Section 7 | Refrigeration System |
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BEFORE BEGINNING SERVICE
Ice machines may experience operational problems only during certain times of the day or night. A machine may function properly while it is being serviced, but malfunctions later. Information provided by the user can help the technician start in the right direction, and may be a determining factor in the final diagnosis.
Ask these questions before beginning service:
•When does the ice machine malfunction? (night, day, all the time, only during the freeze cycle, etc.)
•When do you notice low ice production? (one day a week, every day, on weekends, etc.)
•Can you describe exactly what the ice machine seems to be doing?
•Has anyone been working on the ice machine?
•During “store shutdown,” is the circuit breaker, water supply or air temperature altered?
•Is there any reason why incoming water pressure might rise or drop substantially?
ICE PRODUCTION CHECK
The amount of ice a machine produces directly relates to the operating water and air temperatures. This means an ice machine in a 70°F (21.1°C) room with 50°F (10.0°C) water produces more ice than the same model condensing unit with a 90°F (32.2°C) outdoor ambient temperature and 70°F (21.1°C) water.
1. Determine the ice machine operating conditions:
Air temp. entering condenser: | _______ ° |
Air temp. around ice machine: | _______ ° |
Water temp. entering sump trough: | _______ ° |
2.Refer to the appropriate 24 Hour Ice Production Chart. Use the operating conditions determined in Step 1 to find published 24 hour ice production.
3.Perform an actual ice production check. Use the formula below.
1. | __________ | + | __________ | = | __________ |
Freeze Time |
| Harvest Time |
| Total Cycle Time | |
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2. | 1440 | ÷ | __________ | = | __________ |
Minutes in 24 |
| Total Cycle Time |
| Cycles Per Day | |
| Hours |
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3. | __________ | x | __________ | = | __________ |
Weight of One |
| Cycles Per Day |
| Actual 24 Hour Ice | |
| Harvest |
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| Production |
Important
Times are in minutes.
Example: 1 min., 15 sec. converts to 1.25 min. (15 seconds ÷ 60 seconds = .25 minutes)
Weights are in pounds.
Example: 2 lb., 6 oz. converts to 2.375 lb. (6 oz. ÷ 16 oz. = .375 lb.)
Weighing the ice is the only 100% accurate check. However, if the ice pattern is normal and the 1/8" thickness is maintained, the ice slab weights listed with the 24 Hour Ice Production Charts may be used.
4.Compare the results of step 3 with step 2. Ice production checks that are within 10% of the chart are considered normal. If they match closely, determine if:
•another ice machine is required.
•more storage capacity is required.
•relocating the existing equipment to lower the load conditions is required.
Contact the local Manitowoc distributor for information on available options and accessories.
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