10
513 01 3402 02
Control Voltage Connections
NOTE
: Do not use any type of power
−
stealing thermostat. Unit
control problems may result.
Use no. 18 American Wire Gage (AWG) color
−
coded, insulated
(35
°
C minimum) wires to make the control voltage connections
between the thermostat and the unit. If the thermostat is located
more than 100 ft (30.5 m) from the unit (as measured along the
control voltage wires), use no. 16 AWG color
−
coded, insulated
(35
°
C minimum) wires.
Standard Connections
Locate the low voltage terminal board in 24 volt splice box. See
FIGURE 10 for connection diagram. Run the low
−
voltage leads
from the thermostat, through the control wiring inlet hole
grommet (FIGURE 3 and FIGURE 4), and into the low
−
voltage
splice box. Provide a drip loop before running wires through
panel. Secure and strain relief all wires so that they do not
interfere with operation of unit.
If an accessory electric heater is installed, low voltage leads from
heater must be connected to low voltage terminal board W1 and
C terminals.
Transformer Protection
The transformer is protected by a 24 volt circuit breaker. If an
overload or short is present, correct overload condition and reset
24 volt circuit breaker.
Special Procedures for 420
−
v Operations
ELECTRICAL SHOCK HAZARD
Failure to follow this warning could result in personal
injury or death.
Before installing or servicing system, always turn off
main power to system and install lockout tag.
!
WARNING
The transformer in the unit has two taps, 380 and 415 volts. For
power supplies above 400 volts, the transformer must be
connected to the 415 volt tap. With power off, disconnect blue
wire from transformer splice connection and connect black wire
from transformer to splice connection. Insulate unused blue
transformer tap. See transformer label. During unit start
−
up,
check secondary voltage to ensure that a minimum of 20 volts is
available during unit operation, and that voltage does not exceed
29 volts while unit is off.
Accessory Electric Heaters Installation
Electric heaters may be installed with the PH4E units per
instructions supplied with electric heater package. See unit rating
plate for factory
−
approved electric heater kits.
Sequence of Operation
a. CONTINUOUS FAN
(1.) Thermostat closes circuit R to G energizing the
blower motor for continuous fan.
b. COOLING MODE
(1.) If indoor temperature is above temperature set
point, thermostat closes circuits R to G, R to Y1
and R to O (Y2). The compressor, indoor and
outdoor fans, and reversing valve are energized.
c. ELECTRIC HEATING MODE
(1.) Thermostat closes circuit R to W/W1, or W2 and R
to G. There are no on or off delays.
d. HEAT PUMP HEATING MODE
(1.) Thermostat closes circuits R to G and R to Y1.
The compressor, indoor and outdoor fans are
energized.
e. HEAT PUMP HEATING WITH AUXILIARY ELECTRIC
HEAT
(1.) Thermostat closes circuits R to G, R to Y1 and R
to W/W1 or W2. The compressor, indoor and
outdoor fans are energized, as well as the electric
heat relays.
f. DEFROST MODE
The defrost mode is automatically energized by the
defrost board during heating mode. The defrost board
energizes “O” (reversing valve) and “W2” (electric
heat). It also de
−
energizes the outdoor fan. When
defrost is complete, unit will return to heating mode. If
room thermostat is satisfied during defrost, unit will
shut down and restart in defrost on next call for heat.
FIGURE 11
Typical Installation
INDOOR
THERMOSTAT
DISCONNECT
PER NEC
FROM
POWER
SOURCE
RETURN
AIR
TOP COVER
POWER ENTRY
CONTROL ENTRY