ESIE07-05
Functional Control
Part 2 – Functional Description
2–69
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2
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5
1
2.16
High Pressure Setback
Introduction
This is a safety prevention function, when high pressure is near to the high pressure switch setpoint.
The unit will hold same capacity or will load-down to prevent the unit from tripping on the high pressure
switch or transducer high pressure alarm.
Function
description
■
Hold capacity area: if the HP is above the “P hold cond” setpoint (default 17.5 bar) the compressor
will hold the same capacity (no load-up possible)
■
Load down area: if the HP is above the “P down cond” setpoint (default 18.5 bar) the compressor
will load down in order to decrease the high pressure
■
Above HP switch: the unit will shutdown safely
P Hold Cond.
17.5 b
HP Switch
21.5 b
P Down Cond.
18.5 b
HP (bar)
Time
unit switched off by
HP switch
load down area
hold capacity area
ESIE07-05.book Page 69 Friday, December 21, 2007 3:21 PM
