Diagnostics
76
RTAF-SVX001A-EN
Low Differential
Refrigerant
Pressure - xy
Low Differential
RfgtPressure -
xy
Low Diff Rfgt
Press - xy
Cprsr
Immediate Latch
Cprsr
Energized
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 Discharge Superheat was less than the
Low Discharge Superheat Setpoint for more than 6500 degree F
seconds. At circuit startup, the Discharge Superheat will be ignored for
5 minutes.
Remote
Low Evaporator
Temp: Circuit 1:
Unit Off
Low Evaporator
Temp: Ckt 1:
Unit Off
Low Evap Temp:
Unit Off
Evap
Pump
Special
Action
NonLatch
Unit in Stop
Mode, or in
Auto Mode
and No Ckt's
Energzd [Any
Ckt Energzd]
The respective circuit’s LERTC Integral was seen to be higher than ½
of its trip value (1,125°F-sec) 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 4°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 2°F (1.1°C) above the LERTC
cutout setting and the Chiller Off LERTC Integral is less than 1/3 of its
trip value. This diagnostic even while active, does not prevent operation
of either circuit.
Remote
Low Evaporator
Temp: Circuit 2:
Unit Off
Low Evaporator
Temp: Ckt 2:
Unit Off
Low Evap Temp:
Unit Off
Evap
Pump
Special
Action
NonLatch
Unit in Stop
Mode, or in
Auto Mode
and No Ckt's
Energzd [Any
Ckt Energzd]
The respective circuit’s LERTC Integral was seen to be higher than ½
of its trip value (1,125°F-sec) 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 4°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 2°F (1.1°C) above the LERTC
cutout setting and the Chiller Off LERTC Integral is less than 1/3 of its
trip value. This diagnostic even while active, does not prevent operation
of either circuit.
Remote
Low Evaporator
Water Temp
(Unit Off)
Low Evap Water
Temp-Unit Off
Evap
Pump
and
Freeze
Avoidanc
e
Request
Relay
Special
Action
NonLatch
Unit in Stop
Mode, or in
Auto Mode
and No Ckt(s)
Energzd [Any
Ckt Energzd]
Either the entering or leaving evaporator water temp. fell below the
leaving water temp cutout setting for 30 degree F seconds while the
Chiller is in the Stop mode, or in Auto mode with no compressors
running. Energize Freeze Avoidance Request Relay and Evap Water
Pump Relay until diagnostic auto resets, then de-energize the Freeze
Avoidance Request Relay and return to normal evap pump control.
Automatic reset occurs when both temps rise 2°F (1.1°C) above the
cutout setting for 5 minutes, or either circuit starts. This diagnostic
even while active, does not prevent operation of either circuit.
Remote
Low Evaporator
Water Temp
(Unit On)
Low Evap Water
Temp-Unit On
Chiller
Immediate
and Special
Action
NonLatch
Any Ckt[s]
Energzd [No
Ckt(s)
Energzd]
The evaporator entering or leaving water temperature fell below cutout
setpoint for 30 degree F Seconds while the compressor was running.
Automatic reset occurs when both of the temperature rises 2°F (1.1°C)
above the cutout setting for 2 minutes. This diagnostic shall not de-
energize the Evaporator Water Pump Output.
Remote
Low Oil Flow - xy Cprsr
Immediate Latch
Cprsr
Energized and
Delta P above
15 Psid
The intermediate oil pressure sensor for this compressor was out of the
acceptable pressure range for 15 seconds, while the Delta Pressure was
greater than 15 Psid (172.4 kPa).: Acceptable range is 0.50 > (PC-PI)
/ (PC-PE) for the first 2.5 minutes of operation, and 0.28 > (PC-PI) /
(PC-PE) thereafter.
Local
Low Refrigerant
Temperature
Circuit
Immediate Latch
All Ckt
Running
Modes
The respective Evaporator Refrigerant Pool Temperature dropped below
the Low Refrigerant Temperature Cutout Setpoint for 2250°F-sec
(12°F-sec max rate for early circuit startup period) while the circuit was
running. The minimum LRTC setpoint is -5°F (18.7 Psia) the point at
which oil separates from the refrigerant. The integral is held nonvolatile
though power down, is continuously calculated, and can decay or build
during the circuit off cycle as conditions warrant.
Remote
Table 27.
Main processor diagnostics (continued)
Diagnostic
Name
Affects
Target Severity Persistence
Active
Modes
[Inactive
Modes]
Criteria
Reset
Level
