Honeywell ML7421A1032 Operation manual

PRODUCTDATA
® U.S. Registered Trademark
Copyright © 1999 Honeywell Inc. • All Rights Reserved
ML7421A,B
Electric Linear Valve Actuator
GENERAL
The ML7421A,B Electric Linear Valve Actuators for
modulating controlare equipped with a stepper motor for
exact positioning. The direction of movement is reversible by
means of an internal selector plug. These actuators operate
standard Honeywell valves in heating, ventilating, and air
conditioning (HVAC) applications.
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FEATURES
• Quick and easy installation.
• No separate linkage required.
• 3/4 in. (20 mm) stroke on ML7421A;
1-1/2 in. (38 mm) stroke on ML7421B.
• No adjustments required.
• Accurate valve positioning.
• Selectable 0(2) to 10 Vdc/0(4) to 20 mA input signal.
• Position feedback.
• Force-limiting end switches.
• Manual operator.
• Direct or reverse acting.
• Synchronous motor.
• Corrosion resistant design.
• Maintenance free.
• Conduit connector knockout.
Contents
General............................................................................ 1
Features .......................................................................... 1
Specifications .................................................................. 2
Installation ....................................................................... 3
Operation ......................................................................... 5
Checkout ......................................................................... 6
Ordering Information ....................................................... 7

ML7421A,B ELECTRIC LINEAR VALVE ACTUATOR
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Table 1. Close-off Ratings in psi for ML7421A,B Electric Linear Valve Actuators and V5011, V5013 Valves
aFor use only with ML7421B Actuator.
Model No. Stroke in
in. (mm) Run Time in s at 60 Hz
ML7421A1032 3/4 (20) 95
ML7421B1023 1-1/2 (38) 175
Electrical Ratings:
Power Input: 24 Vac (+10%/-15%), 60 Hz
Power Consumption: 12VA max. at 24Vac
Signal Source Output Resistance:
1 kOhm max.
Load:
1 mA max.
SignalInput:
0 to 10 Vdc or 2 to 10 Vdc
Stem Force:
405 lbf (1800N)
Ambient Temperature Range:
14°F to 122°F (-10°C to +50°C)
Storage Temperature Range:
-40°F to 158°F (-40°C to +50°C)
Humidity:
5 to 95% relative humidity, non condensing.
Close-off Pressure Ratings:
See Tables 1. and 2.
Protection Standard:
IP54
Insulation:
Class II (24 Vac)
Approvals:
UL94-5V Flame retardant.
Meets CE requirements.
Cable Entry:
Two knockout holes for 1/2 in. and 3/4 in. conduit standard
on actuator case.
Actuator Material:
Cover: ABS plastic
Yoke and Base: Diecast aluminium
Weight:
5.1 lb (2.3 kg)
Dimensions:
See Fig. 1.
Accessories:
43191680-102 Dual Auxiliary Switch for ML7421A,B
( for 24 Vac use only).
43196000-101 High Temperature Kit. Includes 1/4 in. and
3/8 in. stem extenders. The kit increases the temperature
range to 428°F (220°C).
43196000-102 High Temperature Kit (2...3 in. valves).
Includes1/4 in. and 3/8 in. stem extenders.
The kit increases the temperature range to
428°F (220°C).
SPECIFICATIONS
Models:
Valve Type 1/2 in. 3/4 in. 1 in. 1-1/4 in. 1-1/2 in. 2 in. 2-1/2 in. 3 in. 4 in. a5 in. a6 in. a
V5011A Flange N/A N/A N/A N/A N/A N/A 77 53 29 18 12
V5011B Flange N/A N/A N/A N/A N/A N/A N/A N/A 29 18 12
V5011F Screw 150 150 150 150 150 150 100 61 N/A N/A N/A
V5011G Screw 150 150 150 150 150 150 100 61 N/A N/A N/A
V5013B Flange N/A N/A N/A N/A N/A N/A 77 53 29 18 12
V5013C Flange N/A N/A N/A N/A N/A N/A 77 53 29 18 12
V5013F Screw 150 150 150 150 150 150 N/A N/A N/A N/A N/A

ML7421A,B ELECTRIC LINEAR VALVE ACTUATOR
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Location
Install the actuator in a location that allows enough
clearance for mounting accessories and for servicing. See
Fig. 1.
CAUTION
Do not install the actuator in a position below
horizontal to minimize the risk of damage to the
actuator in the event of condensation or a valve
gland leak.
Mounting
NOTE: Check for valve stem button adjustment dimension.
1. Attach the actuator to the valve collar and tighten the
set screws with a 5/32 in. (4mm) hex wrench.
IMPORTANT:
When tightening the set screws, first tighten the
right set screw. See Fig. 2.
Fig. 2. Attaching actuator to valve collar.
Fig. 1. Approximate dimensions of ML7421A,B Electric Linear Valve Actuator in in. (mm).
Valve Model Valve Size in in. Close-Off
Rating psi (kPa)a
404 lbf (1800N)
V3350, V3351, 2-1/2 63 (434)
V3360, V3361, 3 45 (310)
V3450, V3451, 4b25 (172)
V3460, V3461 5b16 (110)
6b11 (76)
INSTALLATION
When Installing this Product...
1. Read these instructions carefully. Failure to follow them
could damage the product or cause a hazardous
condition.
2. Check the ratings given in the instructions and on the
product 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.
CAUTION
Disconnect power before installation to prevent
electrical shock or equipment damage.
Table 2. Close-off Ratings in psi for ML7421A,B and
V3350,1; V3360,1; V3451,1; V3461,1 Valves.
aRepresents max. pressure difference between outlet and inlet.
bFor use only with ML7421B Actuators.

ML7421A,B ELECTRIC LINEAR VALVE ACTUATOR
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2. Push the stem button retaining clip and hold.
See Fig. 3.
Fig. 3. Attaching actuator to valve stem.
3. Lift the valve stem until the head of the valve stem
button is inside the large slot of the stem button
retaining clip.
4. Release the stem button retaining clip to secure the
stem button.
5. Check to ensure that the retaining clip holds the
stem button in place.
6. Pull of the manual operation knob, loosen the cover
screws, and remove the actuator cover.
1. Feed the power and control wires through the opening
on the bottom of the actuator case.
2. Using the wiring diagrams in Fig. 4 through 6, connect
the power and control wires to the ML7421. Make sure
that all wiring is correct.
3. When wiring and checkout are complete, replace the
cover, tighten the cover screws, and replace the
manual operator knob, see Fig. 7.
4. Apply cover and control signals to the ML7421.
Fig. 4. ML7421 typical wiring diagram.
Fig. 5. ML7421 wiring diagram using a 0(2) to 10Vdc
output control (e.g. T7759) with two transformers.
Fig. 6. ML7421 wiring diagram using a 0(2) to 10Vdc
output control (e.g. T7759) with one transformer.
Wiring
CAUTION
Disconnect the power supply before wiring to prevent
electrical shock or equipment damage.
All wiring must comply with local electrical codes,
ordinances and regulations. Voltage and frequency of the
transformer used with the ML7421 must correspond with
the characteristics of the power supply and those of the
actuator.

ML7421A,B ELECTRIC LINEAR VALVE ACTUATOR
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OPERATION
General
In the ML7421, the drive of a synchronous motor is
converted into the linear motion of the actuator stem by
using a worm gear transmission. A button retainer
clip connects the actuator stem to the valve stem.
The internal force sensor, using installed microswitches,
turns off the actuator when the specified stem force is
reached.
Manual Operation
The ML7421 is equipped with a manual operator knob (see
Fig. 7) to open or close the valve in the event of power
failure. Turn off or diconnect the power supply before
manuallly operating the ML7421.
To operate, push down the manual operator knob and turn
the knob counterclockwise to move the stem downward or
clockwise to move the stem upward. If the actuator is
returned to automatic control, the manual operator knob
unlocks automatically.
NOTE: If the manual operator knob is not pushed in while
turned, it turns only a short distance before it
automatically disengages without power resumption.
IMPORTANT:
Manual operation allows a very high closing force
that can jam the actuator spindle, exceeding the
rating of the force switches, and stopping the
motor.
After a manual valve close-off operation, release
the spindle one turn by turning the the manual
operator knob so the manual operator
automatically disengages on power resumption.
Auxiliaryswitches
The 43191680 Dual Auxiliary Switch can be used on both
the
ML7421A and ML7421B Electric Linear Valve Actuators.
Switching points are adjustable over the full length of the
actuator stroke; for example, the switch can be used to
switch pumps or to provide remote indication of any stroke
position. See the Installation Instructions packed with the
auxiliary switch.
IMPORTANT:
Use the 43191680 Dual Auxiliary Switch only with
24 Vac applications.
ACCESSORIES
Fig. 7. ML7421A,B manual operator knob.
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.
Changing the W4 position to mA (see Fig. 8.) the ranges are
0(4) to 20 mA. Selector plugs W1, W2, W3 and W4 are
positioned on the back side of the PCB protection sheet.
See Fig. 8 for location of the selector plugs.
2...10V
4...20mA
W2
0...10V
0...20mA
10V
20mA
W3
10V
20mA mA
W4
V
W1 (W4 )
V
Fig. 8. Location of selector plugs W1, W2, W3 and W4.
Signal Input Failure
Using selector plug W1, the actuator can be set to run to
one of three positions in event of a signal failure:
1. 0% — Actuator position corresponds with 0 or 2 Vdc
signal
2. 50% — Actuator stem in mid-position
3. 100% — Actuator position according to 10 Vdc signal
NOTE: W1 is factory set at 50% .
If W4 is set to mA-position, the actuator runs
always to 0% .

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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 actuator stem is fully extended, the output signal
is 10 Vdc.
The output of the signal does not change when the action of
the actuator is reversed using W3 or W4, which is set to
mA-position, see Direction of Action.
Actuator Override
The converter output signal override position can be used in
freeze protection or similar applications. it forces the
actuator into an end position, overriding the control signal.
To exercise this function, connect the 24 Vac common (or
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 relay, see Fig. 9.
Fig. 9. Connection for overriding control sigal to
drive actuator to specific position.
CHECKOUT
The ML7421 Electric Linear Valve Actuator can be checked
out either directly or using a controller.
1. Mount the actuator for the required application.
2. Check the valve position and make sure that 24 Vac is
correctly applied to the actuator.
3. Apply the control signal to the appropriate leadwires
to move the valve in the required direction.
4. If the actuator does not move, make sure the actuator
is properly installed.
5. If the actuator is correctly installed and does not run,
replace the actuator.
Direct Checkout
Controller Checkout
1. Adjust the setpoint of the controller to call for opening
or closing 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
towards 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,
reverse 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.
Direction of Action
The direction of the actuator action can be changed by
repositioning selector plug W3, which is factory set so that
the stem extends on increasing signal and retracts on
decreasing signal. When the actuator stem is fully extended
the output signal from feedback (F) function is 2 Vdc.

ML7421A,B ELECTRIC LINEAR VALVE ACTUATOR
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ORDERINGINFORMATION
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 Home and Building Control Sales Office (check white pages of your phone directory).
2. Home and Building Control Customer Logistics
Honeywell Inc., 1885 Douglas Drive North
Minneapolis, Minnesota 55422-4386 [phone]
In Canada—Honeywell Limited/Honeywell Limitée, 155 Gordon Baker Road, North York, Ontario M2H 3N7.
International Sales and Service Offices in all principal cities of the world. Manufacturing in Australia, Canada, Finland, France,
Germany, Japan, Mexico, Netherlands, Spain, Taiwan, United Kingdom, U.S.A.

ML7421A,B ELECTRIC LINEAR VALVE ACTUATOR
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63-2517-2Printed in U.S.A. 7-99