UA Star Part 1.1

An unrepaired leak will cause which of the following conditions?

• high head pressure

• high subcooling

• high superheat

• low superheat

If mechanical refrigeration and a cooling coil are used dehumidification, the system may require which of the following?

• High limit control

• recooling

• reheat

• zero voltage switching

Which is the response when dirty filters in an air conditioning system reduce the quantity of air flowing over the DX coil?

• the compressor will compensate for the change

• the condenser will compensate for the change

• the system capacity will decrease

• the system capacity will increase

In an air-cooled system with capacity control, compressor unloading will cause which of the following to happen?

• discharge pressure will rise, and energy consumption will decrease

• suction pressure in discharge pressure will fall

• suction pressure will fall, and energy consumption will decrease

• suction pressure will rise, and discharge pressure will fall

Which is the only acceptable refrigerant to be used as a trace gas when checking for leaks?

• R11

• R12

• R22

• R500

After January 2019, what is the acceptable annual leak rate of a comfort cooling system if this circuit contains more than 50lbs of refrigerant?

• 10%
• 25%

• 35%

• 40%

For what purpose is a cold trap installed in a series with a vacuum pump?

• cool the vacuum pump oil

• permit a pressure below 100 microns to be developed

• reduce the rate at which water vapor is drawn into the vacuum pump's oil

• reduce the systems deep vacuum requirement

When recovering “bad” R-12 and R-22, how or where should it be stored?

• a used disposable cylinder

• an ARI 700 cylinder

• an ISO guideline cylinder

• an ARI 720 cylinder

What is cleaning refrigerants to ARI 700 standards called?

• reclaiming

• recovering

• recycling

• reuse

How often should the oil in a vacuum pump be changed?

• after 100 hours or when oil starts to bubble

• after the vacuum pump can no longer achieve desired vacuum level

• annually

• the oil should only be changed when it is no longer clear