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D D i i a a g g n n o o s s t t i i c c s s
Table 27. Diagnostics — main processor (continued)
Affects
Diagnostic
Target
Name
Low
Evaporator
Circuit
Rfgt Pressure -
Ckt2
Low
Evaporator
Rfgt
Circuit
Temperature -
Ckt1
Low
Evaporator
Rfgt
Circuit
Temperature -
Ckt2
Low
Evaporator
Evap Pump
Temp (Unit Off)
– Ckt1
94
Severity
Persistence
Immediate
Latch
Immediate
Latch
Immediate
Latch
Info and
NonLatch
Special Action
Active
Modes
[Inactive
Modes]
a. The Evap Refrig Pressure dropped below 10 Psia
just prior to compressor start (after EXV
preposition). b. During Early Startup Period: the
Evap Refrig Pressure fell below a pressure equal to
Cprsr Prestart
Condenser Pressure ÷ 8 but as limited to not less
and Cprsr
than 6 or greater than 10 psia. c. After Early Startup
Energized
Period expires: The Evap Refrig Pressure fell below
16 Psia for 30 seconds or below 10 psia for 5
seconds. (Note: the Early Startup Period for RTAE it
is between 1 and 5 min as an inverse function of the
Cond Temp measured at time of circuit startup)
The warmer of either the Evaporator Refrigerant Pool
Temperature or the Evaporator Saturated
Temperature for the respective circuit, dropped
below the Low Refrigerant Temperature Cutout
All Ckt Running
Setpoint for 2250 F-sec (12 F-sec/sec max rate
Modes [Service
for early circuit startup period) while the circuit was
Pumpdown]
running. The minimum LERTC setpoint is -5 F the
point at which oil separates from the refrigerant. The
integral is held nonvolatily though power down, is
continuously calculated, and can decay or build
during the circuit's off cycle as conditions warrant
The warmer of either the Evaporator Refrigerant Pool
Temperature or the Evaporator Saturated
Temperature for the respective circuit, dropped
below the Low Refrigerant Temperature Cutout
All Ckt Running
Setpoint for 2250 F-sec (12 F-sec/sec max rate
Modes [Service
for early circuit startup period) while the circuit was
Pumpdown]
running. The minimum LERTC setpoint is -5 F the
point at which oil separates from the refrigerant. The
integral is held nonvolatily though power down, is
continuously calculated, and can decay or build
during the circuit's off cycle as conditions warrant.
The respective circuit's "Chiller Off Cycle Freeze
Protection Integral" was seen to be higher than ½ of
its trip value while the chiller is in the Stop mode, or
in Auto mode with no compressors running, for one
minute and more. The COCFP integral is increased if
the Average of the Evap Water Temperature and the
Evap Refrigerant Pool Temp is below the value of the
Unit in Stop
Low Evap Rfgt Temp Cutout + 4°F. Energize Evap
Mode, or in
Water Pump and Off-Cycle Freeze Avoidance Request
Auto Mode and
Relay until diagnostic auto resets, then return to
No Ckt's
normal evap pump control and de-energize the
Energzd [Any
Freeze Avoidance Request. Automatic reset occurs
Ckt Energzd]
when the respective Evap Rfgt Pool Temp rises 2 F
(1.1 C) above the LERTC cutout setting and the
COCFP Integral is less than 1/3 of its trip value. This
diagnostic even while active, does not prevent
operation of either circuit. (At each circuit shutdown,
the COCFP integral is initialized to the LERTC
Criteria
integral)
AC-SVX001A-EN
Reset
Level
Local
Remote
Remote
Remote
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