3.2.5 Application limits
The application limits function monitors if the operating conditions of the compressor is within the safe
operation area limits – as shown in the BITZER Software when doing compressor calculations.
The BITZER Software can be downloaded from BITZER’s homepage, www.bitzer.de.
The operating point is determined by the saturated suction and discharge gas temperatures, which are
calculated from the suction and discharge gas pressure based on the selected refrigerant.
The figure below shows the multi-level monitoring of the application limits and behaviour when a limit is
reached.
Active warning, critical and faults are set inactive when the operating point again is within the reset-limit.
HP cut-out and LP cut-out are configured
in the BEST Software.
Application limit
Warning reset
Warning limit
Critical limit (shut off after 30s)
Fault limit (Immediately shut-off)
High- and Low pressure cut-out
}
Active 120 s after
compressor start
Evaporating temperature t
o
(SST) [°C]
Condensing temperature t
c
(SDT) [°C]
HP cut-out
LP cut-out
Fault limit, direct shut-off:
The compressor will stop immediately if this
limit is reached!
Envelope status = 6 Fault
Critical limit, shut-off after 30 s:
30s delay time to bring compressor back
inside application envelope else the
compressor is stopped with a Fault alarm
Critical (30s period starts)
Envelope status = 5 Critical
Warning limit:
Warning to system controller
No further actions
Envelope status = 4 Warning
Warning reset