HONEYWELL ML7984A4009 Valve Actuator

Honeywell ML7984A4009 valve actuator is a self-adjusting, self-contained, motorised actuator that controls the opening and closing of a valve. It provides the necessary force to move the valve to the desired position. This Honeywell butterfly valve actuator finds application in various oil & gas, water treatment, power generation, chemical processing, HVAC and manufacturing processes. It easily attaches to Honeywell V5011A1858/U 2-way globe valve or Honeywell V5013C1043/U 3-way globe valve for linear stem operation.

Working Mechanism:

• Inside Honeywell ML7984A4009 valve actuator, there are circuits that use power to control its movement.
• The actuator's sensing circuits are configured based on the settings of switches.
• It compares the control signal with the feedback voltage from the actuator to see if they match.
• If they match, it means everything is balanced, and the motor and shaft stay still.
• As long as the controlled medium remains stable, the actuator stays in its current position.
• When there is a change in the medium being controlled, the actuator adjusts its position accordingly.
• Simultaneously, a component called the feedback potentiometer ensures everything remains balanced.
• The potentiometer moves the valve until it reaches the desired position.
• Once the valve is in the correct position, and everything is stable, the motor automatically stops to prevent any issues.

Features:

• Honeywell ML7984A4009 valve actuator supports multiple valves using a single transformer power supply.
• It is small in size and ideal for installation in confined spaces.
• This Honeywell butterfly valve actuator's linkage self-adjusts to valve strokes of up to 19 mm (3/4 inches).
• Its electronic current sensing provides internal protection and a positive full closure force.

Compatible Accessories:

• Honeywell 272630A auxiliary switch assembly (1-SPDT) and Honeywell 272630B auxiliary switch assembly (2-SPDT) are suitable for seamless electrical connections.
• Honeywell 40003793-003 Mounting Hardware Bag Assembly: This 8-piece assembly kit is useful for the initial mounting of the brand's valve actuator.
• Honeywell 272822 Resistor Kit: This kit helps users connect the butterfly valve actuator with multiple Series 90 valves (quarter-turn valves).

Frequently Asked Questions:

Q. What is the difference between single-acting and double-acting actuators?

A. Single-acting actuators use air pressure to open or close a valve, whereas double-acting actuators can do both.

Q. How to mount Honeywell ML7984 valve actuator?

A.

• It is advisable to mount the ML7984 valve actuator above the valve body.
• This positioning helps minimise the risk of damage to the valve actuator in case of condensation or leakage from the valve gland.
• Begin by removing the stem button from the valve stem.
• Ensure to save the set screw located inside the stem button for later use.
• The button itself is not required for the mounting process.
• Slide the position indicator, which could be a plastic disk or rubber O-ring, over the valve stem.
• The indicator will automatically align itself to the marking on the yoke after completing one full operating cycle.

Q. How to assemble Honeywell butterfly valve actuator?

A.

• Begin by sliding the yoke over the valve bonnet.
• Thread the ML7984 drive shaft onto the valve stem completely by rotating the valve actuator clockwise.
• Ensure that the drive shaft is fully attached with no threads showing.
• Use a pin or wrench to prevent the valve stem from turning while tightening.
• Avoid damaging the threads or any other parts of the stem while tightening.
• Orient the conduit hole in the most suitable direction, then tighten the locknuts on the U-bolt securely.
• Loosen the two screws located on the top of the valve actuator to remove the plastic cover.
• These screws are captive, so rotate them three complete revolutions to release the cover.
• Once removed, drop either a slot-headed or Allen Hex type of set screw (both included in the plastic bag) into the top of the shaft, with the slotted or hexed side facing up.
• Depending on the type of set screw used, tighten it using a 5mm (3/16 inch) slotted screwdriver or a 1/8x 6 Allen wrench. This will lock the valve stem in place.