Operation manual
3
ERAP110~170MBYNN
Air-cooled condensing units
4PW22681-1
Function of the main components
Figure - Functional diagram
As the refrigerant circulates through the unit, changes in its state or
condition occur. These changes are caused by the following main
components:
■
Compressor
The compressor (M*C) acts as a pump and circulates the
refrigerant in the refrigeration circuit. It compresses the
refrigerant vapour coming from the evaporator at the pressure at
which it can easily be liquefied in the condenser.
■
Condenser
The function of the condenser is to change the state of the
refrigerant from gaseous to liquid. The heat gained by the gas in
the evaporator is discharged through the condenser to the
ambient air, and the vapour condenses to liquid.
■
Filter/drier
The filter installed behind the condenser removes small particles
from the refrigerant to prevent blockage of the tubes.
The drier takes water out of the system.
Safety devices
The unit is equipped with two kinds of safety device:
1
General safety devices
General safety devices shut down all circuits and stop the whole
unit. For this reason the unit has to be manually put on again
after a general safety occurred.
2
Part safety devices
Part safety devices shut down the part they protect.
An overview of all safety devices is given below.
■
Overcurrent relay
The overcurrent relays (K*S) are located in the switchbox of the
unit and protect the compressor motors in case of overload,
phase failure or too low voltage. The relays are factory-set and
may not be adjusted. When activated, they must be reset
manually, followed by a reset of the controller.
■
Compressor thermal protectors
The compressor motors are equipped with thermal protectors
(Q*M). The protectors are activated when the compressor motor
temperature becomes too high.
When temperature returns to normal, the protectors reset
automatically, but the controller needs to be reset manually.
■
Fan motor thermal protector
The condenser fan motors are equipped with thermal protectors
(Q*F). The protectors are activated when the temperature
becomes too high. When temperature returns to normal, the
protectors reset automatically.
■
Discharge thermal protectors
The unit is equipped with discharge thermal protectors (S*T).
The protectors are activated when the temperature of the
refrigerant leaving the compressor becomes too high. When the
temperature returns to normal the protector resets automatically
and the controller needs to be reset manually.
■
Low pressure safety
When the suction pressure of a circuit is too low, the circuit
controller shuts down the circuit. When the pressure returns to
normal, the safety device can be reset on the controller.
■
Pressure relief safety valve
The safety valve is activated when the pressure in the refrigerant
circuit becomes too high. If this occurs, shut down the unit and
contact your local dealer.
Y15S
Y16S
B1P
S3T
M1C
R5T
S14PH
S1PH
Y11S
B2P
M11F
M12F
M14F
M13F
1
4
3
2
5
5
5
B
A
(*)
7
6
1
Condenser
6
Suction stop valve
2
Drier
7
Strainer
3
Charge valve
A
Standard
4
Liquid stop valve
B
Dual pressure relief valve (OP03)
5
Safety valve
(*)
Standard (see A) or dual pressure relief valve (see B)
