問題一覧
1
What is the state of refrigerant coming out the evaporator
Superheat vapor
2
what’s the material in a filter dryer?
Desiccant
3
what are the 3 method of heat transfer
Convention, conduction, radiation
4
what type of oil is used in HFC refrigerant
Polyester
5
what type of gauge measures above and below
compound gauge
6
At what point is refrigerant changing state
saturated
7
What is the pressure scale 14.7
PSIA
8
Amount heat it takes 1 pound of water 1 degree Fahrenheit
1 BTU
9
relative humidity
Air temperature
10
A liquid vaporizing without addition of the heat caused by a pressure drop
flashing
11
how much heat absorbed with 3 tons of cooling
36,000 BTU per hour
12
the minimum vacuum we pull
500 microns
13
what must be connected to the end of the manifold hoses
Low loss fittings
14
what side is compound gauge connected
Low side
15
when is a recovering cylinder full
80% water capacity
16
sub cooling is measures where
Liquid line
17
which device is metering device
thermostatic expansion valve
18
what is the purpose of metering device
Regulate refrigerant flow
19
what used to connect copper tubing to other devices without blazing it
Flaring
20
define recovery
to remove refrigerant and moving it to a external container
21
why do we pull a vacuum
To remove moisture and noncondensibles
22
when charging a stystem with the compresser running the refrigerant is added
Added to the low side
23
which component absorbs heat
Evaporator
24
which component rejects heat
condenser
25
what temperatures must be measured to find delta T
Return and supply
26
which of the following is type of evaporter
A-coil
27
what component of R-22 is responsible ozane depletion
chlorine
28
what is a purpose of a compressor
pump refrigerant vapor rise temperature rise pressure all of above
29
if you reduce the volume of a contain vapor will you reduce or rise lower pressure
Rise, vapor pressure
30
which system measurement is most effective by relative humidity
Delta T
31
Second law of thermodynamics
Hot goes to cold
32
cooling a liquid below saturation temperature
Subcooling
33
define refrigeration
to remove heat where its not wanted and moving it where it does not matter
34
what is the purpose of a psychrometer
Measure, wet bulb
35
what type of refrigerant will fractionate during change of state
Zeotrope
36
which gas should be use to pressure test
nitrogen
37
metering device is located
at the inlet of evaporator
38
purpose of fiter dryer
Removes debris and dehydrate
39
2 methods of recovery
self-contained and system dependent
40
how many Cfm per ton minimum
400 CFM
41
what’s the name of the line that carry superheat vapor from now evaporator to the compressor
suction line
42
what is the specific heat of ice
0.5 BTU