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Welcome to the Ice-O-Matic ® on-line training modules. Diagnosing Slow Production. This module will cover the possible causes of slow production issues on the ICE Series™ Undercounter, 22” and 30” wide modular units.
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Diagnosing Slow Production This module will cover the possible causes of slow production issues on the ICE Series™ Undercounter, 22” and 30” wide modular units. This module defines slow production as making less than 90% of rated capacity.
Installation Ambient Operating Temperatureat Condenser Self-Contained Need 6 inches Minimum on inlet and outlet of Self Contained Units Minimum : -20° F (-29° C) Maximum : 120° F (49° C) Remote Minimum: 50° F (10° C) Maximum: 110° F (43° C) One of the causes of low production is improper installation location. IOM Cubers are not to be installed outside or in a location that can exceed designed limits.
Installation Incoming Water Supply Water Pressure Minimum : 40° F (4.5° C) Maximum : 100° F (38° C) Water Temperature Minimum: 20 PSIG Maximum: 60 PSIG Excessive water temperature can also cause a unit to produce ice slower than designed. It is a myth that hot water freezes faster than cold.
30” Modular Units The major cause of under production is lack of maintenance. A dirty system will cause less than expected ice production. Always verify the cleanliness of the ice maker prior to making adjustments. An indication of a dirty Evaporator is a normal freeze time, but an extended defrost. Mineral accumulation on the plate can make it difficult for the Harvest Assist Assembly to clear the slab from the plate.
ICE0400HA4 – 70/50 20 Minute cycle time 1440 minutes in a day 1440 divided by 20 = 72 cycles/day Batch weight of 5.5# 72 times 5.5 = 396 # per day. ICE0400HA4 – 90/70 23 Minute cycle time 1440 minutes in a day 1440 divided by 23 = 62.6 cycles/day Batch weight of 5.5# 62.6 times 5.5 = 344 # per day. 1440 divided by Cycle Time times Batch Weight = Production To verify actual production, use this simple formula. Time a cycle from drop to drop. Catch and weigh an ice slab, then do the math as shown above. This example uses ICE0400 Air Cooled units in two different install locations. The one on the left is in a 70 degree room and being fed 50 degree water, the one on the right is in a 90 degree room and being fed 70 degree water. Production charts can be found on each units spec sheets. Which unit is under producing?
ICE0400HA4 – 70/50 20 Minute cycle time 1440 minutes in a day 1440 divided by 20 = 72 cycles/day Batch weight of 5.5# 72 times 5.5 = 396 # per day. ICE0400HA4 – 90/70 23 Minute cycle time 1440 minutes in a day 1440 divided by 23 = 62.6 cycles/day Batch weight of 5.5# 62.6 times 5.5 = 344 # per day. The unit on the left is rated for approximately 500 pounds of production while the one on the right is rated for 368 pounds in their given locations. It is the one on the left that is under producing. This unit would need to be checked for cleanliness first, then diagnosed for possible issues. It is imperative that the units be cleaned AT LEAST every six months for proper operation.
Water Leaking from Purge Valve Another possible cause of slow production is a leaking Purge Valve. During the freeze cycle, no water should be leaving the unit through the valve. Any water leaking out will be replaced by the float, keeping the water temperature in the trough up and therefore extending the freeze cycle. A visual sign of this would be little to no ice on the top rows of the Evaporator. A leaking Purge Valve should be replaced.
Compressor inefficiency can also cause prolonged production times. The more inefficient the Compressor becomes, the more likely it is to lead to a freeze-up. Compressor RLA should be within 10% of the rating on the data tag 5 minutes into the freeze cycle.
Miss-feeding Thermostatic Expansion Valves can also cause slow production if they do not meter down properly.
Should the Hot Gas Valve be slightly leaking by, this too could cause extended cycle times by keeping the suction pressure elevated, slowing production. There should always be a marked temperature difference between the inlet and outlet of the Hot Gas Valve.