21
Step 9 — Wire Field Controls
All field wiring must comply with local and national fire,
safety and electrical codes. Power to the unit must be within the
operating voltage range indicated on the unit’s nameplate.
Properly sized fuses or HACR circuit breakers must be in-
stalled for branch circuit protection. See unit nameplate for
maximum fuse or breaker size. The unit is provided with a con-
centric knock-out for attaching common trade sizes of conduit,
route power supply wiring through this opening. Always con-
nect the ground lead to the grounding lug provided in the con-
trol box and power leads to the line side of compressor contac-
tor as indicated on the wiring diagram.
CONSTANT TORQUE MOTORS (ECM) — For installa-
tions where the efficiency of an electronically commutated
brushless DC motor (ECM) motor is required, but the features
of a constant airflow motor are not required and comes stan-
dard with the constant torque ECM motor option. These mo-
tors feature up to 90% thermal efficiency combined with a flat-
ter fan curve than a PSC motor and simple operation.
These motors are provided with 5 speed taps to allow for a
wide range of airflow and external static options. To change a
speed tap follow the instructions below:
1. Disconnect power to the heat pump.
2. Remove the blower access panel.
3. Remove the speed tap wire from the terminal it is current-
ly connected to and connect it to the terminal desired.
Refer to Tables 7 and 8 for constant torque motor perfor-
mance tables for heat pump blower performance with the con-
stant torque motor option.
SAFETY DEVICES AND COMPLETE C CONTROL —
Each unit is factory provided with a Complete C board control-
ler that controls the compressor operation and monitors the
safety.
If the unit is being connected to a thermostat with a mal-
function light, this connection is made at the unit malfunction
output or relay. See to Fig. 18.
Safety controls include the following:
• High-pressure switch located in the refrigerant discharge
line and wired across the HPC terminals on the Complete
C Board.
• Low-pressure switch located in the unit refrigerant suc-
tion line and wired across terminals LPC1 and LPC2 on
the Complete C Board.
• Complete C Board Dry Contacts are Normally Open
(NO).
• Water side freeze protection sensor, mounted close to
condensing water coil, monitors refrigerant temperature
between condensing water coil and thermal expansion
valve. See Fig. 19. If temperature drops below or
remains at freeze limit trip for 30 seconds, the controller
will shut down the compressor and enter into a soft lock-
out condition. The default freeze limit trip is 30 F, how-
ever this can be changed to 15 F by cutting the R30 or
Freeze1 resistor located on top of DIP switch SW1.
Refer to Fig. 18 item 3 for resistor location.
• Evaporator freeze protection sensor, mounted between
the thermal expansion device and the evaporator, moni-
tors refrigerant temperature between the evaporator coil
and thermal expansion valve. See Fig. 20. If temperature
drops below or remains at freeze limit trip for 30 sec-
onds, the controller will shut down the compressor and
enter into a soft lockout condition. The default freeze
limit trip is 30 F.
• The condensate overflow protection sensor is located in
the drain pan of the unit and connected to the ‘COND’
terminal on the Complete C board.
WARNING
To avoid possible injury or death due to electrical shock,
open the power supply disconnect switch and secure it in
an open position during installation.
CAUTION
Operating the unit with improper line voltage or with
excessive phase imbalance is hazardous to the unit and
constitutes abuse and is not covered under warranty.
IMPORTANT: If the thermostat is provided with a mal-
function light powered off of the common (C) side of the
transformer, a jumper between R and COM terminal of
ALR contacts must be made.
IMPORTANT: If the thermostat is provided with a mal-
function light powered off of the hot (R) side of the trans-
former, then the thermostat malfunction light connection
should be connected directly to the (ALR) contact on the
unit’s Complete C board.
1
2
3
4
5
6
7
9
10
11
12
13
17
14
15
16
8
Fig. 18 — Complete C Control Board
1
—
Board Power Indicator
2
—
Control C Status LED Indicator
3
—
Water Coil Freeze Protection Tem-
perature Selection [R30]
4
—
Air Coil Freeze Protection Tempera-
ture Selection
5
—
Control C Board Settings
6
—
Water Coil Freeze Connection
7
—
Air Coil Freeze Connection
8
—
LED Status-Diagnostic Connection
9
—
24VAC Power Input
10
—
Compressor Contact Output
11
—
High Pressure Switch Connection
12
—
Call for Compressor Y1
13
—
Low Pressure Switch Connection
14
—
24VAC Power Common
15
—
Condensate Overflow Sensor
16
—
Dry Contact
17
—
Control C Ground Standoff