Installation For The First Time; Evacuation Using A Vacuum Pump - Pioneer YN020GMFI22M2D Service Manual

5.4 Installation for the first time:

Air and moisture in the refrigerant system will result
in significant problems with your system:
● Pressure in the system rises.
● Operating current rises.
● Cooling or heating efficiency drops.
● Moisture in the refrigerant circuit may freeze and
block flow through the expansion devices.
● Water when mixed with the refrigerant and oil will
create acid that will damage the motor windings
and components of the compressor.
PROCEDURE FOR DUAL (2) ZONE OUTDOOR
UNITS ARE DIFFERENT FROM OTHERS.
5.4.1. FOR DUAL (2 ZONE SYSTEMS):
Indoor units and the pipes between indoor and
outdoor units must be evacuated and leak tested to
remove trapped air and moisture from the system.
ONE CIRCUIT AT A TIME. This procedure should
start after all electrical connections are finalized and
the system receives proper power for immediate test
running, to be performed one circuit at a time.

Evacuation using a vacuum pump:

1. Completely tighten ALL brass flare nuts, which
connect the ends of copper refrigerant lines to
the attached indoor units and the circuit service
valves on the outdoor unit, using proper torque.
2. Assure that both the 2-way (Liquid) and 3-way
(Gas) valves for each circuit at the outdoor unit
STAY CLOSED as they arrived originally.
3. Connect the low pressure hose on your gauge
manifold (usually blue) to the 3-way (Gas)
valve's service port, belonging to circuit A. Note:
If there is only one indoor unit it should be
connected to circuit A as the primary.
4. If the manifold gauge set's hoses have 1/4" SAE
connections, a 1/4" to 5/16" SAE port adapter will
be needed. (Sold separately).
5. Connect the center hose of the gauge manifold
(usually yellow) to the vacuum pump.
6. Fully open the Low side valve on the low
pressure side of your gauge manifold. Assure
that the High side valve on the high pressure
side of your gauge manifold stays closed.
7. Start the vacuum pump and operate according to
pump manufacturer's specifications. If your
vacuum pump has a valve, open it as well.
8. Perform vacuuming / evacuation for a minimum
period of 30 minutes and check that the low
pressure gauge indicates a vacuum of 30 in/hg
(500 microns). (A more sensitive vacuum gauge
should be used if available).
9. If the proper vacuum cannot be achieved within
30 minutes, the vacuum pump should be kept
running for an additional 15 minutes. If after the
additional 15 minutes of operation, the vacuum
still cannot be achieved, there could be a leak at
one or more of the flare pipe connections at
either end of a refrigerant pipes. Leak must be
located and the leaking nut must be tightened
properly before re-vacuuming the circuit.
10. If the vacuum is achieved, close the low side
valve at the low pressure side on your gauge
manifold first and shut the vacuum pump off.
Leave the gauge manifold set and the hoses
connected and recheck the vacuum reading 15
minutes later to assure there is no vacuum loss.
(Very small increase in vacuum level is normal).
11. Circuit A is now dry and free of contaminants. Do
not remove the hose of your gauge manifold set
from the service port.
12. Remove the 2-way (Liquid) Valve's brass dust
cap of circuit A. Insert proper size Allen wrench
into the valve core and turn it counter clockwise
for 1 turn for, wait for 3 seconds and quickly close
the valve by turning it in reverse direction. Check
your low pressure gauge on the manifold to
assure it now indicates positive pressure of
approximately 80 to 120 PSI in your lines.
13. Apply soap-water mixture on both the indoor unit
connections and the outdoor unit connections for
circuit A with a soft brush to check for leakage at
the connecting points of the piping. If you notice
air bubbles, the specific connector has leakage
and must be tightened to stop the leakage.