Thermo Pride Air Handler Modular MV - Manual (Page 6)

6
CONVENTIONAL LOW VOLTAGE CONTROL WIRING
(24 VAC)
The 24 volt power supply is provided by an internally wired low voltage
transformer which is standard on all models, However, if the unit is con-
nected to a 208 volt power supply, the low voltage transformer must be
rewired to the 208 volt tap. See the unit wiring label.
Field supplied low voltage wiring can exit the unit on the top right hand
corner or the right hand side panel. Refer to Figure 3.
Remove desired knockout and pierce foil faced insulation to allow wir-
ing to pass through. Use as small of a hole as possible to minimize air
leakage.
Install a 7/8” plastic bushing in the selected hole and keep low voltage
wiring as short as possible inside the control box.
To further minimize air leakage, seal the wiring entry point at the outside
of the unit.
The field wiring is to be connected at the screw terminals of the control
board. Refer to Figure 6 or 7.
The low voltage connections may be connected to the screw terminals
or the quick connect terminals. The screw terminals and the quick con-
nect terminals are physically connected on the control board.
FIGURE 6: Air Handler Control Board – Communications Connections
SPARE JUMPER
HEAT ENABLE JUMPER HUMIDIFIER OUT PUT EAC OUTPUT
THERMOSTAT CONNECTIONS CONTINUOUS FAN JUMPER
BLOWER SPEED
JUMPERS
HUMIDSTAT
JUMPER
AC/HP JUMPER
All wiring must comply with local and national electrical code
requirements. Read and heed all unit caution labels.
It is possible to vary the amount of electric heat turned on during the
defrost cycle of a heat pump. Standard wiring will only bring on the
first stage of electric heat during defrost. See Heat Output and Limit
Connections and Table 4 for additional information on heat during
defrost cycle.
NOTICE
TABLE 2: Low Voltage Connections
Terminal Signal Comment
R 24 VAC power (fused)
G Continuous Fan operation
Y/Y2
Second or full stage
compressor operation
Y1
First stage compressor
operation
Not used with outdoor units
having one stage compressors.
W2 Second stage heat operation
W1 First stage heat operation
O Reversing valve operation
24 VAC will be present at this
terminal when the MODE
jumper is in the AC position.
This is normal.
HUM Humidity switch input
24 VAC will be present at this
terminal when the HUM STAT
jumper is in the NO position.
This is normal.
X/L
Connection point for
heat pump fault indicator
This terminal is a connection
point only and does not affect
air handler control operation.
COM 24 VAC common