Flashcards in Split Systems Deck (93)
Which gauge on the manifold gauge is considered to be the compound gauge?
The low side gauge (blue) is a compound gauge
Name four main types of electronic leak detectors?
Ion source detection, thermistor type, halogen type, and ultrasonic type
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
What is the maximum capacity of any service or storage cylinder used for refrigerant?
Must not be filled 80 percent of its capacity
What does reclaiming the a refrigerant mean?
It is cleaned and processed to new specifications
Why should nitrogen be purged through the copper lines when they are being brazed?
To prevent oxidation
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.
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.
What color is the gauge on the low pressure gauge?
What color is the gauge on the high pressure gauge?
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.
Removing the stem in the Schraeder valve speeds up the evacuation process. True or False?
What amount of vacuum must be obtained to render the system free of refrigerant?
10" to 11" of Hg
What are the two reasons for performing a deep evacuation?
To remove moisture, and to remove non-condensable gases
When is a triple evacuation used?
If the system is deemed to be dirty or wet
How many CFM is required for each ton of cooling?
Between 400 CFM to 425 CFM per ton of cooling
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.
Which ways of calculating CFM is one of the most accurate?
The static pressure method
Which method is used for checking the refrigeration charge on a system equipped with a TXV?
The method of checking for proper sub-cooling
We as sheet metal workers are allowed to service and install cooling systems up to and including?
60 000 Btuh (5 tons)
What are installed on all newer condensing units?
Both liquid line and suction line service valves are installed on newer units.
What is a manifold gauge set used for?
To diagnose and service air-conditioning and refrigeration systems properly.
What color is the centre hose manifold gauge usually?
What are the yellow hand valves on the manifold used for?
To perform recovery, evacuation and recharging procedures.
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.
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
Most copper tubing has a max pressure of?
What are three styles of gauges used in the refrigeration field?
High pressure, vacuum, and compound gauges
Always remember gauges should never be subjected to more than ____ of their full scale range on the gauge face.