Charge Isolation In The High Or Low Side Of System - Trane R Series Installation Operation & Maintenance

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Maintenance Procedures
Adding charge:
This procedure should be followed
when adding charge to an
undercharged unit. When low
charge is indicated by low
subcooling in the liquid line, charge
should be added until sufficient
subcooling is achieved.
1. Attach the charging hose to the
evaporator service valve (3/8"
[9 mm] flare). Open the service
valve.
2. Add 4.5 kg of refrigerant (R-134a)
charge.
3. Close the valve, remove the
charging hose and start the unit.
Monitor subcooling.
4. If subcooling is still insufficient,
return to step number 1.
Note: Proper subcooling can be
determined from run-log history,
service experience, or by contacting
Trane technical service.
The service tool may include a
calculation module that determines
the proper subcooling for any
operating condition (Trane Service
only).
Charge Isolation in the
high or low side of the
system
(only possible with optional
isolating valves)
All the refrigerant may be trapped
into the high side (condenser) of the
unit for maintenance on the
compressor (or low side). With the
suction-line service valve option,
charge may also be isolated in the
evaporator for maintenance on the
compressor (or high side). It is
much more preferable to isolate the
charge in the evaporator, if this
option is available.
High side charge isolation
procedure:
1. Make sure the circuit is off.
2. Shut the liquid-line service valve.
3. Shut the oil return-line service
valve.
4. Start the circuit with the service
tool in charge-isolation mode:
• All fans will turn on
• EXV will open 100%
• The oil return-line solenoid, if
included, will open
• The unit will start at minimum
load
• The unit will run until it cuts out
on low pressure (~6 psia) [0.41
bar].
5. When the unit trips, the discharge
check valve and the oil-line
shutoff valve close.
6. Close the discharge isolation
valve.
7. Close the oil-line shutoff valve.
8. Remove the remainder of the
charge with the vacuum pump.
Recommendation: Do not pump
the remaining charge into the
high side. This may introduce
non-condensable gasses and
other contaminants into the unit.
9. The low side and the compressor
may be serviced at this time.
RLC-SVX02G-E4