Section 7 | Refrigeration System |
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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.
2. Extremely Thin at Evaporator Outlet
There is no ice, or a considerable lack of ice formation at the outlet of the evaporator.
Examples: No ice at all at the outlet half of the evaporator, but ice forms at the inlet half of the evaporator. Or, the ice at the outlet of the evaporator reaches 1/8" to initiate a harvest, but the inlet of the evaporator already has 1/2" to 1" of ice formation.
Possible cause: Water loss, low on refrigerant, starving TXV, faulty water fill valve etc.
Important
Keep the water curtain in place while checking the ice formation pattern to ensure no water is lost.
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 at the inlet of the evaporator than at the outlet. At the end of the freeze cycle, ice formation at the outlet will be close to, or just a bit thinner than, ice formation at the inlet. The dimples in the cubes at the outlet of the evaporator may be more pronounced than those at the inlet. 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.
NO ICE or THIN ICE
OUTLET
ICE
INLET
Figure 7-3. Extremely Thin Ice Formation at
Evaporator Outlet
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