WARNING:
The cabinet must have an uninterrupted or
unbroken ground according to NEC, ANSI/NFPA 70-
1993, or local codes to minimize personal injury if an
electrical fault should occur. This may consist of electri-
cal wire or conduit approved for electrical ground when
installed in accordance with existing electrical codes. A
failure to follow this warning could result in an electrical
shock, fire, or death.
B.
Connect Ground and Power Wires
Connect ground wire to ground connection in control box for
safety. Connect power wiring to contactor. (See Fig. 5.)
C.
Connect Control Wiring
Route 24-v control wires through control wiring grommet and
connect leads to control wiring. (See Fig. 6.)
Use No. 18 AWG color-coded, insulated (35° C minimum) wires.
If thermostat is located more than 100 ft from unit (as measured
along the control voltage wires), use No. 16 AWG color-coded
wires to avoid excessive voltage drop.
Use furnace transformer, fan coil transformer, or accessory trans-
former for control power, 24-v/40va minimum.
NOTE:
Use of available 24-v accessories may exceed the mini-
mum 40-va power requirement. Determine total transformer load-
ing and increase the transformer capacity or split the load with an
accessory transformer as required.
NOTE:
The defrost timer is factory set for 90-minute cycles. The
timer can be field set for 30- and 50-minute cycles depending on
defrost conditions in your geographical location.
VII.
INSTALL ELECTRICAL ACCESSORIES
Refer to the individual instructions packaged with the kits or
accessories when installing.
VIII.
START-UP
1. If equipped with a crankcase heater, energize heater a
minimum of 24 hrs before starting unit. To energize heater
only, set thermostat at OFF position and close electrical
disconnect to outdoor unit.
2. Fully open liquid and vapor tube service valves.
3. Unit is shipped with valve stem(s) front seated, and caps
installed. Replace stem caps after system is opened to
refrigerant flow. Replace caps finger-tight and tighten
additional 1/6 turn using a backup wrench on valve body
flats to prevent distortion of sheet metal.
4. Close electrical disconnects to energize system.
5. Set room thermostat at desired temperature.
6. Set room thermostat at HEAT or COOL and fan switch at
ON or AUTO, as desired. Operate unit for 15 minutes.
Check
system
refrigerant
charge.
(See
Section
IX—Checking Charge.)
WARNING:
Relieve pressure and recover all refrigerant
before system repair or final unit disposal to avoid
personal injury or death. Use all service ports and open all
flow-control devices, including solenoid valves.
A.
Sequence of Operation
NOTE:
Defrost control board is equipped with 5-minute lockout
timer which may be initiated upon any interruption of power.
NOTE:
With power supplied to indoor and outdoor units, trans-
former is energized.
COOLING
On a call for cooling, the thermostat makes circuits R-O, R-Y, and
R-G. Circuit R-O energizes reversing valve, switching it to cooling
position. Circuit R-Y energizes contactor, starting outdoor fan
motor and compressor. R-G energizes indoor unit blower relay,
starting indoor blower motor on high speed.
When the thermostat is satisfied, its contacts open, de-energizing
contactor and blower relay. Compressor and motors should stop.
HEATING
On a call for heating, the thermostat makes circuits R-Y and R-G.
Circuit R-Y energizes contactor, starting outdoor fan motor and
compressor. Circuit R-G energizes indoor blower relay, starting
blower motor on high speed.
Should the temperature continue to fall, R-W2 is made through the
second-stage room thermostat bulb. Circuit R-W2 energizes a
sequencer, bringing on the first bank of supplemental electric heat
and providing electrical potential to the second heater sequencer (if
used). If outdoor temperature falls below the setting of the outdoor
thermostat (field-installed option), contacts close to complete the
circuit and bring on the second bank of supplemental electric heat.
When thermostat is satisfied, its contacts open, de-energizing
contactor and sequencer. All heaters and motors should stop.
DEFROST
The defrost control is a time/temperature control which includes a
field-selectable (quick-connects located at board edge) time period
between defrost cycles (30, 50, and 90 minutes), factory set at 90
minutes.
The electronic timer and the defrost cycle will start only when
contactor is energized and defrost thermostat is closed.
The defrost mode is identical to the cooling mode except the
outdoor fan motor stops and a second-stage heat is turned on to
continue warming the conditioned space.
IX.
CHECKING CHARGE
Factory charge is shown on unit rating plate.
WARNING:
Service valve gage ports are equipped with
Schrader valves. To prevent personal injury, wear safety
glasses and gloves when handling refrigerant.
CAUTION:
Compressor damage may occur if system is
overcharged.
Adjust charge in cooling mode by following procedure shown on
superheat/subcooling (TXV) label and check charge in heating
mode by following procedure shown on heating check chart, both
located on unit.
Fig. 5—Line Power Connections
A88174
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