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: 14.8 - 15.9 minutesPublished freeze cycle suction pressure: 65 - 26 psig2B. Compare the published freeze cycle time andpublished freeze cycle suction pressure. Develop a chart.Example:Published Freeze Cycle Time (minutes)1 2 4 7 10 12 14| | | | | | |65 55 47 39 34 30 26Published Freeze Cycle Suction Pressure (psig)In the example, the proper suction pressure should beapproximately 39 psig at 7 minutes; 30 psig at 12minutes; 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: 79 (at 1 min.)Middle of freeze cycle: 48 (at 7 min.)End of freeze cycle: 40 (at 14 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 65 psig (at 1 minute) – not 79Approximately 39 psig (at 7 minutes) – not 48Approximately 26 psig (at 14 minutes) – not 40118 Part Number 80-01111-9 7/10