Trane CGAD020 Installation Operation & Maintenance Download Page 17

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CGAD-SVN02C-EN

refrigerant into the atmosphere.

[ ] Fill out the "Start-up Sheet" that comes
with the equipment.

Once the unit is operating normally,
keep the machine house clean and the

tools in place. Make sure that the
doors of the control panels are in
place.

New regulationSuperheat of the

New regulation

The normal superheat for each circuit is
5°C to 10°C at full charge. If the superheat
is not within this range, adjust the

calibration of the superheat of the
expansion valve. Allow 5 to 10 minutes
between the adjustments to give time for

the expansion valve to stabilize after each
new adjustment.

Sub-cooling System
The normal sub-cooling each circuit is 6 °
C to 12 ° C at full load. If the sub-cooling

isn’t in this range, check the circuit
overheating and adjust if necessary.

Operational Conditions

Once the unit has been operating for
approximately 10 minutes and the
system is stabilized, check the

operational conditions and complete
the following checklist of procedures:

[ ] Check once again the flow of water
and the drops of pressure through the
evaporator and the condenser. These

readings should be stable and at
appropriate levels. If the differential
pressure drops, clean all the water

supply filters.

[ ] Check the suction and discharge

pressures in the unit's pressure
gauges.

Pressures

Take a reading of the discharge

pressure at the connection of the
service valve seat. The suction
pressure levels at the Schrader valve

on the suction line should be as
follows:

Normal pressure levels

Pressures

Normal Values

Discharge

200 to 360 psig

[ ] Check the oil level in the compressors.
At full charge, the oil level should be visible
at the compressor's oil sight glass. If not,
add or remove oil as needed. See table 04
for a list of the types of oil recommended
and the correct amounts for the units.

[ ] Check and record the amperage
consumed by the compressor. Compare
the readings with the compressor's
electrical information shown on its plate.

[ ] Check the liquid sight glass. The flow of
refrigerant should be clean. Bubbles in the
liquid indicate a low charge of refrigerant or
excessive loss of pressure on the liquid
line.
A restriction can frequently be identified by
a notable difference in temperature
between one side and another of the
restricted area. Frequently ice forms at the
outlet of the liquid line at this point too.
Check table XX in this manual.

[ ] Once the oil level, the amperage,
and the operational pressures are
stabilized, measure the superheat.

Read the section on superheat and
subcooling in this manual.

[ ] Measure the subcooling. Read the
section on superheat and subcooling
in this manual.

[ ] If the operational pressure, liquid
sight glass, the superheat, and the

subcooling indicate a lack of
refrigerant gas, add gas to each
circuit. The lack of refrigerant is

indicated if the work pressures are low
and the subcooling is also low.

[ ] Add refrigerant gas (only in the gas
form) with the unit in operation by
adding a gas charge at the Schrader

valve situated on the suction line until
the operational conditions have
normalized.

[ ] If the operational conditions indicate an
overcharge of gas, then slowly remove
refrigerant through the service valve
located on the liquid line. Do not discharge

Operational
Conditions

WARNING!

CAUTION:

In order to minimize the use of the
pressure gauges, close the valves in
order to isolate them after their use.

CAUTION:

The system may not have the right
charge of refrigerant even though the
liquid sight glass is clean. Superheat,

subcooling, and operational pressures
must also be taken into consideration.

CAUTION:

If the suction and discharge pressures
are low but the subcooling is normal,
there is no lack of refrigerant gas. To add

gas would result in overcharge.

CAUTION:

In order to avoid damaging the compres-