Summary: PPT

Question 1

1. Heat pumps can pump heat two ways to provide both heating and _____
2. Four-way ______ valves control the direction of flow of heat-laden vapour between the low- and high-pressure sides of the system

Answer 1

1. cooling

2. reversing

Question 2

1. In cooling mode, the outdoor coil functions as the ______ and the indoor coil functions as the _______
2. In the heating mode, the outdoor coil functions as the ______ and the indoor coil as the ________

Answer 2

1. condenser, evaporator

2. evaporator, condenser

Question 3

1. Metering devices are located at the inlet of both the ______ and ______ coils
2. Check valves are used to _____ the metering device that should not be in the active refrigerant circuit
3. bidirectional or bi-flow filter driers are ___ driers in a single shell and are designed for heat pump applications

Answer 3

1. indoor and outdoor
2. bypass
3. two

Question 4

1. In the heating mode, heat pumps lose ______ as the outside ambient temperature drops
2. _______ heat is required when the heat pump cannot provide all the heat that a structure needs

Answer 4

1. efficiency

2. auxiliary

Question 5

1. Balance point occurs when the heat pump can pump in exactly as much heat as the structure is ______ out
2. coefficient of performance (COP) is the ratio of usable heat (in watts) produced from each watt of energy purchased

Answer 5

1. leaking

Question 6

1. In winter operation, the ___ increases as the outside ambient temperature increases
2. Split heat pump systems require the installation of gas and liquid lines to connect the indoor and outdoor units
3. the indoor unit contains the fan and coil and often the ______ ____ heaters

Answer 6

1. COP

3. electric strip

Question 7

1. Maximum air supply temperatures are around ___F
2. Outdoor coil should be installed so it is raised above the ground pad to allow ______ water to run to the ground
3. A defrost system is provided to defrost ice from the ___
4. outdoor ___ turns off during defrost and system is put into ____ mode in order to run hot gas at outdoor coil to melt ice. It is more efficient to have the fan off as it is better ____ transfer

Answer 7

1. 100F
2. defrost
3. coil
4. fan, cool, heat

Question 8

1. Package heat pump systems have all system and electrical components in ___ housing
2. There are two heating systems and ___ cooling system
3. Auxiliary heating system must be operated as a system by itself in case the heat pump _____

Answer 8

1. one
2. one
3. fails

Question 9

1. Automatic changeover thermostat changes automatically between _____ and _____ modes
2. _______ heat mode is used in the event of heat pump failure
3. The need for defrost varies depending on ______ air temperatures and conditions

Answer 9

1. heating and cooling
2. emergency
3. outside

Question 10

1. The more moisture in the air, the more frost that forms on the outdoor ____
2. Defrost affects _______ of the systems
3. Air-to-Air heat pumps accomplish defrost by stopping the ______ fan and cycling unit into ______ mode

Answer 10

1. coil
2. efficiency
3. outdoor, cooling

Question 11

1. Combinations of ____, ______, and _____ drop across the outdoor coil are also used in some systems to determine when defrost is needed and when defrost is terminated
2. Defrost can also be controlled ________

Answer 11

1. time, temperature, and pressure

2. electronically

Question 12

1. In a heat pump, the ___ must be started at the beginning of each mode of operation
2. the _____ fan motor often operates during defrost
3. During the cooling mode, system is operating as a ____-temperature refrigeration system

Answer 12

1. fan
2. indoor
3. high

Question 13

1. During the heating mode, system is operating as a ___-temperature refrigeration system
2. Common reversing valve problems include: ____ valve, defective coil and internal _____

Answer 13

1. low-temperature

2. stuck valve, leaks

Question 14

1. _________ readings of the reversing valve connections can be taken to evaluate the valve
2. Most heat pumps are ________ charged systems
3. If the system operated correctly in at least one mode, the refrigerant charge is _____

Answer 14

1. temperature
2. critical
3. correct

Question 15

1. Oil or gas furnaces can be used for ________ heat
2. The heat pump coil must be installed downstream of the oil or gas heat _______
3. scroll compressor is ideally suited for heat pump applications because of its pumping __________

Answer 15

1. auxiliary
2. exchangers
3. charcteristics

Question 16

1. Scroll compressors normally do not require a suction-line accumulator because they are not as sensitive to liquid _______
2. Use of variable speed motors for the compressor and both fan motors is the method used to improve system ______ in heat pump systems

Answer 16

1. flood back

2. efficiency