ICE MACHINES Q-Model Service Manual

Electrical System Section 6Q-Model Automatic Shut-Off and RestartWhen the storage bin is full at the end of a harvest cycle,the sheet of cubes fails to clear the water curtain and willhold it open. After the water curtain is held open for 7seconds, the ice machine shuts off. To assure the PTCRhas cooled, the ice machine remains off for 3 minutesbefore it can automatically restart.The ice machine remains off until enough ice has beenremoved from the storage bin to allow the ice to fall clearof the water curtain. As the water curtain swings back tooperating position, the bin switch closes and the icemachine restarts, provided the three-minute delay periodis complete.L1SV1506Figure 6-15. During Start-Up (First .25 - 1.0 Seconds)L1CONTACTORCONTACTSCCONTACTORCONTACTSSCOMPRESSORCRRSCOMPRESSORRUN CAPACITORRPTCRRRUN CAPACITORRRL2L2Troubleshooting PTCR’sWHY A GOOD PTCR MAY FAILTO START THE COMPRESSORThe PTCR must be cooled before attempting to start thecompressor, otherwise the high starting torque may notlast long enough.For example, if the PTCR is properly cooled, say 60°F(15.6°C) when the compressor starts, it will take .25 to1.0 seconds before its temperature reaches 260°F(126.6°C), and current flow is stopped.If the PTCR is still warm, say 160°F (71.1°C) when thecompressor starts, it will take only .125 to .50 secondsbefore its temperature reaches 260°F (126.6°C), andcurrent flow is stopped. This decreased time may beinsufficient to start the compressor.A good PTCR may be too hot to operate properly atstart-up because:• The ice machine’s 3-minute delay has beenoverridden. Opening and closing the servicedisconnect or cycling the toggle switch from OFF toICE will override the delay period.• The control box temperature is too high. Thoughrare, very high air temperatures (intense sunlight,etc.) can greatly increase the temperature of thecontrol box and its contents. This may require alonger off time to allow the PTCR to cool.• The compressor has short-cycled, or the compressoroverload has opened. Move the toggle switch to OFFand allow the compressor and PTCR to cool.Continued on next page …PTCRSV1507Figure 6-16. After Start-Up(Current Flows Through Run Capacitor)6-42 Part No. 80-1100-3