Filter
Top Products
Chapter 4 Input/output functions and wiring for typical applications
22 CNT-SVX07C-EN
Overriding binary outputs
The Tracer ZN521 controller includes a manual output test and a water
valve override feature. Use the manual output test to manually control
the outputs in a defined sequence. For information, see “Manual output
test” on page 52.
The water valve override feature is a procedure used for water balancing.
Using the Rover service tool or a BAS, a user can specify that a Tracer
ZN521 override the state of water valves to:
• Open all valves
• Close all valves
The controller resets itself to normal operation after two hours.
Wiring requirements and options
Table 7 shows required controller inputs for minimal proper operation of
all applications.
Figure 7 on page 23 through Figure 17 on page 33 show typical applica-
tions that include all required and all optional components.
Table 7. Required controller inputs for proper operation
Function Input source
For more information,
see:
24 Vac power Terminals: GND, 24 V “AC-power wiring” on
page 7
Zone temperature Terminals: ZN, GND
or communicated
“ZN: Zone tempera-
ture” on page 16
Discharge air temperature Terminals: AI2 “AI2: Discharge air tem-
perature” on page 18
Entering water tempera-
ture—required only for
units with auto
changeover
Terminal: AI1
or communicated
“AI1: Entering water
temperature” on
page 17
Outdoor air temperature—
required only for econo-
mizing
Terminals: AI3 or
communicated
“AI3: Outdoor air tem-
perature or generic
temperature” on
page 18
Relative humidity—
required only for dehu-
midification
Terminals: AI4 “AI4: Universal 4–
20 mA” on page 19