hz: 90 seconds.
Spring Return Time: 12 seconds.
Temperature Ranges:
Ambient: 14° to 122° F (-10° to +50° C).
failure
failure
Electric
Linear Valve
Actuator
Storage: -40° to +158° F (-40° to +70° C).
Maximum Valve Medium: 300° F (149° C).
Humidity: 5 to 95 percent relative humidity, noncondensing.
Close-off Pressure Ratings: Refer to Table 1.
Protection Standard: IP54.
Approvals:
Underwriter’s Laboratories, Inc. UL94-5V Flame Retardant.
Meets CE requirements.
Cable entry: Conduit connector and one knockout on case.
Actuator Material:
Cover: ABS-FR plastic.
Base: PBTP-FR plastic.
Yoke: Diecast aluminum.
Accessories:
43196000-001 High Temperature Kit (for actuators with
3/4 in. stroke). Increases the maximum temperature to
428°F (220°C).
43196000-102 High Temperature Kit (for actuators with
1-1/2 in. stroke). Increases the maximum temperature to
428°F (220°C).
43191679-111 Single Auxiliary Potentiometer (10K ohm).
43191679-112 Single Auxiliary Potentiometer (220 ohm).
43191680-102 Dual Auxiliary Switch (24 Vac use only).
ML6420/ML6425 Only
43191679-101 Single Auxiliary Potentiometer.
43191679-102 Single Auxiliary Potentiometer.
43191679-103 Dual Auxiliary Potentiometer.
43191679-104 Dual Auxiliary Potentiometer.
43191680-105 Dual Auxiliary Switch (24 Vac use only).
ML7420/ML7425 Only
43191680-205 Dual Auxiliary Switch (24 Vac use only).
ORDERING INFORMATION
When purchasing replacement and modernization products from your TRADELINE® wholesaler or distributor, refer to the
TRADELINE® Catalog or price sheets for complete ordering number.
If you have additional questions, need further information, or would like to comment on our products or services, please write or
phone:
1. Your local Honeywell Automation and Control Products Sales Office (check white pages of your phone directory).
2. Honeywell Customer Care
1885 Douglas Drive North
Minneapolis, Minnesota 55422-4386
3. http://customer.honeywell.com or http://customer.honeywell.ca
International Sales and Service Offices in all principal cities of the world. Manufacturing in Belgium, Canada, China, Czech
Republic, Germany, Hungary, Italy, Mexico, Netherlands, United Kingdom, and United States.
63-2516—07 2
ML6425, ML7425 SPRING RETURN ELECTRIC LINEAR VALVE ACTUATORS
CAUTION
CAUTION
CAUTION
Table 1. Close-off Ratings for ML6425, ML7425 Electric Linear Valve Actuators and Honeywell Valves (psi).
Type Valve 1/2 in. 3/4 in. 1 in. 1-1/4 in. 1-1/2 in. 2 in. 2-1/2 in. 3 in.
FlangeV5011A ——————2816
V3350/ 3351/ 3450/ 3451 — —————2114
V5013B, C; V3360/ 3361/ 3460/ 3461 — —————
NPT V5011F, G
150
a
21
b
150
b
150
b
134
b
77 49 28 16
14
a
V5011H, J 150 150 150 145 — — — —
V5011N1xxx, V5011N3xxx, V5013N 230 230 163 104 67 37 — —
V5011N2xxx 100 100 100 100 67 37 — —
V5013F 150 150 150 126 77 49 — —
a
Represents maximum pressure difference between the outlet and either of the two inlets.
b
Do not exceed 100 psi with V5011G valves used in steam applications.
Location
5-5/15
(135)
2-11/16 (67)
6-5/16
x
(161)
14-5/16 (364)
MINIMUM
CLEARANCE
11-1/4
(284)
Install the actuator in a location that allows enough clearance
for mounting accessories and for servicing.
Equipment Damage Hazard.
Can damage actuator due to condensation or a
valve gland leak.
Install the actuator in a position above horizontal.
1/2 (13) FPT
7-5/8
(192)
YOKE
DIAMETER
1-3/8 (35)
M7892A
Fig. 1. Approximate Dimensions of ML6425, ML7425
Electric Linear Valve Actuator in in. (mm).
INSTALLATION
When Installing this Product...
1. Read instructions carefully. Failure to follow them could
damage the product or cause a hazardous condition.
2. Check ratings and description given in the specifications
to make sure the product is suitable for your application.
3. Installer must be a trained, experienced service
technician.
4. After installation is complete, check out product
operation as provided in these instructions.
Electrical Shock or Equipment Damage Hazard.
Can shock individuals or short equipment circuitry.
Disconnect power supply before installation.
Mounting
1. Place the actuator on the valve with the U-bolt around
the valve collar (Refer to Fig. 2).
2. Place the U-bolt against the valve collar and secure the
actuator to the valve by turning each U-bolt nut
clockwise. To assure even pressure on the collar, first
tighten the nuts finger-tight and then alternate turning
each U-bolt nut until both are snug.
3. Push aside the stem button retaining clip and hold
(Refer to Fig. 3).
4. Lift valve stem until the head of the valve stem button is
inside the large slot of the stem button retaining clip on
the actuator.
5. Release the stem button retaining clip to secure the stem
button. Check to make certain the stem button is secured
by the retaining clip.
6. Remove the cover from the actuator using a Phillips or
crosspoint screwdriver (Refer to Fig. 4).
Personal Injury Hazard.
Manual spring handle under tension can turn
quickly when lifted, pinching fingers between
handle and plastic casing.
Use a screwdriver to lift and release manual spring
handle (Refer to Fig. 5).
7. Remove the manual spring handle retaining clip, and lift
and release the handle (Refer to Fig. 5). The easiest way
to perform this operation safely is to:
a. Remove the retaining clip.
b. Wedge a small, flat-bladed screwdriver under the
manual spring handle and pry up the handle
(Refer to Fig. 5).
3 63-2516—07
ML6425, ML7425 SPRING RETURN ELECTRIC LINEAR VALVE ACTUATORS
CAUTION
CAUTION
M6632
M6633
M6630
Fig. 5. Removing Spring Retaining Clip and Releasing
M6629
Manual Spring Handle.
Fig. 2. Attaching Actuator to Valve Collar.
Fig. 3. Securing Actuator to Valve.
WIRING
Electrical Shock or Equipment Damage Hazard.
Can shock individuals or short equipment circuitry.
Disconnect power supply before installation.
All wiring must comply with local electrical codes, ordinances
and regulations. Voltage and frequency of the transformer
used with the actuator must correspond with the power supply
and actuator characteristics. Refer to Figures 6 through 13 for
connection information and typical wiring hookups.
1. Feed power and control wires through the conduit
connector located on the bottom of the actuator case
(See Fig. 6).
Equipment Damage Hazard.
Conduit connection or removal can break an
unsupported connector.
When removing or attaching conduit, use a wrench to
support the motor connector.
2. Using the wiring diagram in Fig. 7, connect power and
control wires. Make sure that all wiring is correct.
3. When wiring is complete, replace the cover on the
actuator (Refer to Fig. 14).
4. Apply power and control signals to the actuator.
M6627
Fig. 4. Removing Actuator Cover.
63-2516—07 4
Fig. 6. Connecting Power and Control Wiring.
ML6425, ML7425 SPRING RETURN ELECTRIC LINEAR VALVE ACTUATORS
WIRING
STRIP
T5
T1
W
B
1
L1
(HOT)
L2
T
Y
G
ML6425A,B
2
4
3
POWER SUPPLY. PROVIDE DISCONNECT MEANS
AND OVERLOAD PROTECTION AS REQUIRED.
ALL WIRING BLOCKS HAVE THE SAME
NUMBER OF TERMINALS (8), BUT THE ONLY
TERMINALS THAT ARE ACTIVE ON THIS
BLOCK ARE T1, T5, W, AND B.
THE T-Y-G TERMINALS ARE A THREE TERMINAL
WIRING BLOCK SEPARATE FROM THE MAIN
BLOCK. THEY DO NOT APPEAR ON ALL MODELS
BECAUSE THEY ARE FOR A SINGLE FEEDBACK
POTENTIOMETER (10K OR 220 OHMS). THE
REQUIRED WIRING BLOCKS ARE PART OF
THE POTENTIOMETER ACCESSORY KITS.
MOTOR OPEN SIGNAL DRAWS VALVE STEM
UPWARDS. MOTOR CLOSE SIGNAL DRIVES
VALVE STEM DOWNWARDS.
1
2
3
4
T6984 (FLOATING CONTROLLER)
M25446
MOTOR OPEN
MOTOR CLOSE
COMMON
24 Vac
POWER SUPPLY. PROVIDE DISCONNECT MEANS
AND OVERLOAD PROTECTION AS REQUIRED.
TS MUST BE POWERED, OR THE ACTUATOR WILL
SPRING RETURN.
ML7425A,B
WIRING
STRIP
F
+
Ð
T2
T1
O1
O2
TS
1
2
2-10 Vdc OUTPUT
T7984
(2-10 Vdc
CONTROLLER)
24 VAC
COMMON
2
1
L1
(HOT)
L2
M17394
L1
(HOT)
L2
1
1
WIRING
STRIP
F
+
–
T2
T1
O1
O2
TS
1
1
2
2
3
3
4
5
6
L1
(HOT)
L2
1
ML7425
T775
(WITH 2-10 VDC OUTPUT)
DUAL
TRANSFORMERS
POWER SUPPLY. PROVIDE DISCONNECT MEANS
AND OVERLOAD PROTECTION AS REQUIRED.
M7894
SENSOR
ML7425
WIRING
STRIP
F
+
–
T2
T1
O1
O2
TS
1
POWER SUPPLY. PROVIDE DISCONNECT MEANS AND
OVERLOAD PROTECTION AS REQUIRED.
2
2-10 Vdc FEEDBACK SIGNAL. SEE OUTPUT SIGNAL
FEEDBACK SECTION.
3
0-10 Vdc OR 2-10 Vdc CONTROL SIGNAL. SEE SIGNAL
INPUT (+) SECTION.
2
F
+
–
INPUT
(FEEDBACK)
OUTPUT
3
1
L1
(HOT)
L2
C8286B
Fig. 7. ML6425 Wiring.
Fig. 8. ML7425 Wiring.
Fig. 9. ML7425 Wiring using Controller Feedback Output
and a Common Transformer.
Fig. 10. ML7425 Wiring using 2 to 10 Vdc Control Signal
and Separate Transformers.
5 63-2516—07
ML6425, ML7425 SPRING RETURN ELECTRIC LINEAR VALVE ACTUATORS
L1
(HOT)
L2
1
1
WIRING
STRIP
F
+
–
T2
T1
O1
O2
TS
1
1
2
2
3
3
4
5
6
ML7425
T775
(WITH 2-10 VDC OUTPUT)
SINGLE
TRANSFORMER
40 VA 24 VAC
POWER SUPPLY. PROVIDE DISCONNECT MEANS
AND OVERLOAD PROTECTION AS REQUIRED.
M7895
SENSOR
L1
(HOT)
L2
1
1
WIRING
STRIP
F
+
–
T2
T1
O1
O2
TS
1
1
2
2
3
3
4
5
6
L1
(HOT)
L2
1
ML7425
T775
(WITH 4-20 MA OUTPUT)
DUAL
TRANSFORMERS
POWER SUPPLY. PROVIDE DISCONNECT MEANS AND
OVERLOAD PROTECTION AS REQUIRED.
M7896
500 OHM
RESISTOR
SENSOR
L1
(HOT)
L2
1
1
WIRING
STRIP
F
+
–
T2
T1
O1
O2
TS
1
1
2
2
3
3
4
5
6
ML7425
SENSOR
T775
(WITH 4-20 MA OUTPUT)
SINGLE
TRANSFORMER
40 VA 24 VAC
POWER SUPPLY. PROVIDE DISCONNECT MEANS
AND OVERLOAD PROTECTION AS REQUIRED.
M7897
500 OHM
RESISTOR
Fig. 11. ML7425 Wiring using 2 to 10 Vdc Control Signal
and a Common Transformer.
Fig. 12. ML7425 Wiring using 4 to 20 mA Control Signal
and Separate Transformers.
Fig. 13. ML7425 Wiring using 4 to 20 mA Control Signal
and a Common Transformer.
NOTE: 500 ohm resistor not shipped with product.
M6628
Fig. 14. Replacing Actuator Cover.
NOTE: 500 ohm resistor not shipped with product.
63-2516—07 6
ML6425, ML7425 SPRING RETURN ELECTRIC LINEAR VALVE ACTUATORS
CAUTION
W3
0%
W1
100%50%
W2
M33047
Fig. 15. Location of W1, W2, and W3 Selector Plugs.
Auxiliary Potentiometers
The 43191679 Auxiliary Potentiometers can be used as
feedback potentiometers and to provide remote indication of
the valve position. Refer to the Installation Instructions packed
with the potentiometers.
Auxiliary Switches
Equipment Damage Hazard.
Improper voltage will damage the auxiliary switch
beyond repair.
Use the 43191680 Dual Auxiliary Switch only with 24
Vac applications.
ML7425
Signal Input (+)
The analog input signal (+) range is set at the factory to 0 to 10
Vdc. Changing the position of the W2 selector plug sets the
range to 2 through 10 Vdc. Selector plugs W1, W2, and W3 are
positioned on the back side of the printed circuit board. Refer
to Fig. 15 for location of the selector plugs.
Signal Input Failure
Using the potentiometer, the actuator can be set to run to any
position in event of a signal failure (ML7420/ML7425 only).
ML6420 does not have any input signal failure jumpers or
potentiometers.
Output Signal Feedback (F)
An analog output signal (2 to 10 Vdc) that represents the actual
actuator stem position is available at terminal F. It can be used
for remote indication of the stem position. When the valve stem
is fully downward, the output signal is 10 Vdc.
When the valve stem is up, the output signal is 0 or 2 Vdc. The
output of the signal does not change when the action of the
actuator is reversed using W3. See Direction of Action.
Actuator Override
To override the control signal (for freeze protection or similar
applications), connect the 24 Vac common (T2) to either
terminal O1 or O2. Connecting to terminal O1 fully extends the
actuator stem. Connecting to O2 fully retracts the actuator
stem.
The control signal (+) is ignored when the override signal is
applied to Terminal O1 or O2. This override can be achieved
with a switch or a relay (See Fig. 16).
The 43191680 Dual Auxiliary Switch can be used on both the
ML6425 and ML7425 Electric Linear Valve Actuators.
Switching points are adjustable over the full length of actuator
stroke; for example, the switch can be used to switch pumps or
provide remote indication of any stroke position. Refer to the
Installation Instructions packed with the auxiliary switch.
OPERATION
In the actuator, the drive of a synchronous motor is converted
into the linear motion of the actuator stem by using a spur gear
transmission. A button retainer clip connects the actuator stem
to the valve stem.
An integrated spring package limits the stem force to a factory
adjusted value in either direction. Installed microswitches turn
off the actuator when the specified stem force is reached.
The ML6425, ML7425 Spring Return Valve Actuators provide a
safety valve position in the event of power failure. On power
failure, the ML6425A and ML7425A extend the actuator stem;
the ML6425B and ML7425B retract the actuator stem.
The actuators are shipped from the factory with a spring
handle retaining clip installed, so the actuator can be
connected to the valve without applying power. Remove this
clip after the actuator is installed. (Refer to the Installation
section.)
ML7425
WIRING
STRIP
F
+
–
T2
T1
O1
O2
TS
1
POWER SUPPLY. PROVIDE DISCONNECT MEANS AND
OVERLOAD PROTECTION AS REQUIRED.
2
2-10 Vdc FEEDBACK SIGNAL. SEE OUTPUT SIGNAL
FEEDBACK SECTION.
3
0-10Vdc OR 2-10 Vdc CONTROL SIGNAL. SEE SIGNAL
INPUT (+) SECTION.
SEE OVERRIDE SECTION FOR DETAILS ON
4
OVERRIDE OPERATION.
2
F
+
–
INPUT
(FEEDBACK)
OUTPUT
3
SP3T
OVERRIDE
SWITCH
4
1
L1
(HOT)
L2
M7906A
Fig. 16. Connections for Overriding Control Signal to Drive
ML7425 to a Specific Position.
7 63-2516—07
ML6425, ML7425 SPRING RETURN ELECTRIC LINEAR VALVE ACTUATORS
Direction of Action (ML7420/ML7425 only)
The direction of actuator action can be changed using the
pushbutton and LED, which is factory set so that the actuator
drives the valve stem down on increasing signal and draws it
CHECKOUT
The actuator can be checked out either directly or by using a
controller.
Direct Checkout
1. Mount the actuator for the required application; see
Installation section.
2. Check the valve position and make sure that 24 Vac is
correctly applied to the actuator.
3. Apply the power to the appropriate leadwires to move
the valve.
4. If the actuator does not move, make sure the actuator is
properly installed/wired.
5. If the actuator installation and wiring are both correct
and the actuator does not run, replace the actuator.
up on decreasing signal. When the valve stem is up, the
output signal from the feedback (F) function is 0 or 2 Vdc. The
output of the signal does not change when W3 is used to
reverse the action of the actuator (see Fig. 15).
Controller Checkout
1. Adjust the setpoint of the controller to call for opening
the valve. Observe the actuator.
2. If the valve is closed, it should begin to open.
3. If the valve remains closed, move the setpoint further
toward the open setting.
4. If the valve does not move, check for 24 Vac in the
actuator power input.
5. If 24 Vac is present and the actuator does not operate,
check the voltage across the controller leadwires to
determine if the device is miswired.
6. If the wiring is correct, 24 Vac is present on the power
input terminals, and the actuator does not run, replace
the actuator.
Automation and Control Solutions
Honeywell International Inc.
1985 Douglas Drive North
Golden Valley, MN 55422
customer.honeywell.com
® U.S. Registered Trademark
© 211 Honeywell International Inc.
63-2516—07 M.S. Rev. 07-11
Printed in United States
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