HVAC Unit 27 Commericial Ice Machines Review Questions
List two causes that may lead to auger wobble.
- Grease leaking out of the steel roller bearings and causing overheating of the bearings. - Worn bearings pg 588
Ice production in an ice flake machine depends mainly on two factors. Name and briefly explain these two factors.
- Inlet water temperature - Ambient temperature around ice machine pg 592
Name and explain three types of ice bin controls in ice flake machines.
- Mechanical flapper-type device - they sense backed up ice by pressure and control a microswitch - Infrared electric eye - two infrared sensors mounted on the outside of the ice chute's base. When the ice builds up and blocks the bath of the sensors, the ice maker shuts down. - Sonar - uses sonic or sound waves and vibrations to sense ice pg 590
Water conditions can be broken down into three categories. Name these categories.
- Suspended solids - Dissolved minerals and metals - Chemicals pg 620
What would be the symptoms of a defective float on an ice maker?
- There may be a manual reset overload in the gear motor. If this button has to be reset often, there may be a problem with the float. - If there is too much water, it may overflow the evaporator - If there is not enough water, the ice may be too hard and the ice maker may be inefficient. - If the the auger freezes to the evaporator, the water level may be too low. pg 586
Why do ice machines need to be cleaned periodically?
A cleaner ice machine will produce harder ice. A cleaner machine eliminates minerals and improves ice quality. pg 619
Sand and dirt in water are usually easily removed by? ABCD
A) Filters pg 620
A measurement that represents the thermal cooling capacity of ice and also represents the amount of calcium and magnesium in water is? ABCD
A) Hardness pg 618
What is the common troubleshooting technique used on microprocessors? ABCD
A) Input/output troubleshooting pg 611
A method for killing bacteria, viruses and protozoa in ice machines is? ABCD
A) Sanitizing pg 620
Which part of an ice flake machine is most prone to failure? ABCD
A) The gear motor. pg 587
Most of the time, the input signals to a microprocessor are? ABCD
B) Low Voltage pg 613
A buildup of minerals that forms a flaky coating on the surface of the evaporator and water system is called? ABCD
B) Scale pg 618
A way in which a microprocessor communicates to a service technician about a certain malfunction in the ice machine is? ABCD
B) an error code pg 614
Which type of ice is made using a gear motor and auger? ABCD
C) Flake ice pg 585
What is the most common type of defrost during a harvest cycle for an ice maker? ABCD
C) Hot Gas pg 600
One of the quickest and most throrough ways of obtaining technical service information for an ice machine is through the ? ABCD
C) Internet pg 613
T or F: The same solution can be used to clean and sanitize an ice machine.
False- two different solutions are needed. Cleaning solution removes scale deposits. Sanitizing kills bacteria. pg 620
Which type of ice maker has a continuous harvest cycle?
Flake ice maker. pg 585
Explain how liquid floodback to the compressor may occur during a hot gas defrost period with ice makers.
If there is no suction-line accumulator, liquid refrigerant may reach the compressor and cause compressor damage. pg 604
What is the function of the ice thickness probe in an ice maker?
It allows the adjustment of the ice bridging. pg 596
Explain the function of the centrifugal pump in ice makers.
It delivers water to more than one evaporator. pg 596
Why do ice machines need to be santized periodically?
It helps to eliminate harmful bacteria that tend to thrive in the ice-making environment. pg 620
Explain what is meant by ice bridging in a cell-type ice maker.
It is the edging of the individual cells that grows to form one large ice slab the size of the evaporator. pg 596
What are the two functions of the dual float switch in an ice flake machine?
It maintains the proper level of water in the reservoir and provides for an ice machine shutdown in case of a low-water level situation. pg589
Explain the function of the water dump solenoid valve in an ice maker.
It purges the water from the sump and gets rid of any residual minerals from the previous freeze cycle which is very important for clear hard ice. pg 600
Explain the function of weep holes on the evaporator of a cell-type ice maker.
They are located between the evaporator cells and allow air to enter from the edges of the ice to travel along the entire ice slab and relieve the suction force. pg 607
T or F - Stainless steel is often used on a evaporators because it is durabl, it is very sanitary and it resists corrosion.
True pg 594
T or F: Entering-air temperature and water temperature are the main factors for determining the amount of ice produced in an air-cooled ice machine.
True pg 615
T or F: Chemicals in the water have to be removed with carbon filtration.
True pg 620
T or F: Cleaning with an approved ice machine cleaner is a method of removing scale from an ice machine.
True pg 620
T or F: A common type of water filtration and treatment for ice machines is a triple-action filter system.
True pg 621
What is the function of a flush cycle for an ice flake machine?
When water freezes, minerals are left behind and can build up in the evaporator freezing cylinder. A flush will remove the minerals on a periodic basis. pg 590
