14
Refrigeration System Checks
This unit is equipped with thermal expansion valves.
Ensure the hold-down bolts on the compressor are secure
and have not vibrated loose during shipment. Check
that the vibration grommets have been installed and
visually check all piping for damage and leaks and repair
if necessary. The entire system has been factory charged
and tested, making it unnecessary to field charge. Factory
refrigerant charge is shown on the unit’s nameplate.
To confirm charge levels or, if a leak occurs and charge
needs to be added to the system, it is recommended to
evacuate the system and recharge refrigerant to the unit’s
nameplate specifications. This unit has been rated in the
cooling mode at the AHRI rated conditions of: indoor (80°F
db/67°F wb) and outdoor (95°F db). While operating at this
condition, the superheat should range from 9°F to 11°F for
each refrigeration circuit measured at the suction service
port located near the compressor.
Start-Up Procedure and Checklist
Begin with power turned off at all disconnects.
Air Conditioning Start-Up Procedure
1. Ensure the thermostat is set to OFF and Fan is set
to Auto.
2.
Inspect all registers and set them to the normal open
position.
3. Turn on the electrical supply at the disconnect.
4. Turn the fan switch to the “ON” position. The blower
should operate after a 7 second delay.
5. Turn the fan switch to “Auto” position. The blower
should stop after a 60 second delay.
6. Set the thermostat to Cool mode and slowly
lower the cooling temperature until the unit starts.
The compressor, blower and fan should now be
operating. Allow the unit to run 10 minutes, make
sure cool air is being supplied by the unit.
7. Check that the compressor is operating correctly.
The scroll compressors in these units MUST operate
in the proper rotation. To ensure the compressors
are operating in the correct direction, check the
compressor discharge line pressure or temperature
after the compressor is started. The discharge
pressure and discharge line temperature should
increase. If this does not occur and the compressor
is producing an exceptional amount of noise,this
indicates that there is a phasing issue.
Perform the following to correct:
7.1 Turn power to the unit OFF.
7.2 Switch any two leads of power supply at unit
Single Point Power Block.
7.3 Turn power to the unit ON.
7.4 Perform step 7 again.
8. Turn the temperature setting to the highest position,
stopping the unit. The indoor blower will continue to
run for 60 seconds.
9. Turn the thermostat system switch to “OFF” and
disconnect all power when servicing the unit.
NOTE: The compressor has 180 second re-start
delay on timer to avoid short cycling.
WARNING
HIGH VOLTAGE!
Disconnect all power before
servicing or installing this unit.
Multiple power sources may be
present. Failure to do so may cause
property damage, personal injury or
death.
Heat Pump Start-Up Procedure
10.
Check the cooling mode for the heat pump in
the same manner as above. The reversing valve
is energized when the thermostat is placed in
the cooling position. A clicking sound should be
noticeable from the reversing valve. By lowering the
temperature setting to call for cooling, the solenoid
valve is energized. The compressor, blower and fan
should then be running. After the cooling mode is
checked out, turn the thermostat system switch to
“OFF”.
11. Turn the thermostat system switch to “HEAT” and fan
switch to “AUTO”.
12. Slowly raise the heating temperature setting. When
the heating first stage makes contact, stop raising
the temperature setting.. The compressor, blower
and fan should now be running with the reversing
valve in the deenergized (heating) position. After
giving the unit time to settle out, make sure the unit
is supplying heated air.
Note: If the outdoor ambient is above 80°F, the
unit may trip on its high pressure cut out when on
heating. The compressor should stop. The heating
cycle must be thoroughly checked, so postpone
the test to another day when conditions are more
suitable but-DO NOT FAIL TO TEST. If the outdoor
ambient is low and the unit operates properly on the
heating cycle, you may check the pressure cutout
operation by blocking off the indoor return air until
the unit trips.
13. Once the heating has been confirmed, raise the
temperature setting until the second stage heating
makes contact. Supplemental resistance heat, if
installed should now come on. Make sure it operates
properly.
14. For thermostats with emergency heat switch, set
thermostat to Emergency Heat mode. The heat
pump will stop, the blower will continue to run, all
heaters will come on and the thermostat emergency
heat light will come on. Confirm heaters operate
normally.
