FORM 150.60-NM4
YORK INTERNATIONAL
89
PROBLEM
CAUSE
SOLUTION
Chiller Fault: Low
1. RWT Control ONLY: Control range is
1. Flow is lower than design. Increase flow
Water Temp
too small and does not match actual
or increase the control range to match
Low water
∆
T across evaporator under full load
actual evaporator
∆
T.
temperature
conditions.
shutdown.
2. Check LWT cut-out point on panel.
2. Adjust if necessary, and restart unit.
(See Page 37).
3. Defective LWT or RWT sensor.
3. Check according to following table (use
(Assure the sensor is properly
digital volt meter)* Replace if necessary.
installed in the bottom of the well
with a generous amount of heat
TEMP
VOLTAGE (DC)
conductive compound.
20.0°F
1.65
22.0°F
1.71
NOTE: It is not unusual to find up to
25.0°F
1.82
a +2°F difference between
27.0°F
1.88
the display and a
30.0°F
1.99
thermometer located in
33.0°F
2.09
waterpiping.
36.0°F
2.22
38.0°F
2.28
41.0°F
2.37
43.0°F
2.43
46.0°F
2.54
48.0°F
2.60
50.0°F
2.67
53.0°F
2.77
55.0°F
2.83
57.0°F
2.89
59.0°F
2.95
61.0°F
3.02
63.0°F
3.08
65.0°F
3.14
67.0°F
3.20
70.0°F
3.28
* Check voltage on Microprocessor Board.
LWT: J11-7 to J11-1
RWT: J11-8 to J11-1
Low Compressor
1. Low oil charge.
1. Oil level should be visible in sight glass
Oil Level
at all times. Add YORK C oil if
(Particularly on
necessary.
start-up)
2. Excessive flood back of liquid
2. Adjust Thermal Expansion Valve (TXV)
refrigerant.
or replace power element. Check TXV
bulb location. Should be located on
suction line at least 8"-10" from nearest
elbow. Bulb should be at 4 oclock or 8
oclock position, have good contact with
suction line and be well insulated.
Crankcase Heater
1. Open in 115VAC wiring to heater.
1. Check wiring.
wont Energize
2. Defective heater.
2. Replace heater.
(Should energize an-
3. Auxilliary contacts of compressor
3. Replace contactor.
time unit is OFF)
contactor defective.
(Min. current draw = 2
amps)
