QF400 SELF-CONTAINED AIR COOLED

Section 7

Refrigeration System

 

 

Cycle Time/24 Hour Ice Production/Refrigerant Pressure Charts

These charts are used as guidelines to verify correct ice machine operation. Accurate collection of data is essential to obtain the correct diagnosis.

Refer to “Refrigeration System Diagnostics” for the data that must be collected. This list includes: before beginning service, ice production check, installation/ visual inspection, water system checklist, ice formation pattern, safety limits, safeguards and suction pressure analysis.

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

Zero out manifold gauge set before obtaining pressure readings to avoid misdiagnosis.

Discharge and suction pressure are highest at the beginning of the cycle. Suction pressure will drop throughout the cycle. Verify the pressures are within the range indicated.

All pressure readings must be obtained at the ice machine head section. Lineset length will affect pressures at the condensing unit.

QF400 SELF-CONTAINED AIR COOLED

NOTE: These characteristics may vary depending on operating conditions.

24 Hour Ice Production

Air Temp.

Water Temperature °F/°C

Entering

 

 

 

 

 

 

Condenser

50/10.0

70/21.1

90/32.2

°F/°C

 

 

 

 

 

 

 

70/ 21.1

395

360

335

 

 

 

 

80/26.7

375

320

300

 

 

 

 

90/32.2

335

300

270

 

 

 

 

100/37.8

295

250

240

 

 

 

 

110/43.3

255

230

225

 

 

 

 

Operating Pressures

Air Temp. Entering

Freeze Cycle

 

 

Discharge

Suction

Condenser °F/°C

Pressure PSIG

Pressure PSIG

 

 

 

 

50/10.0

160-180

27-29

 

 

 

70/21.1

210-235

32-35

 

 

 

80/26.7

250-295

34-39

 

 

 

90/32.2

285-315

37-41

 

 

 

100/37.8

320-360

40-46

 

 

 

110/43.3

370-405

44-49

 

 

 

Part No. 80-1214-3

Revised 8/2003

7-11

 

 

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Manitowoc Ice QF0400, QF2300 Section, Refrigeration System, 7-11, QF400 SELF-CONTAINEDAIR COOLED, Hour Ice Production