Final Installation Procedures - LG MULTI F Installation Manual

FINAL INSTALLATION PROCEDURES

After the refrigerant piping installation is complete, perform a triple leak / pressure test. Triple leak / pressure test is performed between the
outdoor unit and indoor units (and branch distribution units [Multi F MAX only]) to verify that refrigerant can flow through the system without
danger of leaks or pressure losses. Air and moisture that is left in the piping can lead to undesirable results and can cause damage to the
system. It is important to go through a complete leak / pressure cycle to be sure that the refrigerant piping is cleared out. This process will
have to be repeated if any air or moisture be is found to remain in the piping.
• Pressure in the system can rise.
• Operating current can rise.
• Inefficient cooling or heating mode capability.
DANGER
gen) when checking leaks, cleaning, installing/repairing pipes, etc. The use of at least 800 psig nitrogen regulator is required for safety.
• Do not apply power to the system before performing a system leak test. There is a possibility that the EEV valve will close and isolate
sections of the piping system, making the leak test inconclusive.
• Never perform the leak test using refrigerant.
• To avoid nitrogen entering the refrigerant system in a liquid state, the top of the cylinder must be higher than its bottom (used in a vertical
standing position) when the system is pressurized.
• Use only a leak-free gauge manifold set.
• Piping system must not be pressured to more than 550 psi. Pressures greater than 550 psi will damage the piping system and cause unit
malfunction.
Triple Leak / Pressure Check Procedure
1. After the refrigerant piping installation is complete, open the isolation ball valves, if
any, that could have been included in the piping system.
2. Verify that both the liquid and gas (vapor) suction line outdoor unit service ports are
closed, and the stem head access caps are tight. The leak / pressure check is to be
performed only to the refrigerant piping system, and all connected indoor units and
branch distribution units (Multi F MAX units only).
3. Remove the caps on both the liquid and gas (vapor) suction Schrader ports. Con-
nect the (medical-grade dry) nitrogen cylinder regulator to a gauge manifold, then
connect the gauge manifold to the Schrader ports on the service ports.
4. Perform the leak / pressure check at 150 psig for fifteen (15) minutes (standing
pressure check).
5. Perform the leak / pressure check at 300 psig for thirty (30) minutes (standing
pressure check).
6. Perform the leak / pressure check at 550 psig for one (1) hour to make sure the
piping system is leak-free. After the gauge reading reaches 550 psig, isolate the
system by first closing the gauge manifold, then close the nitrogen cylinder valve.
Check the flared (and any brazed connections) for leaks by applying a bubble
solution to all joints. Also test for leaks at both service valves.
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• Moisture in the refrigerant circuit will freeze and block capillary
tubing.
• Water can lead to corrosion of parts in the system.
Figure 98: Triple Leak / Pressure Test Diagram.
Outdoor Unit
Appearances will vary depending on model.
F
MULTI
F
MULTI MAX
Indoor Units
Manifold Valve
Pressure
Gauge
Lo Hi
Charge Hose
Nitrogen Gas
Cylinder (with
cylinder upright)
Service Ports
-