GEA Grasso - Page 59

Grasso
Refri
g
eration Division
GRASSO SYSTEM CONTROL
01.2004/1 638660E_chapter2.doc Chap. 2 - 23
2.7.2.11 High intermediate pressure alarm
The intermediate pressure is monitored. In case the pressure becomes too high, an alarm is generated. The
alarm does not become active until the start up process has been completed and the additional delay time of 5
minutes has expired. During this time the intermediate pressure is allowed to exceed its maximum limit.
The high intermediate pressure alarm function is illustrated in the following diagram.
P
int
Intermediate pressure
A.. Time characteristic of the
intermediate pressure
W.. Warning limit
Al.. Alarm limit
ML W.. Warning active
ML A.. Alarm active
3.. Reset of the active alarm
Figure 2.27, High intermediate pressure alarm
Interm press 
Pint hi alm n1 
Pint hi alm n2 
Interm press: Actual intermediate pressure in bar (a)
Pint hi alm n1: Alarm limit for maximum intermediate pressure in bar (a)
for low motor speed
Limit values 01 >> Pint hi alm n2: Alarm limit for maximum intermediate pressure in bar (a)
for high motor speed
Interm press 
Pint hi alarm 
High warning - 
Interm press: Actual intermediate pressure in bar (a)
Pint hi alarm: Actual alarm limit for high intermediate pressure in bar (a)
— motor speed dependent!
Limit values 01 >> High warning: Enter the warning value as an offset to the alarm limit in
bar
) Selection of the wrong type of intermediate cool system (ECO system) in the configuration menu can
lead to a too high intermediate pressure. For more information see chapter 2.7.3 ’Two stage
compressor with economiser’.