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D-EOMCP00104-14_01EN
6
ALARMS AND TROUBLESHOOTING
6.1 Unit trips
Unit trips are caused by:
•
Low evaporator flow rate. A "Low evaporator flow rate alarm" will trip the whole unit if the evaporator flow switch
remains open for more than an adjustable value; the alarm are automatically reset for three times if the evaporator
flow switch closes for more than 30 seconds. Starting from the fourth alarm it has to be reset manually.
•
Low evaporator outlet temperature. A "Low evaporator outlet temperature alarm" will trip the whole unit as soon as the
evaporator leaving water temperature falls below the freeze alarm setpoint. A manual reset of the alarm are required
to restart the unit
•
Phase-Voltage Monitor (PVM) or Ground Protection (GPF) failure.A "Bad phase/voltage or Ground protection failure
alarm" will trip the whole unit as soon as the phase monitor switch opens (if a single phase monitor is used) after the
unit start request.A manual reset of the alarm will required to restart the unit
•
Evaporator leaving water temperature fault.An "Evaporator leaving water temperature fault alarm" will trip the whole
unit if the reading of evaporator leaving water temperature goes out of probe allowable range for a time longer than
ten seconds.A manual reset of the alarm will required to restart the unit.
•
External alarm (only if enabled).A "External alarm" will trip the whole unit as soon as the external alarm switch closes
after the unit start request, if the unit trip on external alarm has been set. A manual reset of the alarm will required to
restart the unit.
•
Probe failure.A "Probe failure" will trip the unit if the reading of one among the following probes goes out of probe
allowable range for a time longer than ten seconds.
-
Evaporator #1 leaving temperature probe (on 2 evaporators units)
-
Evaporator #2 leaving temperature probe (on 2 evaporators units)
The controller display will show the faulted probe identification
6.2 Compressors trip
Compressor trips are caused by:
•
Mechanical High pressure.A "High pressure switch alarm" will trip the compressor as soon as the high pressure switch
opens.A manual reset of the alarm is required to restart the unit (after the manual reset of the pressure switch).
•
High discharge pressure. A "High discharge pressure alarm" will trip the compressor as soon as the compressor
discharge pressure exceeds the adjustable high pressure setpoint.A manual reset of the alarm are required to restart
the unit
•
High discharge temperature. A "High discharge temperature alarm" will trip the compressor as soon as the compressor
discharge temperature exceeds the adjustable high temperature setpoint.A manual reset of the alarm are required to
restart the unit.
•
Low evaporator outlet temperature. A "Low evaporator outlet temperature alarm" will trip the compressors as soon as
the evaporator leaving water temperature falls below the adjustable freeze threshold. A manual reset of the alarm are
required to restart the unit
•
Mechanical Low pressure. A "Low pressure switch alarm" will trip the compressor if the low pressure switch opens for
more than 40 seconds during compressor running. Five automatic reset alarms (both from transducers and switches)
are managed in all modes (cooling, cooling glycol, ice, heat pump). These alarms switch off the compressor without
signalling (alarm relay is not activated). Only the sixth will be a manual reset alarm.The "Low pressure switch alarm"
are disabled during prepurge cycles and during pumpdown. At compressor startup (after the end of prepurge cycles)
the "Low pressure switch alarm" is disabled if a low ambient start has been recognized otherwise are delayed by 120
sec.A manual reset of the alarm are required to restart the unit
•
Low suction pressure.A "Low suction pressure alarm" will trip the compressor if the compressor suction pressure
remains below the adjustable low pressure alarm setpoint for a time longer than that listed in the following table. Low
suction pressure alarm delay
Low press setpoint – Suct press
(bar / psi)
0.1 / 1.45
0.3 / 4.35
0.5 / 7.25
0.7 / 10.15
0.9 / 13.05
1.0 / 14.5
32/35
Alarm delay
(seconds)
160
140
100
80
40
0
Operating Manual
EWYD_BZ
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