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EXTENDED UNIT SHUT-DOWN/
WINTERIZATION
If the system is taken out of operation for
long periods of time for any reasons (e.g.,
seasonal shutdown), use this procedure to
prepare the system for shutdown.
1. Check the refrigerant piping for leaks,
fixing any that exist.
2. Service the chilled water pump and any
air handling equipment according to the
manufacturer s recommendtions.
3. Open both electrical disconnect switches
for the unit and chilled water pump; lock
both disconnects in the open position.
WINTERIZATION: Close all evaporator
water supply valves and drain the
evaporator by removing the drain plug
and opening the vent on the entering
water line just outside the unit. Re-install
the drain plug. Since the evaporator does
not drain completely, add ethylene glycol
antifreeze to the remaining water through
the vent or evaporator drain hole, to keep
the water from freezing. Protect system
to 5.5 ° C below the expected ambient
temperature.
SYSTEM RESTART AFTER EXTENDED
SHUTDOWN
1. Remove winterization antifreeze as it can
reduce system capacity.
2. Fill the chilled water circuit by opening the
gate valves at the returning and supply
water piping. Be sure to vent the system
while filling it, and close the vents when
system is full.
3. Remove compressor delay on timer(s)
(TR1, TR2). Record down the original
socket for the respective timer so that the
correct timer(s) are replaced correctly
later.
4. Close the unit disconnect switch for power
supply.
5. Turn the REMOTE/OFF/ON switch to ON
position. With water circulating through
the chilled water system, inspect all
piping connections for leaks and make
any necessary repairs.
6. Adjust the water flow rate, using the
balancing valve, through the chilled water
circuit, and check the water pressure rise
(or drop) through the unit.
7. Adjust the flow switch (installed on the
unit outlet piping) to provide proper
operation.
NOTE: With the unit operating, throttle
the water flow to approximately 50% of
the full flow rate. Following the
manufacturer's instructions, adjust the
flow switch contacts to open at this
point. Use an ohmmeter to check for
contact opening and closure.
8. Stop the unit by turning the REMOTE/
OFF/ON switch to OFF position.
9. Replace compressor delay on timer (TR1,
TR2) back to their original sockets.
This unit now is ready for normal operation.
STANDARD AMBIENT
OPERATION
Standard unit will operate in outdoor ambient
temperature down to 15°C.
OPTIONAL LOW AMBIENT
OPERATION (CGAK)
A factory installed Low Ambient Unit (LAU)
option will enable units to operate at outdoor
ambient temperature down to 4°C (except
Model 100).
23
When the unit is started at ambient
temperature below 15.6°C, the low ambient
mode is activated. Timer TR3 & TR4 will
activate the solenoid valve connected
across the thermostatic expansion valves for
a period of 1.5 minutes, bypassing
refrigerant, to prevent suction pressure
dipping too low. Also, a fan cycle switch
prevents the condenser fan from starting
until the condensing pressure reaches 350
psig. This switch switches off condensing
fan when condensing pressure drops to 115
psig.
OPTIONAL HEAT PUMP
OPERATION (CGAR)
A factory installed heat pump unit (CGAR)
option will enable units to get either cooling
and heating performance (not simultaneous).
When the unit is switched to heating mode,
the four-valve is activated. Evaporator
becomes the condenser while the condenser
becomes the evaporator. There are two
liquid lines in a CGAR unit. One is for cooling
mode while another is for heating mode.
To carefully measure the high pressure,
there are two access ports in these two
liquid lines. If you operate this unit in cooling
mode, connect high pressure gauge to the
access port of the cooling liquid line. While
operating this unit in heating mode, must
change the connection to the access port of
the heating liquid line.
A timer override low pressure switch delays
for 2 minutes to prevent nuisance trip-outs.
CGA-SVX01A-EN
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