Vertiv Liebert DSE - Page 41

1. Starting with Circuit #1, open the service valves and place a 150 PSIG (1034kPa) of dry
nitrogen with a tracer of refrigerant. Check system for leaks with a suitable leak detector.
2. With pressure still in Circuit #1, open the compressor service valves in Circuit#2.
• If pressure increases in Circuit#2, the system is cross-circuited and must be re-checked
for proper piping.
• If there is no pressure increase, repeat step1 on Circuit#2.
3. After completion of leak testing, release the test pressure, (observe local code) and pull an
initial deep vacuum of 500microns on the system with a suitable pump.
4. After 4hours, check the pressure readings and, if they have not changed, break vacuum with
dry nitrogen. Pull a second and third vacuum to 500 microns or less. Re-check the pressure
after 2hours.
When the 3 checks are complete, remove the jumper hose from the service-valve fitting and
the condenser, and proceed to Charging Air-cooled Systems below.
Charging Air-cooled Systems
NOTICE
Risk of improper refrigerant charging. Can cause equipment damage.
R-410A is a blended refrigerant and must be introduced and charged from the cylinder only as
a liquid.
When adding liquid refrigerant to an operating system, it may be necessary to add the
refrigerant through the compressor suction service valve.service . Care must be exercised to
avoid damage to the compressor. We recommend connecting a sight glass between the
charging hose and the compressor suction service valve. This will permit adjustment of the
cylinder hand valve so that liquid can leave the cylinder while allowing vapor to enter the
compressor.
NOTICE
Risk of improper operation. Can cause compressor failure.
Operating the unit with the EEV closed can cause compressor failure. The reheat and
humidifier are disabled. A minimum of 20 psig (138 kPa) must be established and maintained
for the compressor to operate. The charging function can be reset as many times as required
to complete
To calculate the charge for the system:
1. Check the nameplate on the indoor unit for refrigerant type to be used. Unit control
configurations differ depending on refrigerant type.
2. The unit must be operating, refer to Checklist for Completed Installation on page49, the
"Liebert® MC™ Installer/User Guide," and "Liebert® EconoPhase™ Installer/User Guide."
3. Calculate the amount of charge for the system. See Refrigerant Charge Requirements for
Air-cooled Systems on page37.
4. Accurately weigh in as much of the system charge as possible before starting the unit. Do not
exceed the calculated charge by more than 0.5lb(0.37kg).
5. Close the Liebert® MC and Liebert® EconoPhase disconnect switches.
• We recommend charging the unit with the return-air setpoint between 75°F and 85°F
(24°C and 29°C).
• The return-air temperature to the unit being charged must be stable and must be
maintained greater than 65°F(18°C). If this is not possible due to lack of heat load, then
the load banks must be used to offset the cooling load during start-up. See
Refrigerant-level Sight Glasses ontheReceiver on the next page.
5 Piping and Refrigerant Requirements 41