Honeywell CVL4022ASVAV1 Engineering Manual page 13

to Class II restrictions (U.S. only), the transformer must not be
larger than 100 VA. Fig. 10 depicts a single controller using
one transformer.
IMPORTANT:
Power must be off prior to connecting to or removing
connections from the 24 Vac power (24 Vac/24 Vac COM),
earth ground (EGND), and 20 Vdc power (20 Vdc) terminals.
IMPORTANT:
Use the heaviest gauge wire available, up to 14 AWG (2.0 sq
mm), with a minimum of 18 AWG
(1.0 sq mm), for all power and earth ground wiring. Screw-
type terminal blocks are designed to accept up to one 14
AWG (2.0 sq mm) conductor or up to two 18 AWG (1.0 sq
mm) conductors. More than two wires that are 18 AWG (2.0
sq mm) can be connected with a wire nut. Include a pigtail
with this wire group and attach the pigtail to the terminal block.
IMPORTANT:
If the controller is used on Heating and Cooling Equipment
(UL 1995, U.S. only) and the transformer primary power is
more than 150 volts, connect terminal 2, (the 24 Vac common
[24 VAC COM] terminal) to earth ground (see Fig. 11). For
these applications, only one controller can be powered by
each transformer.
NOTES:
—Unswitched 24 Vac power wiring can be run in the same
conduit as the LONWORKS® cable.
—Maintain at least a 3 in. (7.6 cm) separation between Triac
outputs and LONWORKS® wiring throughout the installation.
CONNECT POWER TO
TERMINALS 1 AND 2
COM
24 VAC
TRANSFORMER
Fig. 10. Power wiring details for one controller.
ΔP
1 1 1 1 1 1 1 2 2 2 2 2
3 4 5 6 7 8 9 0 1 2 3 4
1 1
1 2 3 4 5 6 7 8 9 0 1 2
EARTH
GROUND
(TERMINAL 3)
OUTPUT
DEVICE
POWER
M33634
CONNECT POWER TO
TERMINALS 1 AND 2
TRANSFORMER
LINE VOLTAGE
1
GREATER
THAN 150 VAC EARTH
GROUND
1 IF THE CONTROLLER IS USED IN UL 1995 EQUIPMENT AND THE
PRIMARY POWER IS MORE THAN 150 VOLTS, GROUND 24 VAC COM
SIDE OF TRANSFORMER SECONDARY.
Fig. 11. Transformer power wiring details for one
controller used in UL 1995 equipment (U.S. only).
More than one controller can be powered by a single
transformer. Fig. 15 shows power wiring details for multiple
controllers.
NOTE: Controller configurations are not necessarily limited to
three devices, but the total power draw, including accessories,
cannot exceed 100 VA when powered by the same
transformer (U.S. only). For power wiring recommendations,
see "Wiring" on page 12.
Power
Before wiring the controller, determine the input and output
device requirements for each controller used in the system.
Select input and output devices compatible with the controller
and the application. Consider the operating range, wiring
requirements, and the environment conditions when selecting
input/output devices. When selecting actuators for modulating
applications, consider using floating control. In direct digital
control applications, floating actuators will generally provide
control action equal to or better than an analog input actuator
for lower cost.
Determine the location of controllers, sensors, actuators and
other input/output devices and create wiring diagrams. Refer
to Fig. 19-Fig. 20 beginning on page 20 for illustrations of
typical controller wiring for various configurations.
The application engineer must review the control job
requirements. This includes the sequences of operation for
the controller, and for the system as a whole. Usually, there
are variables that must be passed between the controllers that
are required for optimum system wide operation. Typical
examples are the TOD, Occ/Unocc signal, the outdoor air
temperature, the demand limit control signal, and the smoke
control mode signal.
It is important to understand these interrelationships early in
the job engineering process, to ensure proper implementation
when configuring the controllers.
13
ΔP
1 1 1 1 1 1 1 2 2 2 2 2
3 4 5 6 7 8 9 0 1 2 3 4
1 1
1 2 3 4 5 6 7 8 9 0 1 2
EARTH
COM
GROUND
(TERMINAL 3)
24 VAC
OUTPUT
DEVICE
POWER
M33635
31-00083—02