Honeywell ML7421A, ML7421B SPECIFICATION DATA

ML7421A,B

Electric Linear Valve Actuators

GENERAL

These actuators enable modulating control in conjunction with controls providing an analog output. The direction of movement is reversible by means of an internal selector plug.

They operate Honeywell’s standard valves in heating, ventilation, and air conditioning (HVAC) applications.

SPECIFICATION DATA

FEATURES

• Quick and easy installation

• No separate linkage required

• No adjustments

• Force-limiting end switches

• Manual operator

• Synchronous motor

• Corrosion-resistant design

• Selectable 0...10 Vdc or 2...10 Vdc/

0...20 mA or 4...20 mA input signal

• Position feedback signal

• Direct or reverse-acting adjustable

• Selectable stroke position on signal failure

• Maintenance-free

SPECIFICATIONS

Temperature Limits

Ambient operating limits -10...+50 °C @ 5...95%rh Ambient storage limits -40...+70 °C @ 5...95%rh Medium valve temperature Max. +150 °C (220 °C with High-Temperature Kit)

Safety

Protection class III according to EN60730-1 Protection standard IP54 according to EN60529 Flame retardant housing V0 according to UL94, with metal cable gland

Noise level ≤45dB(A) Signals

Input range Y = 0(2)...10 Vdc, 0(4)...20 mA Input impedance for voltage R for mA R

Signal source output impedance Max. 1 kΩ Output voltage range Position: 2...10 Vdc Output load Max. 1 mA

Wiring

Wiring terminals 1.5 mm2 Cable entry M20x1.5 and knock-out for PG11

Material

Cover ABS-FR Yoke and Base Aluminum diecast

Weight 2.0 kg Dimensions see Fig. 3 and Fig. 4

= 100 kΩ

= 500 Ω

ML7421A,B ELECTRIC LINEAR VALVE ACTUATORS

model number ML7421A3004 ML7421B3003

supply voltage

power consumption

signal input 0(2) Vdc

signal input 10 Vdc

stroke

run-time at 50 Hz

nominal stem force

Actuator stem retracted. Two-way valve: open, three-way valve port A - AB: closed

Actuator stem extended. Two-way valve: closed, three-way valve port A - AB: open

OPERATION

General

The drive of a synchronous motor is converted into linear motion of the actuator stem by using a worm gear transmission.

The actuator stem is connected with the valve stem by a button keyed retainer connection.

Via installed microswitches, the internal force sensor switches off the actuator precisely when the nominal stem force is reached.

If used as a replacement of an already-installed actuator M7421A,B, the following issue is to observe:

• Permanent power supply (see section "Electrical Installation")

Manual Operation

The actuators are equipped with a manual operator used in case of power failure. Manual operation is possible only after the power supply has been switched off or disconnected.

To operate, push the manual operator knob down and turn clockwise to move the stem upward and counter-clockwise to move the stem downward. If the actuator returns to automatic control, the manual operator knob unlocks automatically.

24 Vac (+10%/-15%); 50/60 Hz

14 VA (50 Hz) / 16 VA (60 Hz)

20 mm 38 mm

1.9 min 3.5 min

1800 N

Input Signal Range

The range of the analog input signal Y (0...10 Vdc / 0...20 mA or 2...10 Vdc / 4...20 mA) can be selected by changing the position of jumper plug W2 (Fig. 1.). The factory set is at

0...10 Vdc.

Direction of Action

The direction of action (direct or reverse) can be selected by changing the position of jumper plug W3 (Fig. 1.). The factory set is: stem extends at increasing signal (direct acting).

NOTE: Jumper plugs W1, W2, W3, and W4 are accessible

after the cover has been removed. They are located on top side of the printed circuit board (see Fig. 2).

NOTE: Manual operation allows a very high closing force

capable of jamming the actuator spindle and exceeding the rating of the force switches, so that the motor cannot move. Therefore, after a manually close-off operation, it is necessary to release the spindle one turn by turning the manual operator knob, thus ensuring that the manual operator will automatically disengage on power resumption.

Fig. 1. Location of jumper plugs W1, W2, W3, W4

Electrical Installation

24 V∼ and 24 V⊥ (see Fig. 3.) must be applied under all operating conditions.

Cable length/diameter for field mounting:

• Max. 200 m / 1.5 mm2

Input Signal

The Vdc- or mA-input signal is selected by shifting jumper plug W4 (see Fig. 2). The factory setting of W4 is "Vdc". No external resistor for mA-input signal is necessary.

EN0B-0416GE51 R0409 2

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