Johnson Controls YORK Tempo YLAA Series, Installation Operation & Maintenance

Page: 120 / 192

JOHNSON CONTROLS
120
FORM 150.72-NM1 (1020)
Commissioning
PREPARATION – POWER ON
Perform the commissioning using the
detailed checks outlined in the EQUIP -
MENT START­UP CHECK SHEET
as the commissioning procedure is
carried out.
Apply power to the chiller. Turn ON the option panel
circuit breaker if supplied.
The machine is now live!
Switch Settings
Assure the chiller OFF/ON UNIT switch at the bottom
of the keypad is OFF. Place the optional circuit breaker
handle on the panel door to ON. The customer’s
disconnection devices can now be set to ON.
Verify the control panel display is illuminated. Assure
the system switches under the SYSTEM SWITCHES
key are in the OFF position.
Compressor Heaters
Verify the compressor heaters are energized. If the
ambient temperature is above 96 °F (36 °C) the
compressor heaters must be on for at least 8 hours before
start-up to ensure all refrigerant liquid is driven out of
the compressor and the oil. If the ambient temperature
is below 86 °F (30 °C), allow 24 hours.
Water System
Verify the chilled liquid system has been installed
correctly, and has been commissioned with the correct
direction of water flow through the cooler. The inlet
should be at the refrigerant piping connection end of
the cooler. Purge air from the top of the cooler using
the plugged air vent mounted on the top of the cooler
body.
Flow rates and pressure drops must be within the limits
given in the Technical Data Section. Operation outside
of these limits is undesirable and could cause damage.
If mains power must be switched OFF for extended
maintenance or an extended shutdown period, the
compressor suction, discharge and economizer service
stop valves should be closed (clockwise). If there is
a possibility of liquid freezing due to low ambient
temperatures, the coolers should be drained or power
should be applied to the chiller. This will allow the
cooler heater to protect the cooler from freezing down to
–20 °F. Before placing the unit back in service, valves
should be opened and power must be switched on (if
power is removed for more than 8 hours) for at least 8
hours (24 hours if ambient temperature is below 86 °F
[30 °C]) before the unit is restarted.
Flow Switch
Verify a chilled water flow switch is correctly fitted in
the customer’s piping on the cooler outlet, and wired into
the control panel correctly using shielded cable.
There should be a straight run of at least 5 pipe diameters
on either side of the flow switch. The flow switch should
be connected to terminals 13 and 14 of XTBC1 on the
panel.
Temperature Sensor(s)
Ensure the leaving liquid temperature sensor is coated
with heat conductive compound (Part No. 013-00890-
000) and is inserted to the bottom of the water outlet
sensor well in the cooler. This sensor also provides some
freeze protection and must always be fully inserted in
the water outlet sensor well.