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HVR 140 Final
Terms in this set (50)
The process of removing heat from a place where it is not wanted and transferring that heat to a place where it makes little or no difference is known as
The boiling temperature and its relationship to the system exists in the
__________ is the best method of checking to see when a refrigeration coil has a proper level of refrigerant
If the application requires a coil design to operate below freezing, there must be provision for
A normally operating water-cooled condenser is operating with a 10° differential between water in and water out. If scale forms on the water tubes and the entering water is 85°F, which of the following is possible?
The outlet water temperature will be lower than expected.
The system head pressure will rise.
In a water-cooled condenser, a regulating valve is used to control the
refrigerant condensing temperature
An air-cooled condenser that is operating in a climate that has four distinct seasons must
have some type of head pressure control
Rotary compressors are used primarily in
residential air conditioning
The clearance volume of a compressor cylinder is the
volume of the space between the bottom of the valve plate and the top of the piston at the top of the stroke
If a thermometer expansion valve's thermal bulb came loose from the suction line at the outlet of the evaporator, which of the following could result?
The bulb pressure would increase and the thermostatic expansion valve would open
The superheat in the evaporator would decrease
Liquid refrigerant would flow back to the compressor
The pressure limiting TXV
limits the refrigerant flow rate to the compressor capacity
Random defrost is accomplished
when the refridgeration system has enough reserve capacity to cool more than the load requirement
In a kitchen, _________ condensing units may be easier to maintain
The three-way heat reclaim valves in most heat reclaim systems are ____________ operated.
The heat reclaim valve is a three-way valve that is ____________ operated
When a parallel heat reclaim system is used, the heat reclaim condenser must be sized to handle ___________% of the refrigeration system's rejected heat when in the heat reclaim mode.
Knock-down walk-in coolers are constructed of panels from____________ thick.
1 in. to 4 in.
In condensate removal, the drain lines should be sloped downward about__________ in. per foot for proper drainage.
When using precharged tubing in refrigeration piping, it is called a
____________ coolers are used to cool either canned or bulk beverages
Carbonation of cold drinks is accomplished by injecting __________into the drink from a small cylinder inside the vending machine
_________-type water cooler systems require less maintenance because they are automatic in their dispensing of water
The________ is the only special part of the refrigeration system
Drinking water is called ___________ water.
It is estimated that ___________% of the water dispensed in a bubble for drinking goes down the drain.
When air from the atmosphere is compressed for use, the air must be _____________.
Most package ice makers are ____________ cooled.
____________ ice is normally made in a vertical refrigerated cylinder surrounded by the evaporator on the outside.
The auger in a flake ice maker has cutting surfaces called
A _____________ is used to turn the auger in a flake ice machine
Most ice flakers have a _________ that reduces the auger drive motors speed from 1725 rpm to 9 to 16 rpm
gear reduction drive
__________ evaporators have ice cups designed to cause the ice to fall out of the cups during defrost
____________ ice cube machines usually have vertical evaporator plates with water flowing over the individual cells
___________ between the evaporator cells allow air entering from the edges of the ice to travel along the entire ice slab and relieve the suction force
_________ are simply small computers that contain stored programs or algorithms
For maximum efficiency, individual ice machine models have different programs called ________ values
Microprocessors are often referred to as.
integrated circuit controllers
Many filter manufacturer use _____________ to inhibit calcium or lime scale buildup
Most packaged ice machines are designed to be located in ambient temperatures of
40 degrees F to 115 degrees F
The refrigerated cabinet temperature of a high-temperature refrigeration unit ranges from
45°F to 60°F
In a high-temperature refrigeration unit, the boiling point of the refrigerant in the coil is normally ____________ lower than the cabinet temperature
10°F to 20°F
The process of ice making usually occurs in which temperature range?
5°F to 20°F
Condensing units located outside that are required to operate year-round must have __________.
head pressure control
With the entering air to the condenser above 70°F, the temperature difference between the outdoor air and the condensing temperature on standard units will be
25°F to 30°F
An air cooled R-12 refrigeration system is operating normally with a suction pressure of 25 psig and a head pressure of 136 psig. Which of the following represents a possible set of operating pressures if the condenser fan motor burns out?
high side 180 psig, low side 35 psig
In a wastewater system, the water entering the condenser is 85°F and the water leaving the condenser is 105°F. Which of the following statements is a logical explanation for the above conditions?
reduced water flow through the condenser
In a wastewater system, the water entering the condenser is 85°F and the water leaving the condenser is 90°F. Which if the following statements is a logical explanation for the above conditions?
water regulating valve stuck in the wide-open position
excess water flow through the condenser
In a wastewater cooled system, the difference between the condensing temperature of the refrigerant and the leaving water temperature is approximately_____________.
In a water-cooled condensing unit/cooling tower combination, the temperature difference of the water through the condenser will be approximately _____________.
The approach of the cooling tower is the
difference in temperature between the entering air wet-bulb temperature and the sump water temperature
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