JOHNSON CONTROLS
62
FORM 160.81-NOM1
ISSUE DATE: 10/3/2020
SECTION 5 – MAINTENANCE
DETERMINING CORRECT REFRIGERANT
CHARGE LEVEL
The refrigerant charge level is correct when the mea-
sured evaporator approach and discharge refrigerant
gas superheat are within the values listed in
.
IMPORTANT: The chiller must be at
design operating conditions and full load
operation before the correct refrigerant
charge level can be properly determined.
Liquid refrigerant will be visible in the evaporator
sight glass. The refrigerant level cannot be properly
determined by viewing the liquid refrigerant level in
the evaporator sight glass.
All YR Chillers shipped Form 1 are charged with the
correct amount of refrigerant. Under some operating
conditions the chiller may appear to be overcharged
or undercharged with refrigerant. Consult with the
YORK Factory prior to removing or adding refrig-
erant. The liquid line isolation valve may have to be
partially throttled to prevent overfeeding the evapora-
tor in some applications and under certain operating
conditions.
Definitions:
Evaporator Approach = (S.E.T) - (L.E.L.T)
Discharge Superheat = (C.D.G.T) - (S.C.T)
Where:
S.E.T.
= Saturated Evaporator Temperature
L.E.L.T. = Leaving Evaporator Liquid Temp.
C.D.G.T. = Compressor Discharge Gas Temp.
S.C.T. = Saturated Condensing Temperature
These values can be obtained from the OptiView Con-
trol Center. Refer to
OptiView Control Center – Operat‑
ing and Maintenance (Form 160.81‑O1)
.
REFRIGERANT CHARGING
Should it become necessary to add refrigerant charge
to a YORK YR Chiller; add charge until the evaporator
approach and refrigerant gas discharge superheat are at
within the values listed in
A charging valve is located in the liquid line below the
evaporator. The size of the charging connection is ¾
inch male flare. Purge air and non-condensables from
the charging hose. Only add new refrigerant, or refrig-
erant that has been tested and certified to meet Ameri-
can Refrigeration Institute Standard (ARI-700).
TABLE 17 -
REFRIGERANT CHARGE LEVEL
CONDITION
R-134A REFRIGERANT
COMFORT COOLING APPLICATIONS
Evaporator Approach
1°F-5°F
Discharge Superheat
12°F-18°F
BRINE (ICE MAKING) APPLICATIONS
Evaporator Approach
4°F-8°F
Discharge Superheat
24°F-36°F
REFRIGERANT LEAK CHECKING
Periodic refrigerant leak checking must be part of a
comprehensive maintenance program. Leak check the
entire chiller using a calibrated electronic leak detector.
Use a soap solution to confirm leaks that are found us-
ing the electronic leak detector.
Check refrigerant relief valve piping and tube rolled
joints as part of the comprehensive refrigerant leak
checking program.
Repair leaks before adding refrigerant.
PRESSURE CONNECTIONS
All threaded pressure connections used on the YORK
YR Chillers are SAE straight thread, O-ring face seal
type fittings or Primore Rotalock
®
fittings.
The O-ring straight thread fittings and O-ring face seal
fittings are designed and used in accordance with SAE
J1926 and J1453. Should it become necessary to re-
move a fitting, the O-ring(s) should be replaced. Make
certain to use only neoprene replacement O-rings. O-
rings can be ordered from the local Johnson Controls
Service Office.
Pipe sealant compounds are not required with SAE
type O-ring fittings. The O-ring seal accomplishes the
pressure sealing. Lubricate the O-ring with compressor
oil prior to assembly.
All filter driers and angle shut off valves use Primore
Rotalock
®
fittings. These fittings use a Teflon
®
fiber
seal washer. The Teflon
®
fiber seal washers should be
replaced each time the filter driers are changed.
