AND ANSWERS
When a new system has been assembled, the first thing to do is? - Answer-Pressurize
the system with an inert gas & leak check.
After installation of a field-piped R-410A split heat pulp, the unit should first be? -
Answer-Pressurized with nitrogen then leak checked.
The EPA regulations require that any appliances containing more than 50 pounds of
refrigerant (except for commercial & industrial process refrigeration) must be repaired
when the leak rate exceeds _________ of the charge per year? - Answer-15%
R-410A requires recovery tanks rated for at least? - Answer-400 psig
After refrigerant liquid has been recovered from a system, any remaining vapor is? -
Answer-Condensed by the recovery system.
Your recovery/recycling machine has R-502 refrigerant in it. You now have to recover
refrigerant from a unit with R-22. What must be done before the R-22 refrigerant can be
recovered/recycled? - Answer-Recover as much R-502 from the recovery unit as
possible, change filter, & evacuate.
In a refrigeration system with a TXV (or other type of throttling device), the component
directly following the condenser is the? - Answer-Receiver
When charging an R-410A system that uses a water-cooled condenser, you must first
charge with vapor to a pressure of at least________, before switching to liquid charging.
- Answer-120 psig
Recovered refrigerant may contain what? - Answer-1.) Acids
2.) Moisture
3.) Oils
Your recovery/recycling machine has R-22 refrigerant in it. You now have to recover
refrigerant from a unit with R-410A. What must be done before your recovery unit can
be used to recover R-410A? - Answer-1.) The recovery unit must be EPA certified for
use with R-410A.
2.) The recovery tank must be designed for the pressure of R-410A.
, 3.) The filter & lubricant in the recovery unit must be changed, & the recovery unit
evacuated.
To recover liquid refrigerant, you must connect one hose to the? - Answer-Liquid Line.
The proper charging method for blended (non-azeotropic) refrigerants (400 Series) is to
use a remove the charge from the cylinder as a? - Answer-Liquid
Before using a recovery unit to remove a charge, what steps should be taken? -
Answer-1.) Check service valve positions.
2.) Check the oil level in the recovery unit.
3.) Evacuate recovery unit & recovery tank.
On refrigeration units that use an open compressor; the ________ is most likely to leak
if the unit is not used for several months. - Answer-The rotating shaft seal.
Noncondensables in a system cause? - Answer-Higher discharge pressure.
Heat Pumps that use R-410A should be leak checked with? - Answer-Pressurized
Nitrogen.
A reciprocating compressor should not be energized when? - Answer-The discharge
service valve is closed.
In a refrigeration system, the component directly following the evaporator is the? -
Answer-Accumulator.
Manifold gauge set hoses should have self-sealing connectors or hand valves to? -
Answer-Minimize the release of refrigerant when the hoses are connected &
disconnected.
The EPA regulations require that leaking commercial or industrial process refrigeration
equipment must be repaired when the leak rate exceeds _____ of the charge per year. -
Answer-35%
Moisture is removed from a system by? - Answer-Using a filter drier.
Oil foaming usually occurs in the? - Answer-Compressor
R-410A is different from other ASHRAE 400 series non-azeotropic blends because? -
Answer-R-410A behaves as a near azeotropic refrigerant, & can be topped off.
With an air-cooled condenser on the roof of a building & the evaporator on the first floor,
recovery should first occur? - Answer-From the liquid line entering the evaporator.