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Refrigeration Service

Offers solutions and expertise in servicing, repairing, and maintaining refrigeration systems to ensure performance and efficiency in various industries.

refrigeration

service

hvac

cooling

compressor

refrigerant

evaporator

condenser

thermostat

defrosting

air conditioning

maintenance

troubleshooting

repair

installation

ventilation

Refrigerant fluids are ___.

  • Fluids that absorb heat inside a cabinet
  • Fluids that release heat outside of a cabinet
  • Fluids that absorb heat outside of a cabinet
  • Both A and B

Which of the following is an HCFC refrigerant?

  • R-134a
  • R-11
  • R-22
  • All of the above

In a compression refrigerator, oil buildup can cause a problem in the ___

  • Crankcase
  • Evaporator
  • Motor
  • Oil separator

An evaporator made up of two or more pieces of sheet metal dimpled to create tubes is called a ____type.

  • stamped-plate

When using nitrogen, the nitrogen tank must be equipped with ___.

  • An automatic shot of valve
  • Low loss fitting
  • A regulator
  • A low pressure control

As the evaporator load increases, an automatic expansion valve will ____ to reduce the evaporator pressure while a thermostatic expansion valve will ____ to reduce the evaporator superheat.

  • close, open

Which of the following can be used to maintain the head pressure of a systemwith an air-cooled condenser?

  • Fan cycling
  • Condenser flooding valve
  • Dampers or louvers
  • All of the above

What could cause a compressor motor to burnout?

  • Moisture in the system
  • Dirt in the system
  • High temperature
  • All of the above

If an air-cooled condenser's fan motor stops running, the heat pressure will ____ and the amount of subcooling will ____.

  • increase, decrease

When a system with a water-cooled condenser cycles off, the water regulatingvalve should ____.

  • Remain open during the off cycle
  • Close, since the head pressure is lower
  • Open all the way to remove any residual heat
  • Re-calibrate itself to maintain the new lower head pressure

The two primary functions of an evaporator are to remove ____ and ____ from the refrigerated space.

  • moisture, heat
  • heat, moisture

What control determines the refrigerator cabinet temperature?

  • Motor control
  • Temperature control
  • Shutoff valve
  • High pressure switch

___ is a unit of electrical power.

  • Kilowatt
  • Volt
  • Ohm
  • Ampere

What indicates that correct brazing temperature has been reached?

  • The metal surface turns blue
  • A green color appears in the flame
  • The brazing alloy melts when held in the flame
  • The flux bubbles

A defrost system that pipes the compressor discharge vapor directly to the evaporator is called a ____ type.

  • hot gas defrost

The desired water flow through a condenser connecting to a recirculating water system is 3 gallons per minute.

  • True
  • False

If the application requires a coil design to operate below 32°F, there mustbe provision for ____.

  • Flooding the evaporator
  • Adding the evaporator
  • Defrost
  • Suction pressure control

Latent heat is ___.

  • Heat that can be measured
  • Heat that can be felt by touching it
  • Heat that changes a substance without changing its temperature
  • None of the above

The TX valve maintains a constant ____.

  • superheat
  • temperature

When should you install a new liquid line filter drier?

  • When a new compressor is installed
  • When the filter is clogged
  • Once a year during system maintenance
  • Both A and B

Ice formation on an evaporator is controlled by ___.

  • Manually shutting off the unit
  • The use of hot gas system
  • The use of electric heaters
  • All of the above

Blended refrigerant leak from a system ___.

  • Only if the line breaks completely
  • At a faster rate than other refrigerants
  • In uneven amounts due to different vapor pressures
  • At a slower rate than other refrigerants

If a low temperature evaporator is forming ice, which of the following is apossible problem?

  • Evaporator fan not running
  • Compressor not running
  • Condenser fan not running
  • No problem, ice formation normal

What kind of compressor motor control is used on household freezers?

  • Motor starting relay
  • Overload protector
  • Thermostat
  • All of the above

In an AEV or AXV system, when does the needle valve open?

  • This system has no needle valve
  • When the liquid level in the evaporator fails
  • When the compressor reduces the pressure in the evaporator
  • When the evaporator pressure is low and the temp is above normal

What is the definition of a BTU?

  • The amount of heat required to raise 1 lb of water 1 degree
  • The total amount of heat absorbed in a change of state
  • The amount of heat necessary to raise 1 lb of substance 1 degree
  • The total amount of heat to be removed from a given area in a specific time

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 wateris 85°F, which of the following is possible?

  • The outlet water will be 88°F.
  • The system head pressure will rise
  • The water regulating valve will close.
  • Both a and b are correct.

A compressor motor may be operated by ___.

  • Low pressure control
  • Temperature control
  • Both A and B
  • None of the above

Why are expansion valves adjustable?

  • To adjust fro different altitudes
  • To adjust for different types of refrigerants
  • To adjust for different sizes of liquid receivers
  • Both A and B

To test for shorts or grounds on the motor windings, use an ___.

  • High voltage test instrument
  • Ohmmeter
  • Voltmeter
  • Ammeter

How many different refrigerants may be recovered into the same cylinder?

  • Only two
  • Only three
  • Only one
  • Depends on the recovery machine

In a water-cooled condenser with dirty condenser tubes, the temperaturedifference between the refrigerant and the leaving water will be ____ when the tubes areclean.

  • Less than
  • Greater than
  • The same as
  • Slightly lower than

___ is a unit of electric current.

  • Kilowatt
  • Microfarad
  • Ampere
  • Volt

A water regulating valve helps maintain in a system's head pressure by modulating the flow of refrigerant through the condenser.

  • True
  • False

An air-cooled condenser that is operating in a climate that has four distinctseasons must ____.

  • Have some type of head pressure control
  • Use a water regulating valve
  • Have a multi-circuit evaporator
  • Operate with zero degrees of subcooling

Heat is absorbed by evaporating a liquid refrigerant in the ___.

  • Compressor
  • Condenser
  • Evaporator
  • Receiver

What is the common color used for ground wire?

  • Red
  • Black
  • Green
  • White

The capacity of an evaporator is affected by ____.

  • The saturation pressure of the low side of the system
  • The saturation pressure of the high side of the system
  • The amount of evaporator superheat
  • All of the above

The automatic expansion valve maintains a constant ____.

  • pressure

Where are piercing valves installed?

  • Suction line
  • Discharge line
  • Process tube
  • All of the above

Normal mid-temp refrigeration temperature is approximately __ degrees.

  • 32
  • 34
  • 40
  • 46

When the quantity of refrigerant flow to an evaporator is reduced, the amount of superheat in the vapor leaving the coil will ____.

  • rise

Which color cylinder designates R-22?

  • Sky blue
  • White
  • Light green
  • Yellow

Sensible heat is ___.

  • Heat that causes a change in temperature of a substance
  • Heat that you can feel by touching an object
  • Heat that you can measure
  • All of the above

The instrument used to find refrigerant leaks in a general area is called ___.

  • Electronic and ultrasonic leak detector
  • Halide leak detector
  • Fluorescent leak detector
  • All of the above

One large problem designer's face when designing air-cooled refrigeration and air conditioning equipment is a changing ambient from the changing seasons.

  • True
  • False

The state of the refrigerant entering the compressor is ___.

  • High pressure vapor
  • Low pressure vapor
  • Low pressure liquid
  • High pressure liquid

If an R-12 refrigeration system has its air-cooled condensing unit on a100°F roof and the condenser outlet temperature (refrigerant) is 115°F, with how muchsubcooling is the condenser operating?

  • 30°F
  • 15°F
  • 100°F
  • 130°F

A large capacity evaporator would probably have ____.

  • Stainless steel tubing
  • An excess of liquid refrigerant
  • An excess of vapor refrigerant
  • Multiple refrigerant circuits

Why is it that workers must wear goggles when operating a power grinder?

  • To protect their eyes from flying metal particles
  • To protect their eyes from the light
  • To protect their eyes from the heat
  • All of the above

If a spring pressure of a water regulating valve is increased, the system head pressure will also increase.

  • True
  • False

Which of the following is a refrigerant blend?

  • R-134a
  • R-22
  • R-409a
  • R-12

Which of the following is NOT part of the low side of the system?

  • Accumulator
  • Evaporator
  • Receiver
  • Suction line

Which of the following illustrates the principle of convection?

  • Movement of heat by fluid or air
  • Heat waves from the sun
  • Heat traveling through a solid object from end to end
  • Radiation from the sun

What force causes the solenoid valve to open?

  • Vapor pressure
  • Gravity
  • An electromagnet
  • A bimetal strip when heated

A forced draft medium temperature evaporator would ____.

  • Be defrosted by off-cycle defrost
  • Not need to be defrosted
  • Need electric defrost
  • Need a hot gas defrost

The water circuit in shell and coil and coil-type tube-in-a-tube condensers mustbe cleaned ____.

  • By removing the end caps
  • With a brush
  • Chemically
  • By air pressure

Which of the following refrigerants are not CFCs?

  • R-11
  • R-22
  • R-12
  • R-113

Fewer fins per inch on an evaporator allow more ice to build between defrost cycle.

  • True
  • False

If the waterflow is reduced, the temperature difference across a condenser will____.

  • Increase
  • Decrease
  • Remain the same
  • Correspond to the evaporator saturation temperature

In a water-cooled condenser, the leaving water temperature is normally ____°F lower than the condensing temperature of the refrigerant.

  • 10

What force causes a thermal-electric expansion valve to open?

  • Vapor pressure
  • Gravity
  • An electromagnet
  • A bimetal strip when heated

In a water-cooled condenser, a regulating valve is used to control the____.

  • Refrigerant flow through the pressure reducing device
  • Refrigerant condensing temperature
  • Suction pressure
  • Water temperature

Identify the starting relay or relays used on hermetic compressors

  • Current of potential
  • Thermal
  • Solid-state electronic
  • All of the above

If an R-12 refrigeration system is operating with a 25.4 psig suction pressure,what is the evaporator superheat if the evaporator outlet temperature is 34°F?

  • 9°F
  • 59°F
  • 34°F
  • 25°F

If a low temperature evaporator is forming excess ice, which of the followingcould be a possible problem?

  • The evaporator fan motor is defective.
  • The unit is not staying in defrost long enough.
  • The defrost heater is defective.
  • All of the above are correct.

Back seating the suction service valve will close the ___.

  • Compressor and gauge port
  • Compressor port
  • Gauge port
  • Suction line and compressor port

If an evaporator has a pressure drop of 10 psig and the low side pressure is 15psig, what is the pressure at the inlet of the evaporator?

  • 10 psig
  • 25 psig
  • 15 psig
  • 5 psig

In order for a flooded condenser type head pressure control system to operate, a device called a ____ has to be added to the system because of the extra refrigerant.

  • receiver

The instrument used to measure ohms is called ___.

  • Ammeter
  • Voltmeter
  • Ohmmeter
  • None of the above

The component that changes the low-pressure vapor to a high-pressure vapor is ___.

  • Condenser
  • Evaporator
  • Compressor
  • Capillary tube

Why should refrigerant cylniders be filled to only 80% or capacity?

  • Liquid refrigerant expands with an increase in temperature
  • A cylinder completely filled liquid will burst if it warms up
  • Liquid refrigerant will foam in the cylinder
  • Both A and B

The device used to feed refrigerant to multiple circuits in an evaporator is called a flow circuit.

  • True
  • False

Bimetal switches will open if ___.

  • The current load is too high
  • There is poor air circulation
  • There is poor refrigerant circulation
  • Both A and B

Condensing temperatures in an air-cooled condensing unit can be reduced by____.

  • Increasing the condensing surface area
  • Increasing the cfm through the condenser
  • Decreasing the temperature of the air entering the condenser
  • All of the above

Every central split cooling system manufactured in the USA today must have a Seasonal Energy Efficiency Ratio (Seer) of at least 10.

  • True
  • False

Why is it necessary to be cautious when handling contaminated refrigerant oil?

  • It may be toxic
  • It may be acidic
  • It may stain your clothes
  • All of the above

A normally operating water-cooled condenser is operating with a 10°differential between water in and water out. If the amount of 85°F water going through thecondenser is reduced, which of the following is a possible temperature of the water leaving thecondenser?

  • 75°F
  • 0°F
  • 95°F
  • 105°F

What is the most common metering device used in domestic refrigerators?

  • Thermostatic expansion valve
  • Automatic expansion valve
  • Capillary tube
  • High-side float

If a high temperature evaporator is forming ice, which of the following is apossible problem?

  • Evaporator fan not running
  • Compressor not running
  • Condenser fan not running
  • No problem, ice formation normal

When brazing a suction line using sil-flux, you should

  • Use alcohol to clean the copper tubing
  • Use sand paper to clean the copper tubing
  • Always flux the copper tubing
  • None of the above

What does the sight glass in the liquid line frequently indicate?

  • Low refrigerant
  • Moisture in the system
  • Refrigerant flow
  • Both A and B

The shell and tube condenser is cleaned ____.

  • With a brush after removing the end caps
  • Only with chemicals
  • With compressed air
  • With a vacuum cleaner

When evacuating a refrigeration system, the vacuum pump should be able to pull

  • A vacuum of 1000 microns
  • A vacuum of 2 microns
  • A vacuum of 500 microns
  • A vacuum of 5 microns

What is the advantage of a water-cooled condenser?

  • It has a lower operating pressure
  • It provides greater system capacity
  • It reduces wear on the system's moving parts
  • None of the above

A typical evaporator operating temperature in an air-conditioning system is____.

  • 40°F
  • 55°F
  • 75°F
  • 200°F

The condenser in a refrigeration system ____.

  • Desuperheats the vapor from the compressor
  • Condenses the vapor from the compressor
  • Subcools the liquid refrigerant before it leaves the condenser
  • All of the above

The four most important components in a refrigeration system are:

  • Compressor, Accumulator, Receiver, Evaporator
  • Evaporator, Condenser, Receiver, Compressor
  • Compressor, Metering Device, Condenser, Evaporator
  • Metering Device, Compressor, Condenser, Filter-drier

Front seating the suction service valve will close the ___.

  • Compressor port
  • Compressor and gauge port
  • Suction line port
  • All of the above

What is the purpose of an oil separator?

  • Remove the oil from the refrigerant
  • Cool the refrigerant from the compressor
  • Cool the oil in the condenser
  • None of the above

High head pressures from low ambients can cause insufficient refrigerant flow rates through metering devices, which in turn starve evaporators.

  • True
  • False

The instrument used to measure current is called ___.

  • Ammeter
  • Ohmmeter
  • Voltmeter
  • Wattmeter

Moisture in the system will result in

  • Motor overheating
  • Blocked filter-drier
  • High discharge pressure
  • All of the above

Why do some technicians use the reamer to clean the end of the copper tubing?

  • To restore full wall thickness
  • To remove the burrs
  • Only aluminum tubing should be burred
  • All of the above

At what temperature does silver solder melt?

  • 1300 degrees
  • 1600 degrees
  • 1100 degrees
  • 450 degrees

The start capacitor is connected in ___ with the start winding.

  • Series
  • Parallel
  • Reverse
  • Both A and B

What refrigerant have the greatest negative effect on the ozone?

  • CFC
  • HCFC
  • Azeotropic
  • All of the above

Excess evaporator superheat ____.

  • Is desired to prevent liquid from entering the compressor
  • Will reduce the cooling capacity of the system
  • Can be removed by removing refrigerant from the system
  • Will cause the system to go into defrost

The device that changes liquid to vapor is called?

  • Compressor
  • Condenser
  • Evaporator
  • Metering device

In the TEV or TXV system, when does the needle valve open?

  • This system has no needle valve
  • When the liquid level in the evaporator fails
  • When the compressor reduces pressure in the evaporator
  • When the evaporator pressure is low and the temp is above normal

SEER is calculated based on the total amount of ____ the system will provide over the entire season, divided by the total number ____it will consume.

  • cooling in Btu, watt-hours

What instrument is used to measure voltage?

  • Ammeter
  • Ohmmeter
  • Voltmeter
  • All of the above

Heat may be transferred from one body to another by ___.

  • Radiation
  • Conduction
  • Convection
  • All of the above

As a rule of thumb, the temperature of the evaporator should be about ____ °F colder than the box temperature.

  • 15

At what temperature does 95/5 soft solder melt?

  • 1100 degrees
  • 450 degrees
  • 800 degrees
  • 1300 degrees

In most cases, the refrigerant leaving the evaporator must be ____ percent vapor.

  • 100

Which of the following would allow a system to operate more efficiently?

  • Condenser that had refrigerant leaving with 10°F of superheat
  • Condenser that had refrigerant leaving with 15° of subcooling
  • Condenser that had refrigerant leaving as 100% vapor
  • Condenser that had refrigerant leaving with 10° of subcooling

Which color cyliner designates R-134a?

  • Yellow
  • Green
  • Sky Blue
  • Light green

In a refrigerator that has capillary tube, what controls the box temperature?

  • Sensing bulb
  • Low pressure control
  • High pressure control
  • Temperature control

An evaporative condenser uses ____ and ____ as the transfer medium for system heat.

  • air, water
  • water, air

A typical superheat for an evaporator operating under normal conditions would be____.

  • 14 to 16°F
  • 4 to 6°F
  • 8 to 12°F
  • 6 to 8°F

Refrigeration contaminants are removed by ___.

  • Oil separation
  • Filtration
  • Both A and B
  • None of the above

Refrigerant entering the evaporator is approximately ____% liquid.

  • 75

The refrigerant in the evaporator must be colder than the air passing over it for heat to transfer to the evaporator.

  • True
  • False

A stamped plate evaporator usually does not use a fan to move air across it.

  • True
  • False

The heat required for off-cycle defrost is obtained from ____.

  • Supplemental electric heat when the system is shut down
  • Hot gas when the system is operating
  • The space temperature when the compressor is off

When should you push and pull on a wrench?

  • Push to loosen, pull to tighten
  • Pull to loosen, push to tighten
  • Always push
  • Always pull

A refrigeration system designed for the storage of flowers or candy isconsidered a ____ type.

  • High temperature
  • Medium temperature
  • Low temperature
  • Sharp freezing

Refrigeration service valve wrench is used to __.

  • Front sit the valve
  • Back sit the valve
  • Mid position the valve
  • All of the above

Low suction pressures, iced coils, short-cycling, and inefficient cooling can also result from low head pressures.

  • True
  • False

Evaporating pressure must be ___ so the liquid boils at the correct temperature.

  • Low enough
  • High enough
  • Twice the low-side pressure
  • None of the above

How many electrical terminals does a hermetic compressor motor have?

  • One
  • Two
  • Three
  • Four

Which of the following is an HFC refrigerant?

  • R-12
  • R-22
  • R-134a
  • R-123

A gauge manifold includes a ___.

  • Center gauge
  • High side gauge
  • Low side gauge
  • High side and low side gauge

___ is a unit of capacitance.

  • Kilowatt
  • Microfarad
  • Milliamps
  • Volt

What trouble may be an indication from a warm suction line?

  • An excess of high-pressure liquid in the evaporator
  • An excess of refrigerant in the system
  • A shortage of refrigerant
  • Any of the above

What can be used to maintain the head pressure of a system with a water-cooledcondenser?

  • Fan cycling
  • Dampers or louvers
  • Water regulating valve
  • All of the above

Evaporative condensers operate more efficiently in climates where the wet bulb temperature is a great deal lower than the dry bulb temperature.

  • True
  • False

When brazing a discharge filter-drier, you should always

  • Flux it
  • Use sand paper to clean it
  • Clean it
  • All of the above

A hermetic system is a ___

  • Motor and compressor in a dome
  • Compressor that is belt driven
  • Direct-drive motor
  • Hermetic split-phase induction motor

Which type of compressors use crankshaft seal?

  • Semi-hermetic
  • Open-type
  • Scroll
  • Rotary

Mineral deposits in the water portion of a water-cooled condenser act as____.

  • A conductor of heat
  • An insulator
  • A cleaning solution
  • They have no effect on the operation of the condenser.

At what temperature does sil-flux melt?

  • 1100 degrees
  • 1800 degrees
  • 1300 degrees
  • 800 degrees

What instrument is used to measure the temperature?

  • Anemometer
  • Monometer
  • Thermometer
  • Tachometer

___ is a unit of electromotive force.

  • Kilowatt
  • Microfarad
  • Milliamps
  • Volt

What do we use to pinpoint a refrigerant leak in the system?

  • Electronic and ultrasonic leak detector
  • Soap solution
  • Halide leak detector
  • None of the above

The correct term for a coil using a low side float is ____.

  • flooded

What is the purpose of a sight glass on a compressor?

  • To check the moisture content
  • To check the oil level
  • To check the low-side pressure
  • All of the above

Heat flows in what direction?

  • Cold to warm
  • Warm to cold
  • Liquid to gas
  • All of the above

Automatic expansion valve usually adjusts the ___.

  • Temperature in the cabinet
  • Temperature in the evaporator
  • Pressure in the evaporator
  • Both B and C

The low form of plant life that grows in condenser water is ____.

  • algae

What indicates an electrical failure in a door mullion heater?

  • Frozen to cabinet
  • Sweats
  • Electrical shock
  • Alll of the above

Which of the following condensers is the most efficient?

  • Forced draft air-cooled
  • Induced draft air-cooled
  • Water-cooled parallel flow
  • Water-cooled counter flow

What is the purpose of a ladder diagram?

  • To identify actual location
  • To help troubleshoot a system
  • To provide a standard electrical circuit diagram
  • All of the above

What leaves the refrigerant system when you purge the lines?

  • Refrigerant
  • Moisture
  • Oil
  • All of the above

Why do most domestic refrigerators have a defrost system?

  • Frost buildup corrodes the evaporator tubing
  • Frost buildup can squeeze the tubing closed
  • Frost buildup on evaporator reduces efficiency
  • All of the above

What is the definition of sub-cooling?

  • Cooling liquid refrigerant below its condensing temperature
  • Cooling liquid refrigerant above its condensing temperature
  • Cooling vapor refrigerant below its condensing temperature
  • Cooling vapor refrigerant above its condensing temperature

If the suction line is frosted, the trouble could be ___.

  • A shortage or refrigerant
  • Too much refrigerant
  • A broken thermostat
  • Both A and B

The two pressures that push to close a thermostatic expansion valve are the ____ pressure and the ____ pressure.

  • spring, evaporator

During the defrost cycle of a forced draft low temperature evaporator, the evaporator fan would ____.

  • Remain on to speed up the defrost
  • Turn off
  • Cycle with the condenser
  • Cycle with the compressor

Control of the head pressure in an air-cooled condenser is done by ____.

  • Cycling the condenser fan
  • Controlling dampers in the airstream through the condenser
  • Flooding the condenser with refrigerant
  • All of the above

Non-condensibles in a refrigeration system will result in

  • Higher suction pressure
  • Lower discharge pressure
  • Higher discharge pressure
  • Lower suction pressure

It is said that most accidents are being caused by

  • Carelessness
  • Lack of knowledge
  • Stupidity
  • None of the above

What is the definition of super heat?

  • The temperature of vapor below its boiling point as a liquid
  • The temperature of vapor above its boiling point as a liquid
  • The temperature of vapor below its condensing point
  • None of the above

Refrigerant in a system should be disposed of by ___.

  • Venting it into the air
  • Bleeding off some of the charge into the air and recovering the remainder
  • Using recovery/recycling equipment
  • None of the above

The device that changes low pressure vapor to high pressure is called?

  • Metering device
  • Open-type
  • Condenser
  • Compressor

What type of valve is used to reverse the flow of refrigerant in a heat pump?

  • Suction pressure valve
  • Check valve
  • Thermostatic expansion valve
  • 4-way solenoid valve

In a hot gas defrost system, which part of the system is heated?

  • Condenser
  • Drain pan
  • Evaporator
  • Both A and B

The refrigerant in a condenser in a refrigeration system ____.

  • Absorbs heat
  • Gives up heat
  • Changes to a vapor
  • Is under lower pressure than the evaporator

When the velocity of the air moving over an evaporator is slow, the "air film" acts as an insulator and slow the rate of heat exchange.

  • True
  • False

Hard starting may also occur in a low ambient conditions causing low head pressures.

  • True
  • False

A direct expansion-type evaporator is also called a ____.

  • Flooded evaporator
  • Dry-type evaporator
  • Multi-circuit evaporator
  • Stamped evaporator

Refrigerants can be mixed in the recovery cylinder.

  • When you do not know what type of refrigerant you are recovering
  • All the time if the refrigerant cylinder is marked
  • Never
  • Only when the refrigerant is going to be reused

Thermistors are used in refrigeration work ___.

  • To measure temperatures
  • To protect an overheated motor from burning up
  • As a temperature-operated electric circuit control
  • None of the above

Loose or dirty connection on a fan motor can cause ___.

  • Voltage drop
  • Faster speed
  • Voltage increase
  • Both B and C

After installing a new compressor, the unit should first be

  • Pressurized with nitrogen and leak checked
  • Pressurized with nitrogen and a trace of R-22 or R-134a
  • Pressurized with R-22 and leak checked
  • Pressurized with R-12 and leak checked

Compressor, fan and pump motors should be regularly cleaned to___.

  • Remove dust
  • Provide proper air circulation
  • Remove lint
  • All of the above

A forced draft high temperature evaporator would ____.

  • Have its fins very close together
  • Not need to be defrosted
  • Need a hot gas defrost
  • Both a and b
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