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R-22 is a high-pressure refrigerant; therefore, type II certification is needed. R-11 and R-123 are low-pressure refrigerants.
The standard for machine room safety is ____.
What should be done after recovering liquid refrigerant from refrigeration system?
Recover the vapour refrigerant
EPA regulations require that any appliances containing more than 50 pounds of refrigerant, except for commercial and industrial process refrigeration, must be repaired when the leak-rate exceeds ______ of the charge per year.
In which part of low pressure refrigeration system may the leaks occur?
Gaskets & Fittings
What is the purpose of rupture disks in low pressure chillers?
To relieve the pressure
A partial charge low pressure system can be effectively leak checked by _______
Increasing refrigerant pressure by adding external heat source.
In a low pressure refrigeration system, the rupture disk is connected to _______
What can a technician do to prevent trapped water freezing, which is caused by using a large vacuum pump?
He should increase the system pressure by introducing nitrogen gas.
What type of equipment can be worked on with Type III certification?
In a low pressure system, if the maximum pressure setting exceeds during leak checking, it will _______
Cause a rupture failure
According to ASHRAE Guideline 3-1996, if the pressure in a system rises from 1 mm Hg to a level above ______ during a standing vacuum test, the system should be checked for leaks.
2.5 mm Hg
To obtain an accurate vacuum readings during system evacuation, the system vacuum gauge should be located ______.
as far from the vacuum pump as possible.
According to the EPA, there is approximately ________ of refrigerant vapor left in an average 350 ton R-11 chiller at 0 psig pressure once all the R-11 liquid has been removed.
How much of vapor is contained in a 350 ton R-11 chillier after all the liquid has been removed?
The hydrostatic test is used to check _______ within a chiller.