STP SERIES Install, Operation, and Maintenance Manual
SECTION 3: OPERATION AND CONTROLS
Page
24
of
97
Diversified Heat Transfer, Inc.
•
439 Main Road
•
Towaco, New Jersey 07082
Rev-1
09/11/2019 PHONE: 800-221-1522
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WEBSITE: www.dhtnet.com
STP Manual
path A → AB with a 0% stroke control signal (4 mA). In this case, the valve can be recalibrated
as follows:
•
Use a pin or paper clip to push the button in opening (A) in the terminal housing.
•
During calibration, the LED light (B) in the electronics module will flash green for
approximately 10 seconds. The valve will be briefly closed and fully opened.
CAUTION!
This valve is suitable for straight-through normally closed 2-way application with STP units.
FIGURE 3-5: Control Valve Hydraulic Circuits Application Examples
3.5.3 Auto and Manual Control of Control Valve
The Control Valve Automatic and Manual control modes can be selected using the knob shown
in Figure 3-6.
FIGURE 3-6: Selecting AUTO or MANUAL Control
3.5.3.1 AUTO Control
The control signal is converted by the microprocessor in the electronics module into an output
signal that generates a magnetic field in the core. This causes the only moving part, the
armature, to change its position in accordance with the interacting forces (magnetic field,
counter-spring, hydraulics, and so on). The armature responds rapidly to any change in signal,
transferring the corresponding movement directly to the control disc, enabling fast changes in
load to be corrected quickly and accurately. The valve position is measured continuously. The
positioning controller ensures an exactly proportional relationship between the control signal
and the valve stroke.
A
= Mixing circuit
B
= Mixing circuit with bypass
(underfloor heating)
C
= Injection circuit
D
= Diverting circuit
E
= Injection circuit with straight-
through valve