YORK INTERNATIONAL
33
FORM 150.40-NM25
SINGLE CIRCUIT UNITS
VERIFYING PROPER CUT-OUT SETPOINTS AND HOW TO ADJUST THEM IF NEEDED
CHECKING THE SYSTEM 24 HOURS PRIOR TO INI-
TIAL START-UP (NO POWER)
1. Unit Checks
A. Inspect the unit for shipping or installation damage.
B. Assure that all piping has been completed.
C. Check that the unit is properly charged and that
there are no piping leaks.
D. Suction and discharge stop valves and the refriger-
ant liquid stop valves are open (ccw).
CAUTION: Compressor lubrication circuit must be
primed with YORK “C” oil prior to start-up.
Priming should be done through the
Schrader fitting at the compressor oil pump
Stroke oil pump 10 times to prime the lubrica-
tion circuit.
E. The compressor oil level must be maintained be-
tween the middle of the upper and middle of the
lower sight glass at all operating conditions. At part
load operating conditions, it is not abnormal for the
Three cut-outs are adjustable and proper adjustment
should be verified when starting up a chiller. These cut-
outs are Low Ambient Cut-Out, Low Suction Pressure
Cut-Out, and Low Water Temp. Cut-Out.
Low Ambient Cut-Out
This cut-out is factory set at 35°F (1.7°C) by placing SW2
(page 31 & 32) of the Micro Logic Board to the OFF
position. This should never be changed unless a Low
Ambient Kit is installed on an air cooled chiller.
A Low Ambient Kit will require the cut-out setting to typi-
cally be set lower than 35°F (1.7°C). To do this place
SW2 (page 31 & 32) of the Micro Logic Board to the ON
position and adjust R1 of the Combo Board (Fig. 27)
while viewing the Low Ambient Cut-out display (0,7). The
cutout is adjustable from 0 to 50°F (–17.8 to 10°C).
Low Suction Pressure Cut-Out
This cut-out is factory set at 44 PSI (303 kPa). This
should never be changed unless brine or glycol is added
to the system. When brine or glycol is added, lower the
low pressure cut-out according to concentration by
adjusting R3 on the Combo Board (Fig. 52). The cutout
can be adjusted from 10-59 PSI (68.9-406.5 kPa), while
viewing the Low Pressure Cut-Out Display (1, 6).
Low Water Temp. Cut-Out
The low water temp. cut-out is factory set at 36°F (2.2°C).
This should never be changed unless brine or glycol is
added to the system. When brine or glycol is present,
the cut-out can be lowered according to concentration
by adjusting R2 of the Combo Board (Fig. 27) while view-
ing the Low Water Temp. Cut-out display (0, 4).
RELAY OUTPUT BOARD JUMPERS
Jumpers J34 and J35 must be in the “C” position. Other-
wise fan operation will be incorrect and high pressure
faulting will result.
FIG. 27 – LOCATION OF R1, R2 & R3 ON COMBO
BOARD
LD01626
SYSTEM START-UP AND OPERATION
oil level to be in the lower sight glass. If it is neces-
sary to add oil, connect a YORK oil pump to the oil
charging valve, but do not tighten the flare nut on
the delivery tubing. With the bottom (suction end)
of the pump submerged in oil to avoid the entrance
of air, operate the pump until oil drips from the flare
nut joint, allowing the air to be expelled, and tighten
the flare nut. Open the compressor oil charging
valve and pump in oil until the oil reaches the proper
level as described above. Close the compressor
oil charging valve.
F. Assure water pumps are on. Check and adjust wa-
ter pump flow rate and pressure drop across cooler.
G. Check panel to see that it is free of foreign material
(wires, metal chips, etc.).
H. Visually inspect wiring (power & control). Must meet
NEC and all local codes.*,**
I. Check for proper size fuses in main and control
power circuits.
*See pg. 7.
**See pg. 9.
