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Flashcards in EPA Type 2 Deck (48)
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1
Q

What conditions allow for a system to be opened and repaired without recovering the refrigerant to the required vacuum level

A

A system with a large leak and system pressure of atmospheric

2
Q

High pressure appliances can be evacuated to atmospheric pressure when

A

Leaks make evacuation to the prescribed level unattainable

3
Q

EPA regulations state that maintenance, service, or repair involving the removal of the following components is major repair

A

Compressor, condenser, evaporator, auxiliary heat exchanger coil

4
Q

Refrigerant should be removed from the condenser outlet if the condenser is

A

Below the receiver

5
Q

When EPA regulations change regarding refrigerant usage

A

Technician can lose their certification or be fined if violating updated regulations even if unaware of changes

6
Q

If a refrigeration condensing unit is sittin idle in an ambient temperature of 86*F at a pressure of 93psig it must contain

A

R-12

7
Q

A crankcase heater is often used to prevent refrigerant from migrating to the oil during periods of

A

Low ambient temperature

8
Q

Recovering refrigerant from the discharge service valve if a compressor is known as

A

The pull method of recovery

9
Q

What might be an indication of a loss of charge in a fixed orifice A/C system

A

Increased evaporator superheat

10
Q

What is the smallest size leak which EPA regulations say must be repaired on an air cooled chiller servicing the A/C in an office building and containing a charge of 240lbs of r-22

A

3lbs per month

11
Q

High pressure appliances containing 100lbs of an hcfc other than r-22. Recover and recycling equipment manufactured after Nov. 15, 93 must be evacuated to a level of

A

10” hg

12
Q

An r22 evaporator operating at a pressure of 83psia and with a suction line leaving it at 52F is operating with __ if superheat

A

12 degrees

13
Q

EPA regulations require that all commercial and industrial process refrigeration containing more than 50lbs of refrigerant must be repaired when the annual leak rate exceeds

A

35%

14
Q

R22 unit containing 255lbs by weight of refrigerant charge is recovered down to 15” hg and after five minutes the pressure rises and levels off at 10” hg then

A

Recovery is complete

15
Q

Which of the following refrigerants is an hcfc

A

R22

16
Q

A systems compressor should never be __ when in a deep vacuum

A

Energized

17
Q

When replacing the compressor on a 50 ton system which contains a receiver, the charge can be

A

Pumped into the receiver for storage during service

18
Q

When brazing in refrigeration system accessories which use neoprene or rubber gaskets

A

Wrap a wet rag around the area to keep it cool

19
Q

For the fastest recovery of a system which should be recovered first

A

Liquid refrigerant from the receiver

20
Q

Unless plans are made to replace a system exceeding the max leak, repairs must be made in

A

30 days

21
Q

Non condensables will cause

A

Higher discharge pressures

22
Q

An overcharged system will operate

A

Less efficiently

23
Q

Which refrigerant is considered high or very high pressure refrigerant

A

Hfc134a

24
Q

What would be most thorough for leak testing

A

Mixture of trace r22 with nitrogen backed up to 300psig

25
Q

When using nitrogen to pressurize a system for leak testing always make sure to use

A

A regulator on the nitrogen tank

26
Q

What should one do to an empty A/C system after repairing a leak and before recharging it

A

Check the system for leaks

27
Q

A refrigeration system which has a txv will likely be __if it has 2*F of sun cooling in the liquid line, just after the condenser

A

Undercharged

28
Q

At which location is a low loss fitting on your manifold hose likely to prevent the most venting of refrigerant

A

At the king valve

29
Q

The purpose of a vacuum pump is to

A

Remove air and moisture from a system before charging it with refrigerant

30
Q

A/C system short cycling is normally caused by

A

The system being oversized for the home

31
Q

Proper recovery techniques begin with the use of appropriate recovery equipment that has been certified by

A

EPA approved equipment testing organization

32
Q

When dehydrating a system it should be evacuated to a level of

A

500 microns

33
Q

Recovering r500 from an A/C system containing 12lbs of charge, the unit must be recovered down to a pressure of

A

10” hg

34
Q

The purpose of a purge or pump out mode of a recovery machine is to

A

Help clear another refrigerant from the machine in order to avoid mixing refrigerants

35
Q

What can help reduce the time necessary to recover the refrigerant from a unit (3things)

A

Shorter hoses, cool the recovery cylinder, run the unit to warm it

36
Q

All refrigeration and HVAC systems are protected by a

A

Pressure relief valve

37
Q

According to EPA regulations, the refrigerant in a system containing 12lbs of refrigerant and an inoperative compressor can

A

Legally be recovered using passive methods

38
Q

How much refrigerant must leak out of a 2ton residential A/C system before EPA regulations require that the leak be fixed

A

Not required to be leak free

39
Q

If pulling a system down to the EPA required recovery level cannot be accomplished because of system leaks

A

It must be recovered down to at least 0psig

40
Q

What can be done with the refrigerant trace gas and nitrogen after the leak is found

A

Can be released to the atmosphere

41
Q

A refrigerant sensor which will sound an alarm and automatically start a ventilation system in occupied equipment rooms falls under

A

ASHRAE standard 15

42
Q

A new split system should be checked for leaks by

A

Pressurizing the system with r22 and an inert gas

43
Q

When recovering from a system with a refrigerant leak, recover to a level of

A

0 psig

44
Q

What happens to a refrigerant that is above the saturation temperature

A

It remains in a vapor state

45
Q

When using a recovery system manufactured after Nov. 15, 93 on a system containing 100lbs of r502 must be evacuated to

A

10” hg

46
Q

Industrial and process refrigeration units with a 50lb charge or more with an annual leak rate of __ or more must have leaks repaired

A

35%

47
Q

Refrigerants cfc r12, hcfc r22 and hfc 134a are classified as

A

A1

48
Q

A high pressure appliance containing 210lbs of refrigerant recovery and recycling equipment manufactured before Nov. 15, 93 must be evacuated to a level of

A

4” hg