Vogt Tube-Ice HFO10, Service Manual

Page: 71 / 112

8-3
Freeze-Up from Ice Failing to Discharge
Possible Causes Possible Solutions
Insufficient heat for thawing
because of low condensing
pressure, non-condensable gases
(usually air) in system, low
refrigerant charge, or thaw gas
pressure switch adjusted too low The head pressure should be maintained at approximately 130 psig (9
bar) for 513A, which relates to 98.7°F (37.0°C) by adjusting the water
regulating valve (water-cooled units) or fan cycling switch (air-cooled
units). If non-condensable gases are present in the refrigerant, the
saturated temperature will not relate to the pressure reading at the
receiver. The refrigerant level in the receiver should be near the
operating level (marked by the sticker) at the end of a freezing period to
provide enough volume for harvesting. (1-in. [2.54 cm] = approx. 10 lb.
[4.5 kg] of 513A).
Thawing time too short Check the thaw timer (T) which should be adjusted to allow all the ice to
clear the cutter and ice discharge opening with at least 30 seconds to
spare.
Cutter or cutter disc does not
turn Check cutter reducer and drive gear for proper operation and alignment.
Check for broken cutter disc or drive pin and replace as necessary.
Ice backs up into cutter or
discharge opening, jamming
cutter Ice mushy due to concentration of solids in the water tank. Perform
"Cleaning Procedure
” and check automatic and adjustable blowdown. If
the machine discharges ice into a chute, it should slope at an angle of
30 degrees for cylinder ice, and 45 degrees for crushed ice. Check bin
stat or level control to make sure it will stop the machine before ice
backs up into the cutter.
Extended freeze period Check freezer pressure switch adjustment, refer to Section 9, (Freezer
Pressure Switch) and Table 21 Normal Operating Criteria.
Compressor not unloading Check compressor amps during harvest. A noticeable drop in amperage
should occur. Check unloader solenoid coil. If coil is okay, replace
unloader head assembly.
Thawing time too short Check the thaw timer (T), which should be adjusted to allow all the ice to
clear the cutter and ice discharge opening with at least 30 seconds to
spare.