LG Multi V Water IV - Pre-Commissioning: Vacuum Water Source Systems; Vacuuming Water Source Systems; Heat Pump System Vacuum Configuration Diagram

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MULTI V Water IV System Installation Manual
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PRE-COMMISSIONING
Prepare the Refrigerant Piping System
Vacuum for Water Source Systems
Vacuum the refrigerant piping system by connecting the vacuum pump to the service ports on the water source unit as shown in Figure 85
for heat pump systems and Figure 86 for heat recovery systems. Use a vacuum pump with a gauge that can evacuate to 500 microns, and
vacuum with the service port valve closed. Never air purge with refrigerant.
1. Evacuate the system for two (2) hours, bringing the system up to 500 microns. After maintaining the system to 500 microns for more than
one (1) hour, confirm that pressure has risen. If not, there may be moisture or a leak somewhere in the refrigerant piping system.
2. If the system has been evacuated for more than two (2) hours and it is suspected that moisture may be present (rainwater may have en-
tered the piping if installation look a long time to complete, or if work occurred during a rainy season), pressurize to 14 psi (vacuum break)
with nitrogen gas, and then vacuum again for one (1) hour to 500 microns. If the system cannot be evacuated to 500 microns within two
(2) hours, repeat vacuum break. After maintaining the system in vacuum for one (1) hour, check the vacuum gauge to see if pressure has
risen.
Indoor Unit
Slave WSU Master WSU
Liquid Pipe
Vapor Pipe
Liquid Side
Vapor Side
Close
WSU
Valve
Close
WSU
Valve
Close
WSU
Valve
Close
WSU
Valve
Vacuum
Pump
Connect
Gauges to
Schrader
Valves
Figure 85: Heat Pump System Vacuum Conguration