YORK INTERNATIONAL 77
FORM 150.40-NM25
DUAL CIRCUIT UNITS
PROBLEM CAUSE SOLUTION
F11 Fault Code 1. Check LWT Cutout Point on Panel. 1. Adjust if necessary, and restart unit.
Low Water (See Page 68.)
Temperature Shutdown 2. Defective LWT or RWT sensor. 2. Check according to following table (use
(Assure the sensor is properly installed digital volt meter)* Replace if necessary.
in the bottom of the well with a
generous amount of heat conductive
compound.)
LWT: J20-1 to J20-3
RWT: J21-1 to J21-3
Low Compressor Oil 1. Low Oil Charge 1. Oil level should be visible in either
Level (Particularly on sight glass at all times. Add YORK
Start-Up.) “C” oil if necessary.
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 o’clock or
8 o’clock position, have good contact
with suction line & be well insulated
from surrounding air.
Crankcase Heater won’t 1. Open in 115VAC wiring to heater 1. Check wiring
Energize (should energize 2. Defective Heater 2. Replace Heater
anytime unit is “OFF”) 3. Auxiliary contacts of Compressor 3. Replace Contactor
(Min. Current draw = Motor Contactor defective.
2 amps)
Temp. °F Volt. -(DC)
30.9 (–0.5°C) 1.67
33.6 (0.9°C) 1.79
36.3 (2.2°C) 1.91
38.9 (3.8°C) 2.03
41.4 (5.2°C) 2.15
43.9 (6.7°C) 2.28
46.4 (8.0°C) 2.40
48.6 (9.2°C) 2.52
50.8 (10.5°C) 2.64
53.0 (11.7°C) 2.76
55.1 (12.8°C) 2.89
57.2 (14.0°C) 3.01
59.3 (15.2°C) 3.13
61.3 (16.3°C) 3.25
63.2 (17.3°C) 3.37
*Check voltage on Combo Board
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