User manual SCOTSMAN ND750

[. . . ] ND750 INTRODUCTION To the owner or user: The service manual you are reading is intended to provide you, and the maintenance or service technician with the information needed to install, start up, clean, maintain, and service this ice maker-dispenser. The ND750 ice making section is equipped with the following features: electronic controls for bin level and low water; thermostatic expansion valve; front service for most components; and R502 refrigerant. The ice dispensing section is a seamless plastic storage bin, with a stainless steel ice agitator at the bottom to sweep the ice into the dispensing chute. TABLE OF CONTENTS For the Installer Specifications . Page 15 Service Diagnosis Removal and Replacement Reservoir & Bin Controls . [. . . ] Note: Water filters can filter out suspended solids, but not dissolved solids. For more information on removal of these parts, see REMOVAL AND REPLACEMENT. /////////////////////////////WARNING/////////////////////////// Disconnect electrical power, and shut off the water supply. ////////////////////////////////////////////////////////////////////////// 1. Remove 3 hex studs holding ice chute cover to ice chute, and remove cover. Loosen band clamp under ice chute, and remove ice chute from evaporator. After the auger has been removed, allow the auger to dry: if the auger is not bright and shiny, it must be cleaned. Reverse to reassemble. BREAKER AND AUGER ASSEMBLY January, 1989 Page 17 ND750 SERVICE DIAGNOSIS: Condition - No Ice Being Produced STATUS: ICE MAKER DOES NOT OPERATE A. Check: The 3 reset switches, (circuit board, high and low pressure): depress and release each switch. If the still does not start, check: the spout switch; the high and the low side pressures. Check the low pressure cut out, if closed, go to E; if it is open, it could be due to: · Low refrigerant charge · The auger not turning · Restricted system · TXV not opening 1. Check the low side pressure, the low pressure cut out opens at pressure below 4 psig. Check if the auger is turning, if it is not, remove the gearbox and: Check for internal damage, repair and replace in the machine. Check for low charge, add some refrigerant, if the unit will operate, (normal low side pressure being about 30 psig) stop and look for a leak, repair, replace the drier, evacuate, and weigh in the nameplate charge. If, with added charge, the unit does not operate: Check for a restricted system, replace the drier, evacuate, and weigh in a nameplate charge. Check for a Thermostatic Expansion Valve that does not open, if defective, replace it. Check the high pressure cut out, if closed, go to F; if open: 1. The pressure control opens at 450 psig. Check the high side pressure, reset the control, and observe: on water cooled, that water soon begins to flow from the condenser drain; or, on air cooled, that the fan is forcing air through the condenser. If the unit trips out on pressures below 450 psig, replace the control. If the pressures rise above the trip out point, and the unit shuts down: a. Check for adequate water flow on water cooled, if adequate, clean the interior of the condenser. If the pressures are still too high replace the water regulating valve. [. . . ] Note: The case cover output gear, bearings, and shaft are one pressed together assembly. If the oil level and condition is acceptable, quickly check the gears and bearings. If there is evidence of water in the oil (rusty bearings and gears; the oil having a creamy white appearance; oil level too high) carefully inspect the bearings and gears. Note: The gears and bearings are available only as pressed together sets. [. . . ]