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HVAC

Module 4

term
Two refrigerants exempted from the EPA requirements to recover, recycle, and reclaim are ammonia and carbon dioxide.
HCFC-22 is the only EPA-approved refrigerant that can be used for leak testing.
A safe leak testing pressure is typically 125 psig.
A typical Nitrogen cylinder is charged to a pressure of roughly 2000 psig.
An apprentice in training is exempt from the technician certification requirement for a period of two years from the date the apprenticeship was initially registered.
For the most serious violations of the Clean Air Act, the EPA will prosecute the case in federal court.
When using a self-contained recovery unit to recover refrigerant vapor, the discharge of the recovery unit is typically connected to a recovery cylinder.
If the system being recovered contains 7 pounds of refrigerant the push-pull method of recovery is typically prevented.
Moisture in the system reacts with refrigerant to form acids.
After pumping down a wet system immediately change the oil in the vacuum pump.
A vacuum pump with a capacity of six to twelve cfm should be adequate to evacuate systems with capacities up to 30 tons.
How many microns is a perfect vacuum? Zero
When the vacuum gauge shows a pressure rise that continues up to 0 psig when the pump is isolated this typically indicates a refrigerant circuit has a leak.
Near-azeotrope refrigerants are technically zeotropes.
You should always charge with liquid refrigerant from the cylinder when charging a system that uses a zeotrope refrigerant.
The range of temperatures with-in which a zeotropic refrigerant changes state at a given pressure is known as its temperature glide.
Checking the cylinder labeling is the best way to tell if a disposable refrigerant cylinder is equipped with a dip tube.
A technician should use a refrigerant scale to weigh charged refrigerant on every occasion, regardless of the method used.
Charging by super-heat is performed on systems that use a fixed-orifice metering device.
Systems with TXV can not be charged accurately using the super-heat method.
Created by: rosi_23
 

 



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