Operating instructions
12
9
10
11
14
13
12
7
1
2
3
4
5
6
32
15
29
28
27
26
25
22
30
31
18
19
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21
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24
16
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8
33
1. Guide vane actuator
2. Suction elbow
3. Compressor
4. Cooler valve*
5. Cooler pressure transducer
6. Condenser in/out temperature thermistors
7. Cooler in/out temperature thermistors
8. Machine identication nameplate (situated on the starter cabinet side) - see
right-hand gure 'Rear view'
9. Refrigerant charging valve
10. Typical ange connections
11. Oil drain valve
12. Oil level sight glass
13. Refrigerant oil cooler (hidden)
14. Branch circuit control box
* One relief valve is standard. The optional dual relief valves include
change-over for each heat exchanger.
15. Condenser auto reset relief valves*
16. Circuit breaker/disconnect switch
17. ICVC
18. Unit-mounted starter (19XR) or variable-frequency drive (19XRV)
19. Motor sight glass
20. Cooler return-end waterbox cover
21. Cooler nameplate
22. Condenser nameplate
23. Typical waterbox drain port
24. Condenser return-end waterbox cover
25. Refrigerant moisture/ow indicator
26. Refrigerant lter/drier
27. Liquid line isolation valve (optional)
28. Linear oat valve chamber
29. Vessel take-apart connector
30. Discharge isolation valve (optional)
31. Pumpout valve
32. Condenser pressure transducer
2.3.3 - Refrigeration cycle
The compressor continuously draws refrigerant vapour
from the cooler at a rate set by the amount of guide vane
opening. As the compressor suction reduces the pressure in
the cooler, the remaining refrigerant evaporates at a fairly
low temperature (typically 3 to 6°C). The energy required
for evaporation is obtained from the water flowing through
the cooler tubes. With heat energy removed, the water
becomes cold enough for use in an air conditioning circuit or
process liquid cooling, light industrial or marine applications.
After taking heat from the water, the refrigerant vapour is
accelerated in a turbine. This increases its pressure by
increasing the speed. Compression adds still more heat
energy, and the refrigerant is quite warm (typically 37 to
40°C) when it is discharged from the compressor into the
condenser.
Relatively cool (typically 18 to 32°C) water flowing into
the condenser tubes removes heat from the refrigerant and
the vapour condenses to liquid.
The liquid refrigerant passes through orifices into the FLASC
(Flash Subcooler) chamber (see Fig. 3 - “Typical 19XR unit
diagram”).
Since the FLASC chamber is at a lower pressure, part of
the liquid refrigerant flashes to vapour, thereby cooling the
remaining liquid.
The FLASC vapour is recondensed on the tubes which are
cooled by entering condenser water. The liquid drains into
a float chamber between the FLASC chamber and cooler.
Here a float valve forms a liquid seal to keep FLASC
chamber vapour from entering the cooler.
When liquid refrigerant passes through the valve, some of
it flashes to vapour in the reduced pressure on the cooler
side. In flashing, it removes heat from the remaining liquid.
The refrigerant is now at a temperature and pressure at
which the cycle began.
NOTE: In the 19XRV units a modification has been
introduced in the refrigerant circuit to ensure cooling of
the variable-frequency drive that supplies the compressor.
For 19XRV particulars refer to chapters 8 to 14.
Non-certied drawings. Refer to the certied dimensional drawings supplied with the unit or available on request, when designing an installation.