22 UNT Controller—Unitary Controller (UNT)
You may have either no earth ground connection, or one earth
ground connection which must be at the transformer secondary
common, whether one or multiple controllers are powered by the
same transformer.
COMMON
COMMON
TRACS
24VAC
24VAC
N2+
REF
N2-
ZBUS
COM
24VAC
+15VDC
+15VDC
L1
L2
T o
Load
isoxfmr2
Power
Transformer
120/24
Contactor
24 VAC
COM
ZBUS
REF
N2-
N2+
OK
Triac Jumper to
24 VAC only
Note: UNT110 is shown in illustration.
Diagram is for all UNT models.
NO!
Triac
BO1
BO2
BO3
70
COMMON
COMMON
COMMON
24 V
Figure 7: Transformer Wiring Diagram for UNT110/111,
UNT120/121, and UNT140/141 Series Controllers
You may connect the UNT power transformer secondary directly to earth
ground. If you elect to do so, the grounded side must connect to the
common power input terminal of the controller.
!
CAUTION: You may have a maximum of one single earth ground
connection, which must be at the transformer
secondary common, whether one or multiple
controllers are powered by the same transformer.
When grounding one side of the transformer
secondary, the grounded side must connect to the
common power input terminal.
Connecting the grounded side of the transformer to
the 24 VAC power input terminal will damage a
CBLPRO-1(-0) or laptop.
Grounding and
Isolation
UNT110/111,
120/121,
140/141
Summary of Contents for UNT Series
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