ML745A,B Spring Return Electric Linear Valve Actuator EATURES Quick and easy installation. No separate linkage required. PRODUCT DATA ML745A extends actuator stem on power failure; ML745B retracts actuator stem on power failure. Conduit connector is standard. No adjustments required. True spring return on power failure. Accurate valve positioning. Low power consumption. High close-off ratings. APPLICATION The ML745A,B Spring Return Electric Linear Valve Actuators are modulating control actuators used with controls that provide an analog output of 0 to 0 Vdc or to 0 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. orce-limiting end switches. 0 to 0 Vdc or to 0 Vdc signal input. Position feedback signal. Direct/reverse action. ail-safe position selection. Synchronous motor. Corrosion resistant design. Maintenance free. Contents Application... eatures... Specifications... Ordering Information... Installation... Operation... 7 Checkout... 8 U.S. Registered Trademark Copyright 996 Honeywell Inc. All Rights Reserved X-XX UL 6-58-
ML745A,B SPRING RETURN ELECTRIC LINEAR VALVE ACTUATOR SPECIICATIONS Models: Model Description Spring Return Action ML745A Electric Linear Valve Actuator Extends actuator stem on power failure ML745B Retracts actuator stem on power failure Electrical Ratings: Power Input: 4 Vac (0%, -5%), 60 Hz Power Consumption: VA maximum at 4 Vac Signal Inputs: 0 to 0 Vdc or to 0 Vdc Signal Source Output Resistance: K ohm maximum Load: ma maximum Stem orce: 5 lbf (600N) Actuator Stroke: /4 in. (0 mm) Actuator Run Time at 60 Hz: ML745A: 90 seconds ML745B: 90 seconds Spring Return Time: seconds Ambient Temperature Range: 4 to (-0 C to 50 C) Storage Temperature Range: -40 to 58 (-40 C to 70 C) Maximum Valve Medium Temperature: 00 (50 C) Humidity: 5 to 95 percent relative humidity, noncondensing Close-off Pressure Ratings: See Tables and. Protection Standard: IP54 Insulation: Class II (4 Vac) Approvals: UL94-5V lame Retardant Meets CE standards Cable Entry: Conduit connector and one knockout are standard on actuator case. Actuator Material: Cover: ABS-R plastic Yoke and Base: Diecast aluminum Weight: 5. lb (. kg) Dimensions: See ig.. Accessories: 49679- Single Auxiliary 0 ohm Potentiometer for ML745A/B 49679- Single Auxiliary 0K ohm Potentiometer for ML745A/B 49680-05 Dual Auxiliary Switch for ML745A,B (for 4 Vac use only) 496000-0 High Temperature Kit. Includes /4 in. and /8 in. stem extenders. The kit increases the temperature range to 48 (0 C). ORDERING INORMATION 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:. Your local Home and Building Control Sales Office (check white pages of your phone directory).. Home and Building Control Customer Logistics Honeywell Inc., 885 Douglas Drive North Minneapolis, Minnesota 554-486 (6) 95-000 In Canada Honeywell Limited/Honeywell Limitée, 55 Gordon Baker Road, North York, Ontario MH C9. International Sales and Service Offices in all principal cities of the world. Manufacturing in Australia, Canada, inland, rance, Germany, Japan, Mexico, Netherlands, Spain, Taiwan, United Kingdom, U.S.A. 6-58
ML745A,B SPRING RETURN ELECTRIC LINEAR VALVE ACTUATOR Table. Close-off ratings in psi for ML745A,B Electric Linear Valve Actuators and V50, V50 Valves. Valve Type / in. /4 in. in. -/4 in. -/ in. in. -/ in. in. V50A lange N/A N/A N/A N/A N/A N/A 8 6 V50 Screw 50 50 50 45 86 49 8 6 V50G Screw 50 50 50 4 77 49 8 6 V50B lange N/A N/A N/A N/A N/A N/A 4 V50C lange N/A N/A N/A N/A N/A N/A 4 V50 Screw 50 50 50 6 77 49 N/A N/A / () PT YOKE DIAMETER -/8 (5) -/6 (67) 5-5/5 6-5/6 (5) x (6) 7-5/8 (9) -/4 (84) 4-5/6 (64) M789 ig.. Approximate dimensions of ML745A,B Electric Linear Valve Actuator in in. (mm). Table. Close-off ratings in psi for ML745A,B Electric Valve Actuators and V50,; V60,; V450,; V460, Valves. Close-Off Rating psi (kpa) a Valve Model Valve Size in in. 5 lbf (600 N) V50, V5, -/ (45) V60, V6, 4 (97) V450, V45, 4 V460, V46 5 a Represents maximum pressure difference between the outlet and either of the two inlets. INSTALLATION 6 When Installing this Product.... Read instructions carefully. ailure to follow them could damage the product or cause a hazardous condition.. Check ratings and description given in the specifications to make sure the product is suitable for your application.. Installer must be a trained, experienced service technician. 4. After installation is complete, check out product operation as provided in these instructions. Disconnect power before installation to prevent electrical shock or equipment damage. Location Install the actuator in a location that allows enough clearance for mounting accessories and for servicing. See ig.. Do not install the actuator in a position below horizontal to minimize risk of damage to actuator in the event of condensation or a valve gland leak. Mounting Place the actuator on the valve with the U-bolt around the valve collar. See ig.. 6-58
ML745A,B SPRING RETURN ELECTRIC LINEAR VALVE ACTUATOR Release the stem button retaining clip to secure the stem button. Check to make certain the stem button is secured by the retaining clip. Remove the cover from the actuator, using a Phillips or crosspoint screwdriver. See ig. 4. The manual spring handle is under tension and can turn quickly when lifted, pinching fingers between the handle and plastic casing, which can result in injury. Maintain handle orientation while lifting and remove fingers quickly when releasing. Remove manual spring handle retaining clip and lift and release the handle. See ig. 5. The easiest way to safely perform this operation is to: remove the retaining clip, then wedge a small, flat-bladed screwdriver under the manual spring handle at the point marked in ig. 5 and pry up the handle. M66 ig.. Attaching the actuator to the valve collar. 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. Push aside the stem button retaining clip and hold. See ig.. ig. 4. Removing ML745 cover. M667 ig.. Securing ML745 to valve. M66 Lift the valve stem until the head of the valve stem button is inside the large slot of the stem button retaining clip on the actuator. M669 ig. 5. Removing spring retaining clip and releasing manual spring handle. 6-58 4
ML745A,B SPRING RETURN ELECTRIC LINEAR VALVE ACTUATOR Wiring Disconnect power supply before starting wiring to prevent electrical shock or equipment damage. ML745 T INPUT (EEDBACK) OUTPUT All wiring must comply with local electrical codes, ordinances and regulations. Voltage and frequency of the transformer used with the ML745 must correspond with the characteristics of the power supply and those of the actuator. See ig. 7 through for typical wiring hookups. T O O eed power and control wires through the conduit connector located on the bottom of the actuator case. See ig. 6. L L -0 Vdc EEDBACK SIGNAL. SEE OUTPUT SIGNAL EEDBACK SECTION. 0-0 Vdc OR -0 Vdc CONTROL SIGNAL (SEE W). C886A ig. 7. ML745 wiring diagram using feedback output from another controller with one transformer. ML745 4 5 6 SENSOR ig. 6. Connecting power and control wiring to ML745. If conduit connector is to be removed, use a wrench to support the metal connector when tightening or removing the conduit pipe. Using the wiring diagrams in ig. 7 through, connect power and control wires to the ML745. Make sure that all wiring is correct. When wiring is complete, replace the cover on the ML745. See ig.. NOTE: Make the selector plug changes, if required, before replacing the cover. See ig.. Apply power and control signals to the ML745. M660 T T O O T775 (WITH -0 VDC OUTPUT) L L L L DUAL TRANSORMERS M7894 ig. 8. ML745 wiring diagram using a to 0 Vdc output control (e.g., T775) with two transformers. ML745 4 5 6 SENSOR T T O O T775 (WITH -0 VDC OUTPUT) L L SINGLE TRANSORMER 40 VA 4 VAC M7895 ig. 9. ML745 wiring diagram using a to 0 Vdc output control (e.g., T775) with one transformer. 5 6-58
ML745A,B SPRING RETURN ELECTRIC LINEAR VALVE ACTUATOR ML745 4 5 6 SENSOR T T O O 500 OHM RESISTOR T775 (WITH 4-0 MA OUTPUT) L L L L DUAL TRANSORMERS M7896 ig. 0. ML745 wiring diagram using a 4 to 0 ma output control (e.g., T775) with two transformers. ML745 4 5 6 SENSOR M668 T T O O T775 (WITH -0 VDC OUTPUT) L L L L DUAL TRANSORMERS M7894 ig.. ML745 wiring diagram using a 4 to 0 ma output control (e.g., T775) with one transformer. ig.. Replacing cover on ML745. Auxiliary Potentiometers The 49679 Auxiliary Potentiometers can be used as feedback potentiometers and to provide remote indication of the valve position. See the installation instructions packed with the potentiometers. Auxiliary Switches The 49680 Dual Auxiliary Switch can be used on both the ML745A and ML745B 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. Use the 49680 Dual Auxiliary Switch only with 4 Vac applications. 6-58 6
ML745A,B SPRING RETURN ELECTRIC LINEAR VALVE ACTUATOR OPERATION General In the ML745, 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 ML745A,B Spring Return Valve Actuators provide a safety valve position in event of power failure. On power failure, the ML745A returns the stem to the bottom position. On power failure, ML745B returns the stem fully upward. The ML745 actuators are shipped from the factory with a spring handle retaining clip installed, so that the actuator can be connected to the valve without applying power. This clip is removed after the actuator is installed on the valve. See Installation section. Output Signal eedback () An analog output signal ( to 0 Vdc) that represents the actual actuator stem position is available at Terminal. It can be used for remote indication of the stem position. When the actuator stem is fully extended, the output signal is 0 Vdc. When the actuator stem is up, the output signal is 0 or Vdc. The output of the signal does not change when the action of the actuator is reversed using W. See Direction of Action. Actuator Override The converter output signal override function can be used in freeze protection or similar applications. It forces the actuator to a specific position, overriding the control signal. To exercise this function, disconnect the 4 Vac common from the actuator ( or T) and connect it to either Terminal O or O. Connecting to Terminal O fully extends the actuator stem. Connecting to O fully retracts the actuator stem. The control signal () is ignored when the override signal is applied to Terminal O or O. This override can be achieved with a switch or a relay. See ig. 4. Signal Input () The analog input signal () range is set at the factory to 0 to 0 Vdc. Changing the position of the W selector plug sets the range to through 0 Vdc. Selector plugs W, W, and W are positioned on the back side of the internal label holder. See ig. for location of the selector plugs. W W W ML745 T T O O INPUT (EEDBACK) OUTPUT SPT OVERRIDE SWITCH 4 0V 0V 0% 50% 00%... 0V 0... 0V L L -0 Vdc EEDBACK SIGNAL. SEE OUTPUT SIGNAL EEDBACK SECTION. 0-0Vdc OR -0 Vdc CONTROL SIGNAL (SEE W). M66 ig.. Location of W, W and W selector plugs. Signal Input ailure Using selector plug W, the actuator can be set to run to one of three positions in event of a signal failure: 0% Actuator position corresponds with 0 or Vdc signal 50% Actuator stem in mid-position 00% Actuator position according to 0 Vdc signal W is factory set at the mid-position. 4 SEE OVERRIDE SECTION OR DETAILS ON OVERRIDE OPERATION. M7906 ig. 4. Connections for overriding control signal to drive actuator to a specific position. Direction of Action The direction of the actuator action can be changed by repositioning selector plug W, which is factory set so that the stem extends on increasing signal and retracts on decreasing signal. When the actuator stem is up, the output signal from the feedback () function is 0 or Vdc. The output of the signal does not change when W is used to reverse the action of the actuator. See ig.. 7 6-58
ML745A,B SPRING RETURN ELECTRIC LINEAR VALVE ACTUATOR CHECKOUT The ML745 Electric Linear Valve Actuator can be checked out either directly or by using a controller. Direct Checkout Mount the actuator for the required application (see Installation section). Check the valve position and make sure that 4 Vac is correctly applied to the actuator. Apply the control signal to the appropriate leadwires to move the valve in the opposite direction. If the actuator does not move, make sure the actuator is properly installed/wired. If the actuator installation and wiring are both correct and the actuator does not run, replace the actuator. Controller Checkout Adjust the setpoint of the controller to call for opening the valve. Observe the actuator. If the valve is closed, it should begin to open. If the valve remains closed, move the setpoint further toward the open setting. If the valve does not move, check for 4 Vac in the actuator power input. If 4 Vac is present and the actuator does not operate, check the voltage across the controller leadwires to determine if the device is miswired. If the wiring is correct, 4 Vac is present on the power input terminals, and the actuator does not run, replace the actuator. Home and Building Control Honeywell Inc. Honeywell Plaza P.O. Box 54 Minneapolis MN 55408-054 Honeywell Latin American Division Miami Lakes Headquarters 4505 Commerce Way Suite 500 Miami Lakes L 06 Home and Building Control Honeywell Limited-Honeywell Limitée 55 Gordon Baker Road North York, Ontario MH C9 Honeywell Europe S.A. Avenue du Bourget B-40 Brussels Belgium Honeywell Asia Pacific Inc. Room -5 Sun Hung Kai Centre No. 0 Harbour Road Wanchai Hong Kong Printed on recycled paper containing at 6-58 C.H. Rev. 0-96 Printed in U.S.A. least 0% post-consumer 8 paper fibers. Helping You Control Your World