Manitowoc

ProcedureStep1. Determine the ice machine operating conditions.Example:Air temp. entering condenser: 90°F/32.2°CAir temp. around ice machine: 80°F/26.7°CWater temp. entering water fill valve: 70°F/21.1°C2A. Refer to “Cycle Time” and “Operating Pressure” chartsfor ice machine model being checked. Using operatingconditions from Step 1, determine published freeze cycletime and published freeze cycle suction pressure.Example:Published freeze cycle time: 19.1 - 21.7 minutesPublished freeze cycle suction pressure: 20 - 3 psig2B. Compare the published freeze cycle time andpublished freeze cycle suction pressure. Develop a chart.Example:Published Freeze Cycle Time (minutes)1 5 10 15 20| | | | |20 16 12 8 3Published Freeze Cycle Suction Pressure (psig)In the example, the proper suction pressure should beapproximately 16 psig at 5 minutes; 12 psig at 10minutes; etc.3. Perform an actual suction pressure check at thebeginning, middle and end of the freeze cycle. Note thetimes at which the readings are taken.Example:Manifold gauges were connected to the example icemachine and suction pressure readings taken asfollows: ________ psigBeginning of Freeze cycle: 30 (at 1 min.)Middle of freeze cycle: 22 (at 10 min.)End of freeze cycle: 8 (at 20 min.)4. Compare the actual freeze cycle suction pressure (step3) to the published freeze cycle time and pressurecomparison (step 2B). Determine if the suction pressure ishigh, low or acceptable.Example:In this example, the suction pressure is considered highthroughout the freeze cycle. It should have been:Approximately 20 psig (at 1 minute) – not 30Approximately 12 psig (at 10 minutes) – not 22Approximately 3 psig (at 20 minutes) – not 8152 Part Number 80-01111-9 7/10