Service manual

Section 7 Refrigeration System
Part No. 80-1100-3 7-11
ICE FORMATION PATTERN
Evaporator ice formation pattern analysis is helpful in ice
machine diagnostics.
Analyzing the ice formation pattern alone cannot
diagnose an ice machine malfunction. However, when
this analysis is used along with Manitowoc’s
Refrigeration System Operational Analysis Table, it can
help diagnose an ice machine malfunction.
Improper ice formation can be caused by any number of
problems.
Example: An ice formation that is “extremely thin on top”
could be caused by a hot water supply, a dump valve
leaking water, a faulty water fill valve, a low refrigerant
charge, etc.
1. Normal Ice Formation
Ice forms across the entire evaporator surface.
At the beginning of the freeze cycle, it may appear that
more ice is forming on the bottom of the evaporator than
on the top. At the end of the freeze cycle, ice formation
on the top will be close to, or just a bit thinner than, ice
formation on the bottom. The dimples in the cubes at the
top of the evaporator may be more pronounced than
those on the bottom. This is normal.
The ice thickness probe must be set to maintain the ice
bridge thickness at approximately 1/8". If ice forms
uniformly across the evaporator surface, but does not
reach 1/8" in the proper amount of time, this is still
considered normal.
2. Extremely Thin at Evaporator Outlet
There is no ice, or a considerable lack of ice formation
on the top of the evaporator (tubing outlet).
Examples: No ice at all on the top of the evaporator, but
ice forms on the bottom half of the evaporator. Or, the ice
at the top of the evaporator reaches 1/8" to initiate a
harvest, but the bottom of the evaporator already has
1/2" to 1" of ice formation.
Figure 7-8. Extremely Thin Ice Formation at
Evaporator Outlet
Important
Keep the water curtain in place while checking the
ice formation pattern to ensure no water is lost.
SV1576
OUTLET
INLET
ICE
ICE