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Wiring; Operation - Honeywell VC7900 Series Product Data

Modulating control valves
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VC7900 - WIRING, OPERATIONS
NOTE: The actuator can also be installed at right angles to the
valve body but in this position the latch mechanism will
not engage.
5. Install the new actuator by reversing the process in (4).
6. Reconnect leadwires or Molex
7. Restore power, and check-out operation.
MANUAL OPENER
The manual opener can be manipulated only when in the up
position. The "A" port can be manually opened by firmly pushing
the white manual lever down to midway and in. In this position both
the "A" and "B" ports are open, and with auxiliary switch models the
switch is closed. This "manual open" position may be used for
filling, venting and draining the system, or for opening the valve in
case of power failure. The valve can be restored manually to the
closed position by depressing the white manual lever lightly and
then pulling the lever out. The valve and actuator will return to the
automatic position when power is restored.
NOTE: If the valve is powered open, it cannot be manually
closed, unless actuator is removed.

WIRING

See figures 6a and 6b for single unit wiring details.
Multiple valves may be connected in parallel to a single controller
and transformer, up to the current rating of the controller and
transformer.
Fig. 6a - Connector Pin Configuration for Molex' Model
and 0 / 2 – 10 Vdc Controllers (Series 70).
L1
(HOT)
0 -
10 Vdc
L2
Fig. 6b - Wiring Colour Code for Cable Models and
0 / 2 – 10 Vdc Controllers (Series 70).
Brown
L1
(HOT)
+
0 -
10 Vdc
L2
CONDUIT CONNECTION
VC7934 may be installed as a plenum-rated cable model. Where
local codes require conduit , the conduit adapter may be used with
empty 3/8" flexible conduit to provide mechanical protection for the
wiring. All wiring connections must be made in an approved
electrical junction box. Refer to figure 7.
TM
connector.
+
6 5 4
3 2
1
� �
Black
Blue
Fig.7 - VC valve actuator electrical conduit installation

OPERATION

WITH SERIES 70, 0 / 2 - 10 VDC CONTROLLER
(refer to figure 8)
In the VC7900, an electronic circuit compares the voltage of the
feedback potentiometer to the signal voltage. If they are different,
then the circuit closes the appropriate triac and drives the motor in
the direction that will bring the circuit back into balance. In
addition, the standard limit switches maintain the travel to the
normal operating range.
Fig. 8 - Wiring Schematic of the VC7900 Series Actuators
Brown
24 Vac
Black
0 -10 Vdc
Blue
5
3
2
1
4
3
LS1
6
Feedback
Pot
2
95C-10830-2
LS2
Motor

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