Optional Surface Mount Thermostat Connection Wiring; Optional Remote Mounted Thermostat Wiring; Figure 8 - Field Wiring Diagram; Figure 9 - Remote Thermostat Wiring - Johnson Controls VB09 Installation, Operation And Maintenance Manual

FORM 145.18-IOM1
ISSUE DATE: 8/30/2018
Install the thermostat by connecting the remote ther-
mostat wiring to microprocessor board low voltage
terminal strip. See Figure 8 for typical wiring connec-
tions.
Ensure that the control wiring between the thermostat
and the unit's terminations does not exceed 1 ohm.
Resistance in excess of 1 ohm may cause
component damage due to insufficient AC
voltage supply.
Check all loads and conductors for
grounds, shorts, or miswiring. Do not run
the low voltage wiring in the same conduit
with the high voltage power wiring.

TABLE 4 - TYPICAL WIRE CONNECTIONS

RECOMMENDED WIRE
SIZE (GAUGE)
20
18
16

FIGURE 8 - FIELD WIRING DIAGRAM

MAXIMUM LOW VOLTAGE
WIRE LENGTH (FEET)
50
75
125
LD19520
Optional Surface Mount Thermostat
Connection Wiring
For applications where the thermostat is mounted di-
rectly above the return air (RA) panel, select cabinet
control option P (for example, VB12P). The thermostat
Molex pigtail harness (shipped loose) is field wired to
thermostat terminals. The Molex connector clips to the
panel-mounted, mating Molex connector on unit cabi-
net that is located 7 inches above the electrical box. See
optional 24V surface mount connection in Figure 3 on
page 14.

Optional Remote Mounted Thermostat Wiring

For units ordered with an extended thermostat harness
option, the thermostat is remote mounted. A specific,
plenum rated extended harness length can be ordered.
Use low voltage 7/8-inch knock-out on the side of the
unit at the electrical box to field wire the low voltage
thermostat wiring. Using a plastic bushing to pass the
harness inside electrical box to the factory wired mat-
ing Molex harness (see Figure 9). The thermostat pig-
tail Molex harness ships loose for field wiring to the
thermostat terminals.
LD27629

FIGURE 9 - REMOTE THERMOSTAT WIRING

SECTION 1 - INSTALLATION
LD27630
19
1