OPERATING AND MAINTENANCE MANUAL
Chapter 8 - Other components
iC 215 ÷ iC 780
56
The data in this manual are not binding and they can be modified by the manufacturer without notice.
Reproduction of this manual is strictly prohibited
ENGLISH
EN
C
HAPTER
8
O
T H E R C O M P O N E N T S
8 . 1
C o m p r e s s o r m o t o r p r o t e c t i o n
The unit is equipped with an internal motor protection system by means of a power circuit breaker.
8 . 2
R e f r i g e r a n t h i g h a n d l o w p r e s s u r e s w i t c h e s
The units are equipped with the following pressure switches:
1.
low pressure switch (LP)
This monitors refrigerant compressor suction pressure and will trip to protect the compressor if the pressure falls
to potentially hazardous values that could harm the compressor. The pressure switch is of the “automatic reset”
type. Alarm
b1LP
or
b2LP
(see chapter “7.11.8 Low pressure switch alarm”), generated by tripping of this
pressure switch, can be delayed with respect to start-up of the compressor, to prevent temporary fluctuations in
suction pressure or false alarms from interfering with correct operation of the unit. Once the preset time interval
has elapsed tripping of this pressure switch will be detected by the electronic control unit, which will display
alarm signal
b1LP
or
b2LP
(see chapter “7.11.8 Low pressure switch alarm”) and shut down the compressor(s),
while the pump (if installed) will continue to run. After the alarm has tripped if the compressor suction pressure
increases and exceeds the reset value the pressure switch will reset. The unit can be restarted by following the
alarms reset procedure described in Chapter 7 “Electronic controller”. If the cause of the pressure switch trip has
not been remedied this cycle will be repeated continuously.
2.
high pressure switch (HP)
This monitors the refrigerant compressor discharge pressure and prevents it increasing to potentially hazardous
values that could harm the compressor and people within the vicinity. The pressure switch is of the “automatic
reset” type. Tripping of this pressure switch is read by the electronic controller, which opens the compressor
power feeding circuit and displays alarm signal
b1HP
or
b2HP
(see section “7.11.8 Low pressure switch alarm”).
When the compressor discharge pressure decreases and falls below the reset point, the pressure switch resets
automatically.
The unit can then be restarted according to the alarm reset procedure described in Chapter 7 “Electronic
controller”.
If the cause of pressure switch activation is not eliminated, this cycle may be repeated continuously.
The LP and HP pressure switches are connected to the refrigerant circuit pipes by means of SCHRAEDER valves (with
needle) that prevent the refrigerant from escaping if the pressure switches are to be replaced.
The TRIP and RESET values of the pressure switches depend on the type of refrigerant and are shown in the following table:
8 . 3
F a n p r e s s u r e s w i t c h e s ( M o d e l s i C 2 1 5 ÷ 5 4 0 )
With fan speed control in ON/OFF mode these units are equipped with a Pressure switch (
FP
) that monitors the refrigerant
compressor discharge pressure and is responsible for controlling operation of the fans in ON-OFF mode, i.e. connecting or
disconnecting the fans electrical power supply.
The FP pressure switch is connected to the refrigerant circuit pipes by means of SCHRAEDER valves (with needle) that
prevent refrigerant from escaping if the pressure switch is to be replaced.
The TRIP and RESET values of the pressure switch depend on the type of refrigerant and are shown in the following table:
Pressure switch
Refrigerant
gases
TRIP
RESET
bar
°C
bar
°C
HP
R410A
41
64.7
33
55.0
LP
2.5
-23.8
4
-14
Pressure switch
Refrigerant
gases
TRIP
RESET
bar
°C
bar
°C
Axial Fans
FP
R410A
27
46.1
21
36.1