4
McQuay IM 846
Installation Instructions
5
On the circuit board, set the voltage selection switch
(Figure 2) to the appropriate voltage for the application
•
24 V = 24 VAC
•
110–277 V = 120, 240, or 277 VAC
.
Note:
The circuit board is shipped with the voltage selection switch
in the 110-227 V position. For 24 VAC use, the switch must
be in the 24 V position.
6
The circuit board is also equipped with configuration
jumpers (JP1, JP3, and JP4 in Figure 2). Depending on the
application, it may be necessary to reconfigure the
following jumpers:
• JP4:
2/4 Pipe Sensor Jumper - This jumper selects
between 2-pipe (jumper ON) and 4-pipe (jumper OFF)
operation (see “Fan Operation” on page 7).
• JP3:
Door/Window Switch Jumper - This jumper is
shipped normally open. Placement of a jumper allows
for occupancy detection and door/window switch only
operation (see “Optional Occupancy Detection
Equipment Operation” on page 9).
• JP1:
Removal of this jumper allows the sensor to be
located in a remote location.
7
Connect the color coded thermostat wires (Figure 3) to the
line voltage wires located in the mud ring/connection box
and secure the connections with wire nuts.
Figure 3: Wiring diagram
8
Install the thermostat base to the mud ring/outlet box using
two furnished mounting screws. Tighten the screws evenly
but do not over tighten.
Note:
An output ratings chart (Table 3) is located on the
inside of the base.
Table 3: Output ratings
9
With the base now secured, verify that the circuit board is
firmly snapped into the cover and is not dislodged.
10
Install the cover assembly to the base, pressing firmly to
engage the cover locking snaps.
CAUTION
Before applying power, the voltage selection switch must be in
the appropriate position. Failure to select the correct voltage
can cause thermostat malfunction or permanently damage the
thermostat.
CAUTION
To use a remote sensor on units with local sensing capability,
remove jumper JP1 to disable local sensing. Failure to remove
JP1 can cause improper operation of the thermostat with a
remote probe installed.
CAUTION
Use copper wire only. Insulate or wire nut all unused leads.
Avoid electrostatic discharge to the thermostat.
Failure to do so can cause thermostat malfunction or
permanently damage the thermostat.
Output ratings
Voltage
Inductive
Resistive
amps
Pilot duty
HP
FLA
LRA
24 VAC
NA
NA
NA
24 VA
NA
120 VAC
5.8
34.8
6.0
125 VA
1/4
240 VAC
2.9
17.4
5.0
125 VA
1/4
277 VAC
2.4
14.4
4.2
125 VA
1/4
DANGER
Hazardous voltage. Combined load current is not to exceed 20
amps. Mount only to a grounded metallic box.
Low voltage wiring is Class 2. To avoid electrical shock or
damage to equipment, disconnect power before installing or
servicing. Failure to follow these instructions will result in death
or serious injury.
THERMOST
AT
CONNECTIONS
LOW
V
OL
T
A
GE
LINE
V
OL
T
A
GE
White/Black
White/Yellow
White/Violet
White/Blue
White/Gray
White/Brown
White/Red
White/Orange
Yellow
Blue
Red
Black
Brown
Setback input/door switch
Remote probe
Circuit common
Pipe sensor
L2/Neutral
Occupacy detector
L1
Outputs
(see ratings)
Accessories
available
from
McQuay
Cool
(main output)
Heat
(secondary output)
Fan low
Fan medium
Fan high
Outside air
