User manual SCOTSMAN NDE750

[. . . ] NDE750 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 NDE750 is a combination nugget ice maker and countertop dispenser. The NDE750 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 R-404a (HP62) 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 . [. . . ] Check: The reset switches, (high and low pressure): depress and release each switch. If the machine still does not start, check: 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 38 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 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. If the air flow is poor because of the installation, advise the user that the unit should be moved, or the air around it kept cooler. Check that the fan blades are clean, and the fan secure to the fan motor shaft. The machine will not run if there is not enough water in the reservoir. See the next step. December 1993 Page 18 NDE750 SERVICE DIAGNOSIS: Condition - No Ice Being Produced STATUS: ICE MAKER DOES NOT OPERATE G. Check: The gear motor, if it will not run, the compressor will not run. If no power to it: Check: The indicator lights on the circuit board, the bin empty light should be ON, the no water light should be OFF . If the line side has the correct voltage and the load side does not, replace the transformer. If the transformer is good, and the bin empty light is OFF, check the ice level sensors. Look through the ice chute "eye" hole for something blocking the ice chute. [. . . ] (DEG F) 70 72 74 76 78 80 82 84 86 88 90 92 94 96 98 100 102 104 106 108 110 112 114 116 118 120 122 124 126 128 130 132 134 136 138 140 142 144 146 148 VAPOR PRESSURE (PSIG) 146 150 155 161 166 171 177 182 188 194 200 206 212 219 225 232 239 246 253 260 268 275 283 291 299 307 316 324 333 342 351 360 370 379 389 399 409 420 430 441 December 1993 Page 29 NDE750 REFRIGERATION SERVICE General Information: Work on the refrigeration system should only be done when it is certain that the system needs repair. · Refrain from checking refrigeration pressures without reason. Visual inspection of the water system, observation of the ice formation, amp draw, voltage, and other techniques will lead to proper diagnosis. Scotsman also recommends that, at the time of initial start up, gauges not be used. [. . . ]