50
Table 36 — Alarm and Alert Codes (cont)
*Current imbalance alarm x.25 may be changed to warning x.27 after suc-
cessful start-up of the chiller.
†Compressors are equipped with 2 motor winding temperature thermistors.
Verify first that the problem is not a wiring error before using backup
thermistor.
**Reset automatic first time, manual if repeated on the same date.
††Note that the high-pressure switch should trip before this alert is generated.
Check HPS operation if this alert is generated.
NOTES:
1. Low Oil Pressure Alert Criteria and Set Points
Where: P
d
= Discharge Pressure, P
s
= Suction pressure,
P
o
= Oil pressure and P
e
= Economizer pressure
Two oil pressure set points are used. Oil Set point 1 is always 15 psig.
a. If (P
d -
P
s
) < 125, then Oil Set point 2 = 0.235 x (P
d -
P
s
) + 0.588
b. If (P
d -
P
s
) >= 125 and < 165, then Oil Set point 2 = 2.0 x (P
d -
P
s
) - 220.0
c. If (P
d -
P
s
) >= 165, then Oil Set point 2 = 0.6364 x (P
d -
P
s
) + 5.0
The 2 set points are used by the control for the Low Oil Pressure alert trip
criteria below:
a. Oil Pressure is ignored during the first 5 seconds after a compressor is
started.
b. In period between 5 and 120 seconds after starting, the alert will be gen-
erated if (P
o
- P
e
) < [(Oil Set point 1)/120] x (Compressor Run time in sec-
onds) for 3 consecutive readings
c. After 120 seconds of run time, the alert will be generated if:
1)(P
o
- P
e
) < Oil Set point 1 for 15 seconds OR
2)(P
o
- P
s
) < Oil Set point 2 for 25 seconds
2. (P
o
- P
e
) is the Oil pressure differential displayed in
for Circuit A
and in
for Circuit B.
ALARM/ALERT
CODE
ALARM OR
ALERT
DESCRIPTION
WHY WAS THIS
ALARM GENERATED?
ACTION TAKEN
BY CONTROL
RESET METHOD
PROBABLE
CAUSE
71
Alert
Circuit A Low Oil
Level/Flow
Level switch input open
for 4th time in same day.
Circuit A shut down after
4th failure in 24 hours.
Manual
Low oil level, failed
switch, wiring error,
failed DSIO module
72
Alert
Circuit B Low Oil
Level/Flow
Level switch input open
for 4th time in same day.
Circuit B shut down after
4th failure in 24 hours.
Manual
Low oil level, failed
switch, wiring error,
failed DSIO module
73
Alert
Circuit A Low Discharge
Superheat
Superheat < 5 F (2.8 C)
for 10 minutes
Circuit A shut down
Manual
Faulty thermistor, trans-
ducer, or EXV, or Econo-
mizer. Motor cooling
solenoid stuck open.
74
Alert
Circuit B Low Discharge
Superheat
Superheat < 5 F (2.8 C)
for 10 minutes
Circuit B shut down
Manual
Faulty thermistor, trans-
ducer, or EXV, or Econo-
mizer. Motor cooling
solenoid stuck open.
75
Alarm
Comp. A1 Max. Oil
Delta P, check oil line
(Discharge press - Oil
press) > 100 PSI for
more than 5 seconds
Comp. A1 shut down
Manual
Plugged oil filter, closed
oil valve, bad oil sole-
noid, compressor oil
check valve stuck, oil line
check valve stuck,
plugged oil strainer
76
Alarm
Comp. A2 Max. Oil
Delta P, check oil line
(Discharge press - Oil
press) > 100 PSI for
more than 5 seconds
Comp. A2 shut down
Manual
Plugged oil filter, closed
oil valve, bad oil sole-
noid, compressor oil
check valve stuck, oil line
check valve stuck,
plugged oil strainer
77
Alarm
Comp. B1 Max. Oil
Delta P, check oil line
(Discharge press - Oil
press) > 100 PSI for
more than 5 seconds
Comp. B1 shut down
Manual
Plugged oil filter, closed
oil valve, bad oil sole-
noid, compressor oil
check valve stuck, oil line
check valve stuck,
plugged oil strainer
78
Alarm
Comp. B2 Max. Oil
Delta P, check oil line
(Discharge press - Oil
press) > 100 PSI for
more than 5 seconds
Comp. B2 shut down
Manual
Plugged oil filter, closed
oil valve, bad oil sole-
noid, compressor oil
check valve stuck, oil line
check valve stuck,
plugged oil strainer
79
Alarm
Comp. A1 Failed Oil
Solenoid
Diff. Oil pressure
> 2.5 PSI during period
after oil pump starts and
before oil solenoid opens
Comp. A1 not allowed to
start
Manual
Faulty oil solenoid valve
80
Alarm
Comp. A2 Failed Oil
Solenoid
Diff. Oil pressure
> 2.5 PSI during period
after oil pump starts and
before oil solenoid opens
Comp. A2 not allowed to
start
Manual
Faulty oil solenoid valve
81
Alarm
Comp. B1 Failed Oil
Solenoid
Diff. Oil pressure
> 2.5 PSI during period
after oil pump starts and
before oil solenoid opens
Comp. B1 not allowed to
start
Manual
Faulty oil solenoid valve
82
Alarm
Comp. B2 Failed Oil
Solenoid
Diff. Oil pressure
> 2.5 PSI during period
after oil pump starts and
before oil solenoid opens
Comp. B2 not allowed to
start
Manual
Faulty oil solenoid valve
LEGEND
CCN
— Carrier Comfort Network
CPM
— Compression Protection Module
DGT
— Discharge Gas Temperature
EWT
— Entering Water Temperature
EXV
— Electronic Expansion Valve
FSM
— Flotronic™ System Manager
HPS
— High-Pressure Switch
LCW
— Leaving Chilled Water
LWT
— Leaving Water Temperature
MCT_SP — Maximum Condensing Temperature Set Point
MTA
— Compressor Must Trip Amps
SCT
— Saturated Condensing Temperature
SST
— Saturated Suction Temperature
W/C
— Water-Cooled
WSM
— Water System Manager
