Refrigeration systems are designed for what two substances to circulate in them?
Refrigeration and oil
To pull a vacuum means to ....?
Lower the pressure in a refrigeration system.
Are noncondensible gases desirable in a refrigeration system?
No
A mercury U-tube manometer
Is used to measure atmospheric pressure.
A micron gauge...
Is often used to measure a vacuum at less than 1mm Hg
How many microns are in 1mm Hg?
1,000
A multiple evacuation means that...?
You pull a vacuum on a refrigeration system more than once, allowing some refrigerant back into the system between each procedure.
If a vacuum has been pulled on a system and there is a leak, the vacuum gauge will...?
Begin to rise
Moisture in a liquid state must be __________ before it can be removed with a vacuum pump.
Vaporized
1 in Hg equals
25,400 microns
What can a cold trap be used for?
To protect the vacuum pump when excess moisture is in a system to be evacuated.
The deep vacuum method reduces pressure in the system to about....?
250-500 microns
What is the most common and most accurate vacuum gauge?
Digital micron gauge
Water makes a large volume of vapor when boiled at low pressure levels. If possible, it should be drained from a system as a ________?
Liquid.
What is Evacuation?
Degassing and dehydrating a system.
It is not required by the EPA to repair systems that contain less than ______ lb of refrigerant. For industrial processes equipment and commercial refrigeration equipment, systems that contain more than ______ lb of refrigerant must be repaired when the l
50,50,35,15
What are the six classes of leaks?
Standing leaks, pressure dependent leaks, temperature dependent leaks, vibration dependent leaks, combination dependent leaks, and cumulative microleaks.