Gauges And Vacuum Pumps

Question 1

O2 cylinders are charged at:

Answer 1

2200psi at 70*F

Question 2

Moisture in a system causes:

Answer 2

Ice, rusting, corrosion, refrigerant decomposition, oil sludge and system deterioration

Question 3

Air in a system causes:

Answer 3

High head pressure and high operating temps

Question 4

Before evacuation, what needs to be done?

Answer 4

The systems internal pressure must be reduced to 0psig. Cannot start vacuum above atmosphere pressure

Question 5

0 psig or 14.7 psi = xx microns

Answer 5

760,209.4 microns

Question 6

Factors to how much time it takes to pull a vacuum

Answer 6

Size of system
Amount of moisture in system
Capacity of vacuum pump
Condition of vacuum pump oil

Question 7

What is a deep vacuum?

Answer 7

Pulling the system down to 500 microns in one long pull.

Question 8

What is a triple Evac?

Answer 8

Pulling three vacuums and injecting nitro in between
2600microns
Nitro
1000microns
Nitro
500microns

Question 9

What is a Nitro cylinder pressurized at?

Answer 9

2350 psig

Question 10

Color code refrige cylinders:
White
Green
Yellow
Purple
Orange
Pink

Answer 10

White = R-12
Green = R-22
Yellow = R-500
Purple = R502
Orange = R-11
Pink = R410a

Question 11

Hydrostatic pressure can do what?

Answer 11

Cause an explosion if a cylinder is filled over 80%

Question 12

3 pressure relief valves found in cylinders

Answer 12

Spring-operated relief valve
Rupture disk
Fusible plug

Question 13

Passive recovery method:

Answer 13

Use with system running
The compressor us used to push the refrigerant into the cylinder

Question 14

Active recovery method:

Answer 14

Used when system is off.
Use a recovery unit to pull refrigerant out of the system and into a cylinder
Pull out liquid first.
Then pull out remaining vapor.

Question 15

What is a pump down?

Answer 15

The refrigerant is stored temporarily in one part of the system, and closed off to the rest. Ie in the compressor ir liquid receiver

Question 16

Pump down procedure:

Answer 16

Close valve at liquid receiver outlet valve
Compressor evacuates refrigerant from low side and stores it in the liquid receiver
Turn off the compressor
Close liquid receiver Inlet valve or other high side valve to isolate and contain
Leaves low side in a vacuum

Question 17

Pump down into condenser

Answer 17

Front seat pump down shut off valve
Once low side psig 0, front seat discharge service valve and shut off system