Diagnostics
RTAC-SVX01J-EN 155
Evaporator Entering
Water Temperature
Sensor
Chilled
Water
Reset
Info Latch All
Bad Sensor or LLID a. Normal operation, no effects on control.
b. Chiller shall remove any Return or Constant Return Chilled
Water Reset, if it was in effect. Apply slew rates per Chilled
Water Reset spec.
Remote
Evaporator Leaving
Water Temperature
Sensor
Chiller Normal Latch All Bad Sensor or LLID Remote
Evaporator Liquid
Level Sensor -
Circuit 1
Circuit Immediate Latch All Bad Sensor or LLID Remote
Evaporator Liquid
Level Sensor -
Circuit 2
Circuit Immediate Latch All Bad Sensor or LLID Remote
Evaporator Rfgt
Drain - Circuit 1
Circuit NA Latch
Circuit non-
running modes
[Drain Valve
commanded
closed]
This diagnostic is effective only with Remote Evap units. The
liquid level of the respective evaporator was not seen to be below
the level of -21.2 mm within 5 minutes of the commanded
opening of its Drain Valve Solenoid. The diagnostic will not be
active if the drain valve is commanded closed.
Remote
Evaporator Rfgt
Drain - Circuit 2
Circuit NA Latch
Circuit non-
running modes
[Drain Valve
commanded
closed]
This diagnostic is effective only with Remote Evap units. The
liquid level of the respective evaporator was not seen to be below
the level of -21.2 mm within 5 minutes of the commanded
opening of its Drain Valve Solenoid Valve. The diagnostic will not
be active if the drain valve is commanded closed.
Remote
Evaporator Water
Flow (Entering
Water Temp)
Chiller
Immediate
Shutdown
Latching
Any Ckt Energized
[No Ckts
Energized]
The entering evaporator water temp fell below the leaving
evaporator water temp by more than 2 F for 180 F-sec,
minimum trip time 1 minute.
Remote
Evaporator Water
Flow (High Approach
Temperature)-
Circuit 1
Chiller
Immediate
Shutdown
Latching
Ckt Energized
[Ckt Not
Energized]
Large evaporator approach temps, low evap sat temps, and
presence of liquid refrigerant, suggest this circuit is running with
no or reversed evaporator water flow.
Remote
Evaporator Water
Flow (High Approach
Temperature)-
Circuit 2
Chiller
Immediate
Shutdown
Latching
Ckt Energized
[Ckt Not
Energized]
Large evaporator approach temps, low evap sat temps, and
presence of liquid refrigerant, suggest this circuit is running with
no or reversed evaporator water flow.
Remote
Evaporator Water
Flow Lost
Chiller Immediate NonLatch
Whenever Evap
Pump is
commanded on
due to Auto mode
and certain off-
cycle diagnostics
a. The Evaporator water flow switch input was open for more
than 6-10 sec (HV binary input) or 20-25* sec (for factory mtd
low voltage binary input) b. This diagnostic does not de-
energize the evap pump output c. 6-10 seconds of contiguous
flow shall clear this diagnostic. d. Even though the pump times
out in the STOP modes, this diagnostic shall not be called out in
the STOP modes, (with the exception of pump override due to
certain off-cycle diagnostics). * could be longer if water temps
are rapidly changing warmer
Remote
Evaporator Water
Flow Overdue
Chiller Normal NonLatch
Whenever Evap
Pump is
commanded on
due to Auto mode
and certain off-
cycle diagnostics
Evaporator water flow was not proven within 4:15 (RTAC Rev 20
and earlier) or 20:00 (RTAC Rev 21) of the Evaporator water
pump relay being energized. With SW Rev 17.0 and earlier, the
diagnostic will de-energize the Evaporator Water Pump output.
It will be re-energized if the diagnostic clears with the return of
flow and the chiller will be allowed to restart normally (to
accommodate external control of pump) With SW Rev 18.0 and
later, the pump command status will not be effected. In the case
of certain "Off-cycle" diagnostics in which the pump is
overridden to on, the delay to callout of the diagnostic is
shortened to 4:15.
Remote
External Chilled
Water Setpoint
None Info NonLatch All
a. Function Not "Enabled": no diagnostics. b. "Enabled ": Out-
Of-Range Low or Hi or bad LLID, set diagnostic, default CWS to
next level of priority (e.g. Front Panel SetPoint). This Info
diagnostic will automatically reset if the input returns to the
normal range.
Remote
External Current
Limit Setpoint
None Info NonLatch All
a. Not "Enabled": no diagnostics. b. "Enabled ": Out-Of-Range
Low or Hi or bad LLID, set diagnostic, default CLS to next level
of priority (e.g. Front Panel SetPoint. This Info diagnostic will
automatically reset if the input returns to the normal range.
Remote
High Differential
Refrigerant Pressure
- Circuit 1
Circuit Normal Latch Cprsr Energized
The system differential pressure for the respective circuit was
above 275 Psid for 2 consecutive samples or more than 10
seconds.
Remote
Table 67. Main processor diagnostics (continued)
Diagnostic Name
Affects
Target Severity
Persist-
ence
Active Modes
[Inactive
Modes] Criteria
Reset
Level
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