Diagnostics
RTHD-SVX02H-EN 115
Table 35. Diagnostics Table
Hex
Code
Diagnostic Name
and Source
Severity Persistence Criteria Reset
Level
59D Loss of Oil at Com-
pressor (Stopped)
Immediate
and Special
Action
Latch Oil Loss Level Sensor detects a lack of oil in the oil tank feeding
the compressor for 90 seconds after EXV preposition is complet-
ed. Note: Compressor start is delayed while waiting for oil to be
detected.
Local
C5 Low Chilled Water
Temp: Unit Off
Info and Spe-
cial Action
NonLatch The leaving chilled 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 Evap Water pump Relay until diagnostic auto resets,
then return to normal evap pump control. Automatic reset occurs
when the temp rises 2°F (1.1°C) above the cutout setting for 30
minutes.
Remote
C6 Low Chilled Water
Temp: Unit On
Immediate
and Special
Action
NonLatch The chilled water temp. fell below the cutout setpoint for 30
degree F Seconds while the compressor was running. Automatic
reset occurs when 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
1AE Low Differential Re-
frigerant Pressure
Immediate Latch The system differential pressure was either below 15 Psid for
more than 164 Psid-sec, or below 23.0 Psid for 3000 Psid-sec.
The latter integral’s value is not cleared for any reason including
diagnostic trip, manual reset, or power up reset (ie. Integral is
saved nonvolatily on power down). The integral will decay while
circuit is running at a max rate of -10 PSID, and while stopped at
a rate of -0.4 PSID. This same integral is associated with the op-
erating mode “Compressor Cool Down”. Also see diagnostic below
Remote
18E Low Discharge Su-
perheat
Normal Latch While Running Normally, the Discharge Superheat was less than
12 degrees F +- 1F for more than 6500 degree F seconds.. At
startup the UCM shall ignore the Discharge Superheat for 5.
Remote
583 Low Evaporator Liq-
uid Level
Info NonLatch The liquid level sensor is seen to be at or near its low end of
range for 80 contiguous minutes while the compressor is running.
Design: 20% or less of bit count corresponding to -21.2 mm or
less liquid level for 80 minutes)
Remote
B5 Low Evaporator Re-
frigerant Pressure
Immediate Latch The Evaporator Refrigerant Pressure dropped below 10 psia just
prior to compressor start. The pressure fell below 10 psia while
running but before the 1 minute ignore time had expired or fell
below 16 Psia after the 1 minute ignore time had expired.
Local
FB Low Evaporator
Refrigerant Tempera-
ture
Immediate Latch a. The inferred Saturated Evap Refrigerant Temperature (calculat-
ed from suction pressure transducer( s)) dropped below the Low
Refrigerant Temperature Cutout Setpoint for 450°F-sec (10°F-sec
max rate) while the circuit was running after the ignore period
had expired. The integral is held at zero for the 1 minute ignore
time following the circuit startup and the integral will be limited
to never trip in less than 45 seconds, i.e. the error term shall be
clamped to 10°F. The minimum LRTC setpoint is -5°F (18.7 Psia)
the point at which oil separates from the refrigerant. b. During
the timeout of the trip integral, the unload solenoid(s) of the run-
ning compressors on the circuit, shall be energized continuously
and the load solenoid shall be off. Normal load/unload operation
will be resumed if the trip integral is reset by return to temps
above the cutout setpoint.
Remote
6B3 Low Evaporator
Temp: Unit Off
Info and Spe-
cial Action
NonLatch The evap sat temp fell below the water temp cutout setting while
the respective evap liquid level was greater than -21.2mm for
30 degree F seconds while Chiller is in the Stop mode, or in Auto
mode with no compressors running. Energize Evap Water pump
Relay until diagnostic auto resets, then return to normal evap
pump control. Automatic reset occurs when either the evap temp
rises 2°F (1.1°C) above the cutout setting or the liquid level falls
below - 21.2mm for 30 minutes
Remote
198 Low Oil Flow Immediate Latch The oil pressure was out of the acceptable pressure range for 15
seconds, while the Delta Pressure was greater than 23.8 Psid.:
Acceptable range is 0.50 > (PC-Po) / (PC-PE) for the rst 2.5
minutes of operation, and 0.40 > (PC-Po) / (PC-PE) thereafter,
Local
E2 Momentary Power
Loss
Immediate Nonlatch Momentary Power Loss option disabled: No effect. Momentary
Power Loss option enabled: A loss of power on three line cycles
or more was detected. Diagnostic is reset in 30 seconds. See
Momentary Power Loss Protection specication for additional
information.
Remote
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