12
• If the pressure measured in step 1 is less than the
required liquid refrigerant pressure determined in
step 3, then there is too little charge in the system.
Add refrigerant and repeat steps 1 through 3 until
the system is correctly charged.
Charging the Unit in Heating Mode
1. Evacuate the refrigerant system.
2. Weigh in the proper charge as indicated on the unit
label. Unit charge MUST be verified in cooling season.
3. Verify the unit is operating properly according to the
System Heating section on
.
Forced Defrost Mode (Field Test)
•
When the
TEST
terminals are shorted with the
Y
input
active and pressure switches closed, the ACST will
be eliminated and the compressor contactor output
energizes within 2 seconds. When the
TEST
terminals
are shorted for more than 9 seconds with the Y input
active, the control will be placed into a forced defrost
mode.
NOTE:
The coil temperature sensor does not need to
be cold when the unit is forced into defrost.
• After the
TEST
input is shorted, the defrost mode
will terminate in 13.7 minutes or less or when the coil
temperature is above the terminate set point or when
the thermostat
Y
input is removed, whichever occurs
first.
Anti Short Cycle Timer Test
The 5 minute time delay feature can be bypassed by
shorting the
TEST
pins together.
Heating Mode
When the
TEST
pins are shorted together for more than
1 second, the control will switch between defrost mode
and heating mode as described in the Forced Defrost
Mode procedure section.
Cooling Mode
When the
TEST
pins are shorted together for more than
1 second, the Anti Short Cycle Timer will be bypassed.
COMPONENT FUNCTIONS
Low Pressure Switch
The low pressure switch is factory installed and located in
the suction line internal to the unit. The switch is designed
to protect the compressor if a loss of charge occurs. Under
normal conditions, the switch is closed.
If the suction pressure falls below 5 psig, then the switch will
open and de-energize the unit. The switch will close again
once the suction pressure increases above 20 psig. The low
pressure switch interrupts the thermostat inputs to the unit.
NOTE:
When the switch opens and then closes, there
will be a 5 minute short cycling delay before the unit can
energize.
High Pressure Switch
The high pressure switch is factory installed and located
in the compressor discharge line internal to the unit. The
UNIT MAINTENANCE
WARNING:
To prevent electrical shock, personal injury, or
death, disconnect all electrical power to the unit
before performing any maintenance or service.
The unit may have more than one electrical supply.
Proper maintenance is important to achieve optimum
performance from the heat pump. The ability to properly
perform maintenance on this equipment requires certain
mechanical skills and tools. If you do not possess these
skills, contact your dealer for maintenance. Consult your
local dealer about the availability of maintenance contracts.
Routine maintenance should include the following:
• Inspect and clean or replace air filters at the beginning
of each heating and cooling season, or more frequently
if required.
• Inspect the condensate drain and outdoor coil at the
beginning of each cooling season. Remove any debris.
Clean the outdoor coil and louvers as necessary using a
mild detergent and water. Rinse thoroughly with water.
• Inspect the electrical connections for tightness at the
beginning of each heating and cooling season. Service
as necessary.
CAUTION:
The unit should never be operated without a
filter in the return air system. Replace disposable
filters with the same type and size.
• Do not attempt to add additional oil to motors unequipped
with oil tubes. The compressor is hermetically sealed
at the factory and does not require lubrication.
switch is designed to de-energize the system when very
high pressures occur during abnormal conditions. Under
normal conditions, the switch is closed.
If the discharge pressure rises above 650 psig, the switch
will open and de-energize the unit. The switch will close
again once the discharge pressure decreases to 460
psig. The high pressure switch interrupts the thermostat
inputs to the unit.
NOTE:
When the switch opens and
then closes, there will be a 5 minute short cycling delay
before the unit can energize.
