108
AC-SVX003A-EN
Table 31. Diagnostics — main processor (continued)
Diagnostic
Name
Affects Target Severity
Persistence
Active Modes
[Inactive
Modes]
Criteria
Reset
Level
Liquid Line
Pressure Sensor
Circuit Normal Latch All
Bad Sensor or LLID. Note: This is the subcooled liquid line
temp sensor.
Remote
Liquid Line
Temperature
Sensor
Circuit Normal Latch All
Bad Sensor or LLID. Note: This is the subcooled liquid line
temp sensor.
Remote
Loss of Oil for
Compressor
(Running)
Circuit Immediate Latch
Starter Contactor
Energized
In running modes, Oil Loss Level Sensor detects lack of oil
in the oil sump feeding the compressor (distinguishing a
liquid flow from a vapor flow).
Local
Loss of Oil for
Compressor
(Stopped)
Circuit
Immediate
Shutdown and
Special Action
Latch
Compressor Pre-
Start
[all other modes]
In running modes, Oil Loss Level Sensor detects lack of oil
in the oil sump feeding the compressor (distinguishing a
liquid flow from a vapor flow).
Local
Low Differential
Refrigerant
Pressure - xy
Cprsr
Immediate Latch
Cprsr Energized
For startup, please refer to oil flow protection spec. For
running, the system differential pressure for the respective
circuit was below the greater of 25 psid (240.5 kPa) or the
pressure ratio listed in the table in GP2 Compressor Type
FSpec while the compressor is running for a period of time
dependent on the deficit (15 sec ignore time from circuit
start) – refer to the Oil Flow Protection specification for the
time to trip function.
Remote
Low Discharge
Superheat - xy
Cprsr
Normal Latch
Any Running
Mode
While Running Normally, the Compressor Discharge
Superheat CprsrXY was less than the Low Disch Superheat
Trip Setpt CprsrXY for more than (650* Low Discharge
Superheat Setpoint) degree F seconds, for GP2 or more
than (542* Low Discharge Superheat Setpoint) degree F
seconds, for GP4. At circuit startup, the Discharge
Superheat will be ignored for 5 minutes.
Remote
Low Evaporator
Entering Water
Pressure
Chiller Normal Latch All
Evaporator Entering Water Pressure fell below the Low
Evaporator Water Pressure Cutout for more than 30
seconds.
Remote
Low Evaporator
Leaving Water
Pressure
Chiller Normal Latch All
Evaporator Leaving Water Pressure fell below the Low
Evaporator Water Pressure Cutout for more than 30
seconds.
Remote
Low Evaporator
Refrigerant
Temperature
Circuit 1: Unit Off
Chiller
Special Action
NonLatch
Unit in Stop
Mode, or in Auto
Mode and No Ckt
(s) Energized
[Any Ckt
Energized]
The respective circuit’s LERTC Integral was seen to be > 0
while the chiller is in the Stop mode, or in Auto mode with
no compressors running for at least one minute. The
LERTC integral is increased if the Evap Refrigerant Pool
Temp is below the value of the Low Evap Rfgt Temp Cutout
+ 2°F. Energize Evap Water Pump and Off-Cycle Freeze
Avoidance Request Relay until diagnostic auto resets, then
return to normal evap pump control and de-energize the
Freeze Avoidance Request. Automatic reset occurs when
the respective Evap Rfgt Pool Temp rises 4°F(1.1°C) above
the LERTC cutout setting for 1 minute and the Chiller Off
LERTC Integral = 0.. This diagnostic even while active,
does not prevent operation of either circuit.
Remote
Low Evaporator
Refrigerant
Temperature
Circuit 2: Unit Off
Chiller
Special Action
NonLatch
Unit in Stop
Mode, or in Auto
Mode and No Ckt
(s) Energized
[Any Ckt
Energized]
The respective circuit’s LERTC Integral was seen to be > 0
while the chiller is in the Stop mode, or in Auto mode with
no compressors running for at least one minute. The
LERTC integral is increased if the Evap Refrigerant Pool
Temp is below the value of the Low Evap Rfgt Temp Cutout
+ 2°F. Energize Evap Water Pump and Off-Cycle Freeze
Avoidance Request Relay until diagnostic auto resets, then
return to normal evap pump control and de-energize the
Freeze Avoidance Request. Automatic reset occurs when
the respective Evap Rfgt Pool Temp rises 4°F(1.1°C) above
the LERTC cutout setting for 1 minute and the Chiller Off
LERTC Integral = 0.. This diagnostic even while active,
does not prevent operation of either circuit.
Remote
Diagnostics
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