Operation; Start-Up Procedure - Trane CGA-SVX01A-EN Installation, Operation And Maintenance Manual

START-UP PROCEDURE

Close the fused disconnect switch and
turn REMOTE/OFF/ON switch to ON.
Pump will start immediately. After 2
minutes, compressors 1 will start. 1
minute later, compressor 2 will start
(only in units with two refrigerant circuits).
For CGAR models, turn REMOTE/OFF/
ON switch to ON as described above,
turn the already installed indoors cooling
and heating mode switch to cooling
mode, then the operation of the chiller
would be similar to what is described
above (see section on electrical wiring of
the installation checklist). As for start-up
with heating mode, first turn REMOTE/
OFF/ON switch to OFF. Then, turn the
cooling and heating mode switch to
heating. Finally, turn the REMOTE/OFF/
ON switch to ON.
To start-up the CGAR at the chiller i.e.
outdoors, remove the wiring of indoors
cooling and heating mode switch. For
CGAR-030 to CGAR-075, connect wiring
across terminals 12 & 13 for cooling
mode, terminals 12 & 17 for heating
mode. For CGAR-100, CGAR-125, and
CGAR-150, connect wiring across
terminals 17 & 18 for cooling mode and
terminals 17 & 27 for heating mode. After
the completion of testing, reconnect the
wiring of indoors cooling and heating
mode switch back to the original
terminals.
Once the unit has operated for at least 30
minutes and the system has stabilized,
complete the following checklist to ensure
proper unit operation.
Re-check unit water flow and pressure
rise (for no built-in pump unit with field-
installed pump system). These readings
should be stable at proper levels.
© American Standard Inc. 2001

OPERATION

Measure unit suction and discharge
pressures by installing pressure gauges
on the discharge and suction line access
ports. Normal operation should render
suction pressure in the range of 50-85
psig and discharge pressure 200-310
psig.
Check compressor amp draw.
Check electrical power supply.
Check the liquid line sight glasses.
NOTE: Bubbles in the liquid line may
indicate either a low refrigerant charge,
or excessive pressure drop in the liquid
line. Such a restriction can often be
identified by a noticeable difference in
line temperature on either side of the
restricted area. (Frost often forms on the
outside of the liquid line at the point of
restriction, as well). Bubbles are not
necessarily a symptom of improper
system operation.
CAUTION: A clear sight glass does not
necessarily mean that the system is
sufficiently charged; be sure to consider
system superheat, subcooling, and unit
operating pressures and ambient
temperatures.
Proper unit refrigerant charge-per circuit-is
indicated on the unit nameplate.
Measure system superheat.
Normal system superheat is 6.7°C to 8.3°C
for each circuit at ARI conditions (12.2°C
entering water, 6.7°C leaving water, and
35°C ambient temperature). If the superheat
measured for either circuit does not fall
within this range, alter the setting of the
superheat adjustment on the thermal
expansion valve to obtain the desired
reading. Allow 15 to 30 minutes between
adjustments for the expansion valve to
stabilize at each new setting.
22
Measure system subcooling.
Normal subcooling for each circuit is 6.7°C
to 12.2°C ARI conditions (12.2°C entering
water, 6.7°C leaving water, and 35°C
ambient temperature). If subcooling for
either circuit is normal but subcooling is not
in this range, check superheat for the circuit
and adjust, if required. If superheat is normal
but subcooling is not, contact a qualified
service technician.
If operating pressure, sight
glass,superheat and subcooling readings
indicate refrigerant shortage, find and
repair leaks and, gas-charge refrigerant
into each circuit. Refrigerant shortage is
indicated if operating pressures are low
and subcooling is also low.
CAUTION: If suction and discharge
pressures are low, but subcooling is
normal, no refrigerant shortage exists.
Adding refrigerant will result in
overcharging.
Add refrigerant vapor with the unit running
by charging through the access port on the
suction line until operating pressures are
normal.
If operating pressures indicate an
overcharge, slowly (to minimize oil loss)
recover refrigerant at the liquid line
service valve.
Be sure that all remote sensing bulbs are
properly installed in bulb wells with heat
transfer grease. Remote bulb capillary
tubes must be secured (i.e. protected
from vibration and abrasion) and
undamaged.
Inspect the unit. Remove any debris,
tools and hardware. Secure all exterior
panels, including the control and
compressor access panels. Replace and
tighten all retaining screws.
CGA-SVX01A-EN