Manitowoc Ice QC0700, QF2300, QF0800 Section, Refrigeration System, Before Beginning Service

Section 7 Refrigeration System

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/QUALITY CHECK

Quality Check

Ice quality will vary with ambient and water temperatures, and is measured by the amount of excess water in the ice. An easy test is to squeeze a handful of ice. High quality ice releases only a small amount of water. As ice quality drops, more water can be removed.

Generally speaking, higher incoming water temperature results in lower ice quality.

Lower water temperature results in higher ice quality.

Ice Production Check

1.Run the ice machine a minimum of 10 minutes to allow the system to stabilize.

2.Catch the ice in a non-perforated container for

7 minutes and 12 seconds or for more accuracy

14 minutes and 24 seconds.

3.Weigh the container and ice, then deduct the weight of the container.

4.Convert ounces to pounds.

Example: 3 lbs. 12 oz. converts to 3.75 lbs.

(12 oz. ÷ 16 oz. =.75 lb.)

5.Determine the 24-hour ice production capacity.

7 minutes 12 seconds

Multiply the total ice weight by 200.

14 minutes 24 seconds

Multiply the total ice weight by 100. Example:

Collected ice for 7 minutes 12 seconds Total weight (minus container) = 3.75 lbs.

3.75 lbs. x 200 = 750 lbs. of ice every 24 hours

6.Compare the capacity to the 24-hour ice production chart for the model being tested.

Ice production checks that are within 10% of the charted capacity are considered normal due to variances in air and water temperatures. Actual temperatures will seldom match the chart exactly.

Part No. 80-1214-3 Revised 8/2003 7-5