Operation manual
3
EWAD120~340MBYNN
Packaged air-cooled water chillers
4PW22683-1
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 refri-
gerant 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 the water out of the system.
■
Expansion valve
The liquid refrigerant coming from the condenser enters the
evaporator via an expansion valve. The expansion valve brings
the liquid refrigerant to a pressure at which it can easily be
evaporated in the evaporator.
■
Evaporator
The main function of the evaporator is to take heat from the
water that flows through it. This is done by turning the liquid
refrigerant, coming from the condenser, into gaseous
refrigerant.
■
Water in/outlet connection
The water inlet and outlet connection allow an easy connection
of the unit to the water circuit of the air handling unit or industrial
equipment.
■
Flowswitch
The flowswitch protects the evaporator of the unit against
freezing when there is no waterflow or when the waterflow is too
low.
Safety devices
The unit is equipped with three 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
Circuit safety devices
Circuit safety devices shut down the circuit they protect, while
the other circuits remain activated.
3
Part safety devices
Part safety devices shut down the part they protect.
An overview of all safety devices is given below.
■
Overcurrent relay (circuit safety devices)
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 (circuit safety devices)
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.
Y14S
Y15S
B1P
B2P
M1C
R3T
R5T
Y11S
R4T
S14PH
S1PH
Y24S
Y25S
B5P
S4T
M2C
Y21S
S15PH
S2PH
1
2
3
4
5
8
12
9
14
13
10
11
B4P
S3T
6
6
(*)
(*)
A
7
B
7
EWAD240~340
EWAD120~170
S3T
EW
AD120~170
EW
AD240~340
1
Water outlet
7
Safety valve
13
Flowswitch
2
Evaporator
8
Strainer
14
Condenser
3
Water inlet
9
Drier/charge valve
A
Standard
4
Compressor
10
Liquid stop valve
B
Dual pressure relief valve
5
Suction stop valve (optional)
11
Sightglass
(*)
Standard (see A) or optional dual
pressure relief valve (see B)
6
Discharge stopvalve
12
Expansion valve
