Trane RTWB Helical-Rotary Installation Operation & Maintenance page 31

Start up procedure
General
If the pre-start checkout, as
discussed above, has been
completed, the unit is ready to start.
The Clear Language Display is
shown in Figure 12. Complete each
step in sequence, as follows:
[ ] Press the Stop key on the Clear
Language Display.
[ ] As necessary, adjust the setpoint
values in the Clear Language
Display menus.
[ ] Close the fused disconnect
switch for the chilled-water pump
and the condenser-water pump.
Energize the pumps to start the
water circulation.
[ ] Check the service valves on the
discharge line, suction line, oil
line, and liquid line for each
circuit. These valves must be
open before starting the
compressors.
C C A A U U T T I I O O N N
To prevent compressor damage, do
not operate the unit until all
refrigerant and oil-line service valves
are opened.
[ ] Verify that the chilled-water pump
runs for one minute after the
chiller is commanded to stop (for
normal chilled-water systems).
[ ] Press the Auto key. If the chiller
control calls for cooling and all
safety interlocks are closed, the
unit will start. The compressor(s)
will load and unload in response
to the temperature of the leaving
chilled-water temperature.
RTWB-SVN01B-E4
Unit Start-Up
Procedures
After the system has been operating
for approximately 30 minutes and
has become stabilized, complete the
start-up procedures as follows.
[ ] Check the evaporator refrigerant
pressure and the condenser
refrigerant pressure under the
Refrigerant Report on the Clear
Language display.
[ ] Measure the system superheat.
[ ] Measure the system subcooling.
[ ] A shortage of refrigerant is
indicated if the operating
pressures are low and the
subcooling is also low. If the
operating pressures, superheat,
and subcooling readings indicate
a refrigerant shortage, gas-charge
refrigerant into each circuit as
required. With the unit running,
add refrigerant vapor by
connecting the charging line to
the suction service valve and
charging through the backseat
port until operating conditions
become normal.
C C A A U U T T I I O O N N
If both suction and discharge
pressures are low and subcooling is
normal, a problem other than
refrigerant shortage exists. Do not
add refrigerant, as this may result in
overcharging the circuit.
Use only the refrigerant specified on
the unit nameplate, to prevent
compressor damage and insure full
system capacity.
[ ] If operating conditions indicate a
refrigerant overcharge, remove
refrigerant at the liquid line
service valve. Allow refrigerant to
escape slowly to minimize oil
loss. Do not discharge refrigerant
into the atmosphere.
W W A A R R N N I I N N G G
Do not allow refrigerant to directly
contact skin, or injury from frostbite
may result.
System superheat
Normal suction superheat for each
circuit is approximately 3°C at full
operating load. Superheat
temperature can be expected to be
moving around a 3°C setpoint when
the chiller is pulling down or when
the compressor slide valve is being
modulated.
System subcooling
Normal subcooling for each circuit
ranges from 5.5°C to 11°C,
depending on the unit. If subcooling
for either circuit does not
approximate these figures, check the
superheat for the circuit and adjust
it, if required. If superheat is normal
but subcooling is not, contact a
qualified service technician.
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