Refrigerant Charging; Checking The Refrigerant Charge During Unit Shutdown; Figure 12 - Saturation Curve; Figure 13 - Diagram, Megging Motor Windings - York R-134a Operation And Maintenance Manual

SECTION 6 - MAINTENANCE

FIGURE 12 - SATURATION CURVE

REFRIGERANT CHARGING

To avoid the possibility of freezing liquid within the
evaporator tubes when charging an evacuated system,
only refrigerant vapor from the top of the drum or cyl-
inder must be admitted to the system pressure until the
system pressure is raised above the point correspond-
ing to the freezing point of the evaporator liquid.
While charging, every precaution must be taken to pre-
vent moisture laden air from entering the system. Make
up a suitable charging connection from new copper tub-
ing to fit between the system charging valve and the fit-
ting on the charging drum. This connection should be
as short as possible but long enough to permit sufficient
flexibility for changing drums. The charging connection
MAIN DISCONNECT
(OPEN)

FIGURE 13 - DIAGRAM, MEGGING MOTOR WINDINGS

26
TIME
LD00474
STARTER (OPEN)
should be purged each time a full container of refriger-
ant is connected and changing containers should be done
as quickly as possible to minimize the loss of refrigerant.
Refrigerant may be furnished in cylinders containing
either 30, 50, 125, 1,025, or 1750 lb. (13.6, 22.6, 56.6,
464, or 794 kg) of refrigerant.
The nameplate on the chiller contains the
correct refrigerant charge information
for the chiller.
CHECKING THE REFRIGERANT CHARGE
DURING UNIT SHUTDOWN
The refrigerant charge is specified for each chiller model.
Charge the correct amount of refrigerant and record the
level in the evaporator sight glass.
The refrigerant charge should always be checked and
trimmed when the system is shut down.
The refrigerant charge level must be checked after the
pressure and temperature have equalized between the
condenser and evaporator. This would be expected to be
4 hours or more after the compressor and water pumps
are stopped. The level should be visible in the sight glass.
Charge the refrigerant in accordance with the meth-
od shown under the REFRIGERANT CHARGING,
above. The refrigerant level should be observed and
the level recorded after initial charging.
MEGOHM
BETWEEN
WINDINGS
MEGOHM METER
FORM 160.76-O1
ISSUE DATE: 05/22/2019
MEGOHM
METER
MEGOHM EACH
WINDING TO GROUND
LD00475
JOHNSON CONTROLS