Scotsman MAR 106, Руководство по обслуживанию

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Page 19
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Motor Shaft Pulley
MAR units are generally equipped with two
pulleys (not on MAR 126) and by changing
from one to the other the speed of drum can
be changed.
MAR Machines are factory delivered with
pulley to rotate the evaporator drum at the
lowest possible R.P.M. to obtain "THICK"
(2 mm gauge) scale ice. Replacing standard
by alternative/supplied pulley on motor shaft
evaporator drum R.P.M. increases to the point
to produce "THIN" (1 mm gauge) scale ice.
8. Make sure that the automatic expansion valve
opens and that refrigerant fluid starts to flow
through it.
NOTE. At first compressor start-up, the suction
pressure declines rapidly to 0.2 bar, causing
the intervention of the pressure control, which
will interrupt the entire unit operation. This
control being automatic re-set type, will
resume the unit operation after few seconds.
The unit will start and stop few more times,
due to the lo-pressure control cut-out and in,
until system refrigerant pressure set on their
normal values.
9. After two or three minutes of operation, observe
that ice skin begin to form on the revolving
drum surface and it is scraped by the blade.
10.Left the system operate for about 20 minutes.
Check for any excess noise beyond normal
compressor noise.
a) Vibrating type from touching lines.
b) Compressor loose at one or more holddown
bolts.
c) Drivemotor pulley misaligned with gear box
pulley causing V belt vibration.
d) Check compressor oil level through sight
glass (Except MAR 56/76/106/126).
11.On water cooled machine check the water
flowing out from condenser to see if it is
correct. Cooling water flow is controlled by a
pressure water regulating valve. No valve
adjustment of water valve should be
necessary unless the inlet temperature of
cooling water is relatively high. Normal head
pressure should be 17 bar on MAR 56, MAR
76, MAR 106 and MAR 126; 16 bar on MAR
206 and 14 bar on MAR 306.
12.Observe that evaporator drum is frosted all-
over from end to end. If this is not the case
setting of the refrigerant expansion valve
may be necessary. For proper adjustment of
this valve turn the valve setting steam of one
eight of a turn counterckwise to allow more
refrigerant flow until the evaporator drum
surface is evenly frosted from end to end.
In case you have an excessive frost back in
the suction line and frost starts to form on
compressor suction service valve slightly
turn clockwise the expansion valve setting
stem until the frost back on compressor
service valve melts over.
The suction pressure should range
between 0.6 bar and 2.5 bar depending on
model, water temperature and level.
See indications on page 25.
2. WATER AND REFRIGERANT CIRCUIT
1. Compressor
2. Condenser
3. Discharge line
4. Drier
5. Liquid line
6. Heat exchanger
13. Drum water basin
14. Evaporator drum
15. Refrig. lines manifold.
16. Scraping blade
17. Float reservoir
18. Spray bar 7. Expansion valve
8. Vapor line
9. Vibration absorbers
10. Condensing water-inlet
11. Condensing water-outlet
12. Water regulating valve