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50 Cards in this Set
- Front
- Back
Furnace _______ is controlled by using two stages of electric heating elements. |
Capacity |
|
At designed operating conditions, the standard A/C system will operate with an evaporator saturation point of _______ degrees F. |
40 degrees F |
|
A normal evaporator superheat at the evaporator outlet in a standard efficiency A/C system operating under design conditions will be _______ degrees F. |
10 degrees F |
|
A more accurate rating system for A/C equipment that takes into consideration operation during the complete cycle is the __________ standard. |
Seer |
|
Since the evaporator absorbs both sensible and latent heat, humidity must be taken into account and considered part of the load on the evaporator. True or False? |
True |
|
A typical evaporator operating temperature in an air conditioning system is? |
40 degrees F |
|
The refrigerant leaving the compressor is referred to as: |
Superheated gas |
|
When transferring refrigerants from a cylinder to a refrigeration system or any other container, you should always wear: |
Goggles with side shield and gloves |
|
R-134A Is an example of a ___________ refrigerant. |
Pure |
|
The refrigerant in a condenser In a refrigeration system: |
Gives up heat |
|
The condenser in a refrigeration system: |
All the above |
|
If a high temperature evaporator forms ice, which of the following is a possible problem? |
Evaporator fan not running |
|
The refrigerant in the evaporator must be colder than the air passing over it for heat to transfer to the evaporator. True or False? |
True |
|
The shell of a hermetic type of reciprocating compressor is in the Iowpressure side of the system. True or False? |
True |
|
The purpose of a capillary tube is to: |
All the above |
|
When the load on the evaporator increases, the TXV valve: |
Increases the flow of refrigerant |
|
What would happen of the fan on an electric unit heater burned out? |
Both A and B are possible |
|
Technician ”A” says that a fusible link can he jumped out temporarily to allow the customer to get heat until the next business day. Technician “B" says that if the fusses keep on blowing on an electric duct heater, the fan may be defective. Which of the following statements is correct? |
Technician A is wrong, Technician B is correct |
|
If a duct mounted electric heater is to be installed and it is discovered that the heater is too long to fit inside the duct (the duct is 10" high and 14" wide and the heater is 9 1/2" high and 18" long), what can the technician do to properly complete the installation? |
Return the heater |
|
The resistance wire used In electric heating elements ls usually: |
Nickel Chromium |
|
An electric heating unit in a duct system Is classified as a: |
Forced draft convection |
|
The limit switch is used on the electric element assembly to: |
Open the circuit to the element if the furnace overheats |
|
An electronic charging scale measures the weight of refrigerant into a refrigeration system. True or False? |
True |
|
R-410A refrigerant should be used for? |
New equipment |
|
For maximum element life, the element must have sufficient air over all parts of the element to prevent any part of the element from glowing red. True or False? |
True |
|
To speed up the recovery time a technician should place the bottle ______________. |
In bucket of ice |
|
Which element in refrigerant destroys the ozone? |
Chlorine |
|
On a split air conditioning system with a remote condensing unit, which refrigerant lines must be field Installed? |
Liquid and suction line |
|
The solar load on a structure Is the heat gain resulting from the: |
Heat radiation from the sun |
|
Temperature Glide occurs only with ___________. |
Zeotrope |
|
With a rise In suction gas temperature entering the compressor, the temperature of the hot gas In the compressor discharge line will: |
Rise |
|
It Is possible that your hand wouId suffer frostbite If it comes in contact wuth Iiquid R-22 when disconnecting your hoses from a system. True or False? |
True |
|
Which of the following terminal combinations would show an open circuit if the internal overload device in a hermetic compressor should open due to excessive heat? |
Both A and B |
|
The capacity of an evaporator is affected by. |
All the above |
|
The sequencer uses a 24 volt coil to close a set of switches. True or false? |
False |
|
When recovering refrigerant from a unit, how much liquid can be placed in a recovery bottle? |
80% |
|
A dirty condenser coil can lead to: |
Both B and C |
|
Why must technicians recover refrigerant? |
It's the law under title 608 of the clean air act |
|
In reciprocating and scroll type motor compressor assemblies, the motor is cooled by: |
Suction gas returning to the compressor |
|
Reciprocating compressors of less than _____ Horse Power do not us piston rings. |
10 |
|
Low pressures with low superheat Is an indication of______________. |
Indoor airflow problems |
|
Completely clogged air filters can lead to: |
All the above |
|
If the blades on a centrifugal (evaporator) blower become clogged with dirt, which of the following ls likely? |
Both A and B |
|
An increase In Subcoollng In the liquid line will result In: |
Decrease in superheat |
|
Which would not cause high discharge pressure In the condenser: |
Refrigerant undercharged |
|
Flash Gas occurs In: |
Evaporator |
|
The evaporator in a refrigeration system: |
Absorbs heat from the conditional space |
|
When the evaporator load decreases, what happens to the suction pressure? |
Decreases |
|
High superheat In the evaporator can be caused by: |
A low refrigerant charge |
|
The most common metering device in air conditioning is? |
The TXV |