User manual SCOTSMAN NM952

[. . . ] NM952 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 system. The NM952 is a modular ice system that fits a variety of Scotsman ice storage bins. It features: front service for the freezer, gearmotor, control box, water reservoir, and bin control; an electronic circuit for monitoring ice and water level; a thermostatic expansion valve; and R-22 as the refrigerant. TABLE OF CONTENTS Installation For the Installer Specifications . 3 Two units on one bin . . . . . . . . . . . . . . . . . . . . . . . . . . . [. . . ] Check for a Thermostatic Expansion Valve that does not open, if defective, replace it. Replace the drier, recover, evacuate, and weigh in the nameplate charge. E. Check the high pressure cut out, if closed go to F, if open check 1. 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 400 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. Check for adequate air flow on air cooled. Clean the condenser and (if used) the filter. 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 the fan motor for tight bearings and proper rotation. Check that the fan blades are clean, and the fan secure to the fan motor shaft. Check the spout switch (a manual reset). It opens from excess pressure of ice inside the ice chute: this should only happen when the machine does not shut off when the ice storage bin is full. The machine will not run if there is not enough water in the reservoir. See the next step. August 1993 Page 19 NM952 SERVICE DIAGNOSIS: Condition - No Ice Being Produced STATUS: NOTHING OPERATES H. 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 bin empty and no water lights are off, check the transformer. Transformer "load" side should have 12 to 15 volts. If not, check the "line" side. [. . . ] · Although this system uses R-22, it must not be vented to the atmosphere. · This system has a critical charge, it must be recharged with the correct amount of refrigerant as listed on the nameplate of the ice machine, or performance will suffer. · Anytime the refrigeration system has been opened, the dryer should be replaced. August 1993 Page 29 NM952 CIRCUIT BOARD TESTING ///////////////////////////////////////////////////////////////////////WARNING////////////////////////////////////////////////////////////////// These procedures require the machine to be connected to the power supply. The voltages of the electronic circuit are very low, but HIGHER VOLTAGES ARE PRESENT IN THE UNIT. [. . . ]