RLC-SVX09Q-EN
81
Table 32. Main processor diagnostics (continued)
Diagnostic
Name
Affects Target Severity
Persistence
Active Modes
[Inactive
Modes]
Criteria
Reset
Level
Low Evaporator
Refrigerant
Pressure - Cktx
Circuit Immediate Latch
Cprsr Prestart
and Cprsr
Energized
a. The Evaporator Pressure (as measured by the cprsr(s)
suction pressure transducers) for the respective circuit,
dropped below 10 Psia just prior to the circuit’s 1st
compressor start (after EXV preposition). b. During Early
Start-up Period: the Evaporator Pressure fell 10 psia. c.
After Early Start-up Period expires: The Evaporator
Pressure fell below 16 Psia.
(Note: the Early Start-up Period is fixed at 3 minutes
relative to the start of the 1st cprsr of the ckt. If ckt is
manifolded, the Evap pressure is defined by the lower of
the two manifolded compressor suction pressures.)
Local
Low Evaporator
Refrigerant
Temperature
Circuit Immediate Latch
All Ckt Running
Modes
The warmer of either the either the Evaporator Refrigerant
Pool Temperature or Active Rfgt Sat Temp for the
respective circuit dropped below the Low Refrigerant
Temperature Cutout Setpoint for 1125ºF-sec (12ºF-sec max
rate for early circuit start-up period) while the circuit was
running. The minimum LRTC setpoint is -5ºF 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.
Local
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
Diagnostics
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