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Flashcards in Split Systems Deck (93)
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1

Which gauge on the manifold gauge is considered to be the compound gauge?

The low side gauge (blue) is a compound gauge

2

Name four main types of electronic leak detectors?

Ion source detection, thermistor type, halogen type, and ultrasonic type

3

What is the difference between a recovery unit and a recycle unit?

Recycle units work in the same manner as the recovery units, but they take it one step further by adding filters and oil separators that remove any compressor oil, moisture, and some contaminants from the refrigerant

4

What is the maximum capacity of any service or storage cylinder used for refrigerant?

Must not be filled 80 percent of its capacity

5

What does reclaiming the a refrigerant mean?

It is cleaned and processed to new specifications

6

Why should nitrogen be purged through the copper lines when they are being brazed?

To prevent oxidation

7

How should we purge nitrogen through the copper lines when they are being brazed?

By allowing a small amount of nitrogen into the system at a very low pressure less than 2 psig.

8

Which hoses are connected to each service valve?

The low pressure gauge (blue gauge) goes to the low pressure side of the system. The high pressure side (red gauge) goes to the high pressure side of the system. The centre hose in connected to the inlet port on the recovery unit.

9

What color is the gauge on the low pressure gauge?

Blue

10

What color is the gauge on the high pressure gauge?

Red

11

To what pressure should the system be tested when dealing with refrigeration?

A pressure between 125 psi to 150 psi is considered safe for most systems.

12

Removing the stem in the Schraeder valve speeds up the evacuation process. True or False?

True

13

What amount of vacuum must be obtained to render the system free of refrigerant?

10" to 11" of Hg

14

What are the two reasons for performing a deep evacuation?

To remove moisture, and to remove non-condensable gases

15

When is a triple evacuation used?

If the system is deemed to be dirty or wet

16

How many CFM is required for each ton of cooling?

Between 400 CFM to 425 CFM per ton of cooling

17

What are the two methods of calculating the CFM in a system?

Calculating by temperature rise across the evaporator coil and calculating by static pressure across the evaporator coil.

18

Which ways of calculating CFM is one of the most accurate?

The static pressure method

19

Which method is used for checking the refrigeration charge on a system equipped with a TXV?

The method of checking for proper sub-cooling

20

We as sheet metal workers are allowed to service and install cooling systems up to and including?

60 000 Btuh (5 tons)

21

What are installed on all newer condensing units?

Both liquid line and suction line service valves are installed on newer units.

22

What is a manifold gauge set used for?

To diagnose and service air-conditioning and refrigeration systems properly.

23

What color is the centre hose manifold gauge usually?

Yellow

24

What are the yellow hand valves on the manifold used for?

To perform recovery, evacuation and recharging procedures.

25

What is the sight glass on the manifold used for?

It allows you to see if there is a liquid, gas bubbles, or vapour in the system.

26

What should you always do when using gauge sets that were used on different refrigerants in order to avoid cross contamination?

Purge the lines with nitrogen

27

Most copper tubing has a max pressure of?

700 PSI

28

What are three styles of gauges used in the refrigeration field?

High pressure, vacuum, and compound gauges

29

Always remember gauges should never be subjected to more than ____ of their full scale range on the gauge face.

75 percent

30

Hoses are constructed to withstand pressures in excess of?

500 psi (burst pressure 2000 psi)