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)
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