This article is part two of a two-part series on ice flake machine troubleshooting. The last article, which appeared in the Feb. 7 NEWS, examined troubleshooting low and high water levels. This article will examine water impurities and mechanical problems.
When water is frozen in an evaporator flooded with water, minerals in the water will often build up on the walls of the evaporator. This mineral buildup will cause added resistance for the ice cutting auger. Mineral buildup (scale) is a porous material and is a good insulator to heat transfer. The refrigerant will now see less heat load from the water in the cylinder and the evaporator pressure will drop. A drop in evaporator pressure will cause a colder evaporator and harder ice. The cutting auger’s flights now has to cut harder ice along with mineral that have built up on the evaporator surface. The result is a loud crunching or squealing noise coming from the evaporator compartment. This added resistance of cutting ice and mineral buildup will also add extra load on the gear motor. A higher amp draw will be the result.
DRIVE TRAIN (GEARS AND SHAFTS)When the ice-cutting auger is stressed, so is the gear motor and drive train. The ice-cutting auger, drive train with gears, and the gear motor are all connected (Figure 1). When the gear motor is stressed from cutting hard ice and minerals, the extra torque generated from the motor will cause excessive heat. This may cause the gear motor’s overload to open and shut the unit down until a service person manually resets the overload on the gear motor. Cleaning the ice flake machine according to the manufacturer’s recommendations with an approved cleaner, and inspecting the bearings connecting the cutting auger with the drive train will prevent mineral buildup on the freezing cylinder’s surface and keep the ice flake machine operating quieter and longer.
Often, grease can leak out of a bearing housing and start a bearing failure. If a bearing has started to fail, the cutting auger may wobble from the added clearance in the worn bearing. This wobbling as the auger rotates may cause the auger to touch the freezing cylinder (evaporator) and scar its surface. If scarring of the evaporator surface or auger’s cutting surface has occurred, one of the components will, for sure, have to be replaced. Always follow the manufacturer’s recommendation when replacing a cutting auger or freezing cylinder. It is this gear motor assembly that is more susceptible to failure than any other part of the ice flake machine.
Remember, as the auger rotates and cuts ice and mineral deposits, the gear motor and gear assembly senses all of these stresses and strains. It is for this reason that some manufacturers have manufactured open-type gear case housing assemblies. This means the gear assembly has a vent and is exposed to the atmosphere, usually with a soft plastic plug holding the gear lube (grease) from escaping. When excessive heat occurs from gear motor stress, expanded hot grease can escape through the vent. However, one has to be careful to keep the vent hole plugged or moisture can enter. This will deteriorate the lubricating effect of the grease, and excessive gear wear will result.
Usually, a regular clicking sound will be heard from the drive train if a gear is chipped from poor lubrication or too much stress. However, if the auger motor is starting to fail, a loud, higher pitch noise will be heard. Cleaning the ice flake machine with an approved cleaner and inspecting the bearings connecting the cutting auger with the drive train will prevent mineral buildup on the freezing cylinder’s surface and keep the ice flake machine operating quieter and longer.
Publication date: 04/04/2011