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? - A
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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.
A deep vacuum is usually measured in? - Answer- Microns.
Heat Pumps that use R-134A should be leak checked with? - Answer- Pressurized Nitrogen.
During the evacuation of a system that contains large amounts of moisture it may be necessary to increase pressure in the system with ________, to counteract the freezing of the moisture. - Answer- Nitrogen.
When under a deep vacuum, the motor winding of a hermetic refrigeration compressor? - Answer- Will be damaged if energized.
When using recovery or recycling equipment that was manufactured AFTER November 15, 1993: you must evacuate a system containing MORE than 200 pounds of CFC-12 to _______ before making a major repair. - Answer- 15 inches Hg vacuum
When inspecting a system for leaks, you should look for? - Answer- Traces of oil.
Refrigerant leaves the receiver of a system as a? - Answer- High pressure liquid.
A compressor heater is used to? - Answer- Reduce the amount of refrigerant in the lubricating oil.
The evaporation temperature of R-134a at 0 psig is? - Answer- -15F
Dry nitrogen should be used to break the first vacuum when dehydrating by the double evacuation method. However, it? - Answer- Can be dangerous if not used with a pressure regulator.
When servicing a 60-ton packaged rooftop unit. The easiest way to check the type of refrigerant is uses is to? - Answer- Look at the unit nameplate.
R-410A requires certified recovery & recycling machines rated for at least? - Answer-
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