The ML7420A / ML7425A,B actuators are for modulating
control with controls providing an analog output of
0 to 10Vdc or 2 to 10Vdc. They operate Honeywell’s standard
valves in heating, ventilation and air conditioning (HVAC)
applications. The direction of movement is reversible by
means of an internal selector plug.
SPECIFICATIONS
Temperature Limits
Ambient operating limits -10 to +50°C
Ambient storage limits-40 to +70°C
Medium valve
temperatureMax. 150°C
Signals
Signal input voltagey =
R
Signal source output
resistance1kΩ max.
Position feedback signal x = 2 to 10Vdc
Load1mA max.
Safety
Protection classII in acc. with EN60730-1
Protection standardIP54 in acc. with EN60529
Flame retardant
housingV0 in acc. with UL94
(with metal cable gland)
0 to 10Vdc or 2 to10Vdc
= 100k
i
@ 5 to 95%rh
@ 5 to 95%rh
Ω
his product meets the re quirements of
EN0B-0624GE02 R0399
CE
ML7420A/ML7425A,B
Wiring
Wiring terminals1.5mm
Cable entryPG13.5. Two additional knock
Model Number ML7420A3006 ML7420A3014 ML7425A3005 ML7425B3004
Supply Voltage 24Vac +/-15% 50/60Hz
Power Consumption
Signal Input 0(2)Vdc Actuator stem retracted. Two way valve:”open”, three way valve port A-AB:”closed” *
Signal Input 10Vdc Actuator stem extended. Two way valve:”closed”, Three way valve port A-AB:”open” *
Stroke 20mm
Run Time @ 50Hz 1min 0.5min 1.8min
Close-off Force ≥ 600N
Spring Return Time
Spring Return Direction
* Factory setting; can be reversed by action selector plug W3
2
outs PG11 and PG13.5 for
auxiliary switch and
potentiometer accessories
5VA 7VA 12VA
OPERATION
Weight
non spring return type 1.3kg
spring return type2.4kg
The drive of a synchronous motor is converted into linear
motion of the actuator stem by using a spur gear
transmission. The actuator stem is connected with the valve
stem by a button keyed retainer connection.
An integrated spring package limits the stem force to a
factory adjusted value in either direction.
Installed microswitches switch off the actuator precisely
when the specified stem force is reached.
Manual Operation
Actuators without spring return are equipped with a manual
operator used in case of power failure. Manual operation is
only possible after the power supply is switched off or
disconnected.
To operate push the manual operator knob down and turn
clockwise to move the stem downward and counter-clockwise
to move the stem upward. If the actuator returns to automatic
control, the manual operator knob unlocks automatically.
On actuators with spring return the manual operator is
located under the cover.
Spring Return
The ML7425A,B spring return types provide a defined safety
position of the valve in case of power failure.
The spring return actuators are shipped from the factory with
a shipment stop (to lock the knob) in order to allow
connection of the stem button retainer to the valve stem
without power supply.
Electrical Installation
The actuators are delivered with a pre-installed cable gland
PG13.5 and two additional knock outs for PG11 and PG13.5.
Cable length/diameter for field mounting:
•
Max. 200m/1.5mm
100m/1.5mm
To avoid malfunction it is necessary to connect 24Vac
power and ground (see Fig. 2).
In case of replacement please note that the override
switch has been changed (see Fig. 2).
2
or
2
(ML7420A3014)
NOTE
CAUTION
NOTE
CAUTION
Input Signal Failure
By means of selector plug W1* the actuator can be selected
such, that in case of a signal input failure,(e.g. a broken wire)
the actuator will run to one of the three positions:
0%:actuator stem position for 0(2)Vdc
50%:actuator stem in central position
100%:actuator stem position for 10Vdc
W1 is set by the factory to 50%.
Input Signal Range
The range of the analog input signal Y can be changed by
changing the position of selector plug W2*
EN0B-0624GE02 R03992
Action
The direction of action can be changed by repositioning of
selector plug W3*. It is set by the factory such that the stem
extends at increasing signal and retracts at decreasing
signal.
NOTE
CAUTION
*Jumper plugs W1, W2 and W3 are accessible after the
cover has been removed. They are located on the rear
side of the protection sheet of the printed circuit board
(see EN1C-0073 and EN1C-0074).
Output Signal ”POSITION”
An analog output signal 2 to 10Vdc ”POSITION” is available
which represents the actual actuator position. It can be used
for remote indication.
When the actuator stem is extended the output signal is
10Vdc.
Accessories
Auxiliary switches
The actuators can be equipped on site with an auxiliary
switch unit with two switches. Their switching points are
adjustable over the full length of the actuator stroke. The
switches can be used to switch pumps or provide remote
indication of any stroke position.
A cable gland PG13.5 is delivered with the unit.
Part number: 43191680-005
ML7420A/ML7425A,B
Auxiliary potentiometer
Auxiliary potentiometers are available for mounting on site.
They can be used as feedback potentiometer and or to
provide remote indication to the valve position.
A cable gland PG13.5 is delivered with the unit.
Part number: 43191679-011 (10kΩ)
Part number: 43191679-012 (220Ω)