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100
On a high pressure system, ______________ is an indicator of a possible leak.
What is excessive superheat.
100
Heat Pumps that have been retrofitted from R-22 to R-407 should be leak check with
What is pressurized nitrogen
100
The EPA regulations require that leaking commercial or industrial process refrigeration equipment must be repaired when the leak rate exceeds what percent of the charge per year?
What is 35%
100
The recovery rate can be increased by
packing the recovery vessel in ice
100
Recovered refrigerant may contain:
acids, moisture and oils.
200
R-410A requires a high pressure manifold gauge and hose set that must have
4000 psig burst pressure and 800 psig working pressure
200
Before using a recovery unit to remove a charge, what steps should be taken?
check service valve positions, oil level in the recovery unit and evacuate the recovery unit and tank.
200
R-410A requires certified recovery and recycling machines rated for at least how many psig?
400 psig
200
Which repair would ALWAYS be considered "major" under EPA's regulations? a) Replacement of an evaporator coil. b) Replacement of a filter drier. c) Replacement of a schraeder valve core. d) Replacement of a condenser fan motor.
a) Replacement of an evaporator coil.
200
System-dependent recovery equipment cannot be used when
the appliance contains over 15 pounds of refrigerant
300
A system can be evacuated to only atmospheric pressure when
leaks in the appliance make proper evacuation unattainable.
300
When servicing a 60-ton packaged rooftop unit, the easiest way to check the type of refrigerant it uses is to: _________. a) use your service gauge set and a refrigerant card b) ask the owner c) look at the unit nameplate d) determine the condenser size
c) look at the unit nameplate
300
A deep vacuum is usually measured in: _______.
microns
300
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?
recover as much of the R-502 from the recovery unit as possible, change filter, and evacuate
300
Use _________ to remove ice from a sight glass.
an alcohol spray
400
The refrigerant pressure inside an R-12 unit which is at room temperature 72F and not operating is how many psig
approximately 74
400
For what refrigerants is an equipment room refrigerant monitor required under ASHRAE Standard 15
R-123
400
The vacuum pump used to evacuate a system should be capable of pulling a vacuum of
500 microns
400
Never use oxygen or compressed air to leak-check hardware because R-410A can: _________.
explode when mixed with air or oxygen
400
The fastest way to recover refrigerant from a system is to remove it in the _______ phase? a) final b) initial c) liquid d) vapor
Liquid
500
When using recovery and recycling equipment manufactured BEFORE November 15, 1993 technicians must evacuate a unit that has a normal charge of 10 pounds of CFC-500 to _______ before disposing of the system.
4 inches of Hg vacuum
500
Which statement is NOT true about recycling and recovery equipment manufactured after November 15, 1993? a) It must be tested by an EPA-approved third party. b) It must meet vacuum standards more stringent than those met by equipment manufactured before November 15, 1993. c) It must be equipped with low-loss fittings. d) It must have an oil separator.
It must have an oil separator.
500
A reciprocating compressor should not be energized when the discharge service valve is
closed
500
When servicing an operating unit that has a receiver/storage tank the refrigerant should be
recovered into the receiver.