JOHNSON CONTROLS
188
FORM 150.67-NM2 (209)
Service and Troubleshooting
PROBLEM
CAUSE
SOLUTION
“MP / HPCO” FAULT
1. Compressor internal motor
1. Verify refrigerant charge is
protector (MP) open.
not low. Verify superheat
setting of °10 – 15 °F (5.6° –
8. 3 °C). Verify correct com-
pressor rotation. Verify
compressor is not over
loaded.
2. External overload tripped.
2. Determine cause and reset.
3. HPCO switch open.
3. See “High Press. Disch.”
Fault.
4. Defective HPCO switch.
4. Replace HPCO switch.
5. Defective CR relay.
5. Replace relay.
COMPRESSOR(S) WON’T
1. Demand not great enough.
1. No problem. Consult
START
“Installation” Manual to aid
in
understanding
compres-
sor operation and capacity
control.
2. Defective water temperature
2. Compare the display with a
sensor.
thermometer. Should be
/- 2 degrees. Refer
to Service section for RWT/
LWT
temp./voltage
table.
3. Contactor/Overload failure.
3. Replace defective part.
4. Compressor failure.
4. Diagnose cause of failure
and
replace.
LACK OF COOLING EFFECT
1. Fouled evaporator surface.
1. Contact the local YORK
Low suction pressure will
service representative.
be
observed.
2.
Improper
fl ow through the
2. Reduce fl ow to within chiller
evaporator.
design specs. See Limita-
tions in Installation section.
3. Low refrigerant charge.
3. Check subcooling and add
Low suction pressure will
charge as needed.
be
observed.
TROUBLESHOOTING (CONT’D)
Summary of Contents for YCAL0019
Page 55: ...FORM 150 67 NM2 209 55 JOHNSON CONTROLS 5 5 ELEMENTARY WIRING DIAGRAM CON T LD12699D...
Page 57: ...FORM 150 67 NM2 209 57 JOHNSON CONTROLS 5 5 ELEMENTARY WIRING DIAGRAM CON T LD12693C...
Page 59: ...FORM 150 67 NM2 209 59 JOHNSON CONTROLS 5 5 ELEMENTARY WIRING DIAGRAM CON T LD 12198...
Page 61: ...FORM 150 67 NM2 209 61 JOHNSON CONTROLS 5 5 LD12702 ELEMENTARY WIRING DIAGRAM CON T...
Page 63: ...FORM 150 67 NM2 209 63 JOHNSON CONTROLS 5 5 LD12696 ELEMENTARY WIRING DIAGRAM CON T...
Page 65: ...FORM 150 67 NM2 209 65 JOHNSON CONTROLS 5 5 CONNECTION WIRING DIAGRAM CON T LD12703B...
Page 67: ...FORM 150 67 NM2 209 67 JOHNSON CONTROLS 5 5 CONNECTION WIRING DIAGRAM CON T LD12697B...
