Vogt P-24AL, Руководство по обслуживанию

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P24AL & P34AL Service Manual
TROUBLESHOOTING
12/2016
8-5
Symptom: Freeze-up due to ice failing to discharge
Possible Cause Possible Remedy
Freeze timer (1TR) set to long Adjust timer or replace if defective. See Figure
9-2.
Extended freeze period (if 2PS is used) Check freezer pressure switch (2PS)
adjustment. See Figure 9-3 for adjustment and
Table 7-2 for average hole size. Make sure all
water distributors are in place (one in each
tube).
Thaw time too short (2TR) Adjust thaw timer (2TR) to allow all ice to
clear the cutter and ice discharge opening with
at least 30 seconds to spare. Replace defective
timer. See pressure regulating valve adj.
Thaw pressure to low The thaw gas regulator should be adjusted to
increase the pressure in the freezer to 60-65
psig during a harvest. Isolate and repair or
replace the valve as needed.
Insufficient heat for thawing due to low
condensing pressure The head pressure should be maintained form
175-190 psig (maximum 200) usually by a
water regulating valve or fan cycling switch.
Check to make sure these controls are working
properly. Cold prevailing wind can also be a
factor.
Insufficient heat due to non-condensables
(usually air) in the system If non-condensables are present with the
refrigerant, the saturated temperature will not
relate to the pressure reading at the receiver
and the refrigerant will be cooler, although
pressure will be high. Air can be purged from
the system by following the procedure in the
Section 9, “Purging Non-Condensables”.
Insufficient heat due to low refrigerant charge The refrigerant level in the receiver should be
near the operating mark at the end of a freezing
cycle to provide enough volume of warm gas
for harvesting. DO NOT OVERFILL
RECEIVER. See Table 3-2
Cutter or cutter disc does not turn Check cutter gear reducer and drive gear for
proper operation and alignment. Check for
broken gear teeth or sheared shaft key.
Replace defective parts.
Compressor not running unloaded during thaw
cycle. (for dedicated high side only) Check compressor motor Amp draw. During
the thaw cycle, the compressor motor Amp
draw should be 60 - 70% of normal amp draw
during the freeze cycle. Check compressor
unloader solenoid coil (UR) to make sure it is
energized and the valve opening during the
thaw cycle.