It is possible that the machine needs a really good cleaning. Or, the unit may be undersized for how much it is used and what the temperature around it may be.
When you arrive at the jobsite, first do a quick visual inspection of the unit. Look for signs that normal maintenance has not been performed; this can seriously affect ice production. Remember, regular maintenance really pays big benefits towards better efficiency and maximum production.
Generally, manufacturers recommend a service schedule that includes cleaning the water system with an acid-based ice machine cleaner and sanitizing to eliminate bacteria. Annual cleaning is usually recommended.
However, additional regular service may be required in areas with bad water.
Cleaning instructions are usually located on the cleaning label and/or in the instruction manual that comes with the unit. Be sure to follow the instructions and use the cleaner recommended by the manufacturer; this will protect a plated-type evaporator from damage due to harsh chemicals.
You will need to time a complete cycle, from the beginning of one freeze cycle to the beginning of the next. You will need to catch the ice produced during this cycle and weigh it.
The formula for checking ice production is to divide the cycle time (in minutes) into 1,440 min to get the number of cycles the unit will run in a day. Then multiply the number of cycles by the ice drop weight (in pounds) for the total ice production in 24 hrs.
1,440 Ã· Cycle Time X Ice Drop Weight = Production
While you are waiting for the cycle to complete, check the manufacturer’s data on that specific model number to determine what the production should be. Data charts are generally available to show production, ice drop weight, and approximate cycle times under a variety of conditions.
You will need to know the incoming water temperature and ambient temperature around the unit to cross-reference the data chart.
Once the production test is completed, compare the results with the manufacturer’s data. If the amounts are close, that is likely all of the ice that will be produced by that machine in one day.
If the production is inadequate, seize the opportunity to sell the customer a larger ice machine.
It is possible, however, that the customer may have the appropriate machine production but does not have enough storage to get through heavy-use periods. In this case, there are usually two choices. They can bank ice in bags in the freezer for hot days, or change to a larger storage bin.
If the production is not within the manufacturer’s specifications, it’s time to check the refrigeration cycle.
Most ice machines use a standard thermostatic expansion valve system. These ice machines have a critical charge system for maximum ice production. The refrigerant type and correct charge are usually listed on the unit nameplate.
The key to proper production is proper cycle time. The freeze and harvest times should closely match the manufacturer’s specifications for the air and water temperatures at which you are operating.
Remember that while all ice machines perform the same function, the operational sequence varies between manufacturers. Cycle time also varies. Some manufacturers prefer long cycle times while others prefer short cycle times. Know your products well enough that you can spot a problem if it exists.
Moore is director of technical support for Hoshizaki America Inc., Peachtree City, GA. He can be reached at email@example.com (e-mail).
Publication date: 03/05/2001