Module 2 Test Cooling Study Cards

Question 1

List 10 items that affect the amount of air conditioning needed in a home.

Answer 1

outdoor temp, outdoor humidity, insulation levels, single/double/triple window panes, whether windows are low e, window coverings open/closed, amount of shade from trees, roof overhang, awnings, amount heat generated inside by people, amount of east/west facing glass.

Question 2

How many square feet can one ton of A.C. cool in Florida?

Answer 2

450 to 750 sgft

Question 3

How many square feet can one ton of A.C. cool in Michigan?

Answer 3

700 to 1000 sqft

Question 4

Oversized distribution ductwork is a common problem with central A.C. T/F

Answer 4

False

Question 5

An undersized AC is better than an oversized one. T/F

Answer 5

True

Question 6

The typical temperature drop from outdoors to indoors with a properly operating AC system would be about 15 degrees F. T/F

Answer 6

True

Question 7

What kind of temperature drop would you expect to find in the house air as it passes over the evaporator coil?

Answer 7

15-20 degrees F

Question 8

A compressor can be thought of as a pump. T/F

Answer 8

True

Question 9

Compressors are typically located indoors on an air-to-air split system AC system. T/F

Answer 9

False

Question 10

What is the function of a sump or crankcase heater?

Answer 10

It keeps the oil at the base of the compressor warm enough to boil off the refrigerant

Question 11

List 8 common compressor problems:

Answer 11

excessive noise/vibration, short cycling/running continuously, out of level, wrong fuse or breaker size, electric wires too small, missing electrical shut off, inoperative, inadequate cooling

Question 12

The condenser coil in a split system is typically located_.

Answer 12

outdoors

Question 13

The evaporator coil in a split system is typically located _.

Answer 13

indoors (above furnace)

Question 14

The condenser fan in a split system is located __.

Answer 14

outdoors

Question 15

List 4 condenser problems

Answer 15

dirty, damaged or leaking, corrosion, dryer or water heater exhaust too close

Question 16

List 3 common configurations of evaporator coils.

Answer 16

A-coil, slab coil, vertical coil

Question 17

Evaporator coils should be upstream of furnace heat exchangers. T/F

Answer 17

False

Question 18

List 6 common evaporator problems:

Answer 18

no access to coil, dirty, frost, top evaporator dry, corrosion, damage

Question 19

In 1 sentence, describe the function of a capillary tube

Answer 19

The capillary tube acts as an obstruction in the line, reducing the pressure and temperature of the liquid refrigerant

Question 20

In one sentence, describe the function of a thermostatic valve.

Answer 20

A TXV, or TEV acts as a more precise expansion device on larger AC or heat pumps.

Question 21

List 4 common expansion device problems

Answer 21

capillary tube defects, thermostatic expansion valve connections loose, clogged orifice, expansion valve sticking

Question 22

List 5 possible causes of leaking condensate drain pans.

Answer 22

1. pan cracked or open seam
2. opening to drain line may be obstructed
3. drain line may be missing or disconnected
4. pan may not be sloped properly, allowing water to overflow rather than run to the drain
5. pan may be rusted through
6. pan may not be properly located below the coil
7. pan may be filled with debris, restricting the amount of water it can hold

Question 23

When is an auxiliary condensate drain pan needed?

Answer 23

auxiliary pan is needed when the evaporator coil is located in attic, or anywhere over a finished living space.

Question 24

What are condensate drain lines usually made of?

Answer 24

plastic or copper

Question 25

Do condensate drain lines ever have a trap?

Answer 25

condensate line from the primary pan may or may not have a trap. Lines from secondary pans should never be trapped.

Question 26

If condensate drain lines have a trap, what is its purpose?

Answer 26

1. trap may be required if the condensate pan is upstream of the house air fan, b/c the water is under negative pressure. 2. if the condensate is allowed directly into waste plumbing, a trap is required.

Question 27

List 2 acceptable discharge points for condensate drain lines and one generally unacceptable discharge point.

Answer 27

acceptable: outside the building directly into the ground, near the basement floor drain unacceptable: into the granular fill beneath the basement floor slab, into the waste plumbing stack

Question 28

List 3 common condensate pump problems

Answer 28

inoperative, leaking, poor wiring

Question 29

Refrigerant lines are usually made of:

Answer 29

copper

Question 30

The larger refrigerant line contains a liquid. t/F

Answer 30

False

Question 31

The smaller refrigerant line is called the suction line. T/F

Answer 31

False

Question 32

The larger refrigerant line is called the return line. T/F

Answer 32

True

Question 33

List 5 common refrigerant line problems:

Answer 33

1. leaking 2. damage 3. missing insulation 4. lines too warm or cold 5. lines touching each other

Question 34

How would you normally identify a leak in a refrigerant line visually?

Answer 34

This may be identified by an oil residue below the line set, typically at valves or coil connection

Question 35

Which line should be cold when the system is operating?

Answer 35

suction line

Question 36

Which line should be warm when the system is operating?

Answer 36

liquid line

Question 37

Which refrigerant line should be insulated?

Answer 37

suction line

Question 38

Where is the condenser fan in a split system?

Answer 38

outside in the condenser unit

Question 39

What is the typical inlet & outlet temperature of air across the condenser fan?

Answer 39

inlet temperature is outdoor air temperature, & outlet temperature is roughly 15 to 20 degrees F higher than the outdoor temperature

Question 40

List 4 common condenser fan problems.

Answer 40

excessive noise/vibration, inoperative, corrosion or mechanical damage, obstructed air flow

Question 41

Where is the evaporator fan typically located in a split system.

Answer 41

Indoors

Question 42

The amount of air that must cross an evaporator coil in a heating climate is less than the amount of air that must cross a conventional furnace heat exchanger coil. T/F

Answer 42

False

Question 43

Oversized ducts are a common problem. T/F

Answer 43

False

Question 44

High level returns are more appropriate for heating and cooling. T/F

Answer 44

False

Question 45

Ducts passing through unconditioned spaces such as attics or crawlspaces should be___.

Answer 45

Insulated, with appropriate vapor barriers

Question 46

List 7 common problems with thermostats.

Answer 46

1. Inoperative 2. poor location 3. not level 4. loose 5. dirty 6. damaged 7. poor adjustment/calibration

Question 47

How long do AC compressors typically last in your area?

Answer 47

1. 8 to 10 years-southern USA 2. 10 to 15 years-moderate climates 3. 15 to 20 years-northern climates

Question 48

What is the typical warranty period for a compressor?

Answer 48

5 years typically

Question 49

Heat pumps are generally sized based on the: a. heating load b. cooling load c. other

Answer 49

cooling load

Question 50

The implication of an oversized heat pump during summer months is:

Answer 50

It would cool the house down too fast without dehumidifying the air, resulting in a cool, damp environment

Question 51

You should not operate the heat pump in the heating mode when the outdoor temperature is above __

Answer 51

65 degrees F

Question 52

You should not operate the heat pump in the cooling mode when the outdoor temperature is below__

Answer 52

65 degrees F

Question 53

List at least 8 clues that would suggest that you are looking at a heat pump rather than a central AC system.

Answer 53

1. data plate may say "HP" or Heat Pump 2. Thermostat has an emergency heat setting 3. both refrigerant lines are insulated 4. presence of a reversing valve 5. compressor is indoors & its 's an air-to-air system 6. presence of an outdoor thermostat connected to control wiring 7. If it is winter & the unit is operating, it's a heat pump 8. You find a two-stage thermostat 9. You find 2 expansion devices