Nate Heat Pumps

Question 1

Heat can neither be _____ or _______.

Answer 1

created, destroyed

Question 2

Heat moves from _____ to _____.

Answer 2

hot, cold

Question 3

Boiling point of a substance is proportionall related to the ______ it is under. The higher the pressure, the higher the ____ _____.

Answer 3

pressure, boiling point

Question 4

suction pressure is also called low pressure and______ ____

Answer 4

back pressure.

Question 5

5 compressors used in hvac are

Answer 5

1- scroll
2- reciprocating
3- screw
4- rotary
5- centrifugal

Question 6

compressor with fewest moving parts made in the late 1980s. Compresses vapor volume into smaller and smaller area.

Answer 6

scroll: orbiting scroll moves and fixed scroll doesnt move.

Question 7

which compressor are not designed to handle liquid refrigerant.

Answer 7

scroll and recipricating

Question 8

In a single phase motor an overload is either internal between the _____ and common windings. overload can also be on the same motor externally mounted.

Answer 8

start, run

Question 9

Never take resistance reading directly on compressor terminals. Always use _____ ______ instead. Safety precaution.

Answer 9

wire leads.

Question 10

If reading an open circuit between c and windings always _____, connections are ____and _____ hasnt burned off. Check continuity of the wires as well

Answer 10

visual inspection of terminals, tight, common wire

Question 11

Causes of an open internal overload are

Answer 11

• low refrigerant/ ineffient cooling of the compressor.
• excessive refrigerant charge/ too much load/ amps/heat.
• non condensables/ air in the superheated gas in suction line and discharge line causing no refrigerant cooling of compressor.
• excessive air flow can cuase too much superheat, in efficient cooling of compressor.
• low/no airflow at condenser/ no subcooled refrigerant at metering device/ excessive super heat, no cooling of compressor.
• failing/failed capacitor.

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Question 12

line wire must be sized by guage and length to handle ______

Answer 12

minimum circuit ampacity

Question 13

Make sure the _______ panel is the proper sized to handle all _____ within the structure.

Answer 13

breaker, loads

Question 14

If there are complaints of dimming lights check all wire _______ are clean and _____ between the breaker to the compressor terminals.

Answer 14

connections, tight.