York YLAA0041 Manual page 112

SECTION 6 – COMMISSIONING
However, sometimes the system can run without enough
refrigerant in it. If you have no idea how much refriger-
ant is inside of the system, then follow the steps below.
1. Connect the charging hose between the refrigerant
tank and the angle valve at the inlet of evaporator.
Exclude the air inside of hose.
2. Put the refrigerant tank on a scale and read the ini-
tial weight. Leave the tank on scale until process
is complete.
3. Get as many compressors running as the system
permits.
4. Open the angle valve 1.5 turns.
5. Open the valve on the tank.
Quickly shut down the angle valve or
the tank valve immediately if all of com-
pressors stop suddenly in the process of
charging.
6. Monitor the suction superheat (SH) and liquid
subcooling (SC). If SH is around 10R and SC>6R,
close the angle valve. Wait at least 15 min.
7. If SC<10R or SH>10R always, continue to charge
the system. Open the angle valve 1.5 turns. Close
it after one pound is added. Wait another 15 min.
Repeat this step until both SC and SH are around
10R with all of the fans and compressors running.
8. Close the angle valve and tank valve. Disconnect
the hose.
Service and Oil Line Valves
Open each compressor suction, economizer, and dis-
charge service valve. If valves are of the back-seat
type, open them fully (counterclockwise) then close
one turn of the stem to ensure operating pressure is fed
to pressure transducers. Open the liquid line service
valve and oil return line ball valve fully in each system.
Fans
Check that all fans are free to rotate and are not dam-
aged. Ensure blades are at the same height when ro-
tated. Ensure fan guards are securely fixed.
Temperature Sensor(s)
Ensure that the leaving liquid temperature sensor is
coated with heat conductive compound (Part No. 013-
00890-000) and is inserted to the bottom of the water
outlet sensor well in the cooler. This sensor also pro-
vides some freeze protection and must always be fully
inserted in the water outlet sensor well.
112
Compressor Heaters
Verify the compressor heaters are energized. If the am-
bient temperature is above 96°F (36°C) the compressor
heaters must be on for at least 8 hours before start-up
to ensure all refrigerant liquid is driven out of the com-
pressor and the oil. If the ambient temperature is below
86°F (30°C), allow 24 hours.
Power Connections
Check that the customer power cables are connected
correctly to the terminal blocks or optional circuit break-
er. Ensure that connections of power cables within the
panels to the circuit breaker or terminal blocks are tight.
Grounding
Verify that the unit's protective ground terminals are
correctly connected to a suitable grounding point. En-
sure that all unit internal ground connections are tight.
Compressor Oil
To add oil to a circuit, complete the following steps:
1. Connect a Johnson Controls hand oil pump
(P/N 470-10654-000) to the 1/4 in. oil charging
connection on the compressors with a length of
clean hose or copper line, but do not tighten the
flare nut.
2. Pump the oil until all air has been purged from the
hose, then tighten the nut.
3. Stroke the oil pump to add oil to the oil system.
Approximately 1.8 gal to 2.3 gal is present in each
refrigerant system.
Oil levels in the oil equalizing line sight glass should
be between the bottom and the middle of the sight glass
with the system OFF. When running, a visible sign of
oil splashing in the sight glass in normal.
High oil levels may cause excessive oil
carryover in the system. High oil concen-
tration in the system may cause nuisance
trips resulting from incorrect readings on
the level sensor and temperature sensors.
Temperature sensor errors may result in
poor liquid control and resultant liquid
overfeed and subsequent damage to the
compressor.
For Copeland compressors, use YORK V
oil, YORK P/N 011-00949-000.
For Bitzer compressors, use YORK PVE
oil, YORK P/N 011-00982-000.
FORM 150.72-ICOM6
ISSUE DATE: 08/03/2022
JOHNSON CONTROLS