ICE MACHINES Q-Model Service Manual

Section 7Refrigeration System10. Follow the normal evacuation procedure, exceptreplace the evacuation step with the following:ImportantDry nitrogen is recommended for this procedure.This will prevent CFC release.A. Pull vacuum to 1000 microns. Break the vacuumwith dry nitrogen and sweep the system.Pressurize to a minimum of 5 psi.B. Change the vacuum pump oil.C. Pull vacuum to 500 microns. Break the vacuumwith dry nitrogen and sweep the system.Pressurize to a minimum of 5 psi.D. Change the vacuum pump oil.E. Pull vacuum to 250 microns. Run the vacuumpump for 1/2 hour on self-contained models, 1hour on remotes.NOTE: You may perform a standing vacuum test tomake a preliminary leak check. You should use anelectronic leak detector after system charging to be surethere is no leak.11. Charge the system with the proper refrigerant to thenameplate charge.12. Operate the ice machine for one hour. Then, checkthe pressure drop across the suction line filter-drier.A. If the pressure drop is less than 1 psi, the filterdriershould be adequate for complete cleanup.B. If the pressure drop exceeds 1 psi, change thesuction line filter-drier and the liquid line drier.Repeat until the pressure drop is acceptable.13. Operate the ice machine for 48-72 hours. Then,remove the suction line drier and change the liquidline drier.14. Follow normal evacuation procedures.REPLACING PRESSURE CONTROLS WITHOUTREMOVING REFRIGERANT CHARGEThis procedure reduces repair time and cost. Use itwhen any of the following components requirereplacement, and the refrigeration system is operationaland leak-free.• Fan cycle control (air-cooled only)• Water regulating valve (water-cooled only)• High pressure cut-out control• High side service valve• Low side service valveImportantThis is a required in-warranty repair procedure.1. Disconnect power to the ice machine.2. Follow all manufacturer’s instructions supplied withthe pinch-off tool. Position the pinch-off tool aroundthe tubing as far from the pressure control asfeasible. (See the figure on next page.) Clamp downon the tubing until the pinch-off is complete.! WarningDo not unsolder a defective component. Cut it out ofthe system. Do not remove the pinch-off tool untilthe new component is securely in place.3. Cut the tubing of the defective component with asmall tubing cutter.4. Solder the replacement component in place. Allowthe solder joint to cool.5. Remove the pinch-off tool.6. Re-round the tubing. Position the flattened tubing inthe proper hole in the pinch off tool. Tighten thewingnuts until the block is tight and the tubing isrounded. (See the drawing on next page.)NOTE: The pressure controls will operate normally oncethe tubing is re-rounded. Tubing may not re-round100%.Part No. 80-1100-3 7-55