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Term

Definition

type I technician

person who maintain, service or repair small appliances

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type II technican

dispose of high or very high pressure appliances.

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type III technican

dispose of low pressure appliances.

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universal technican

repair both low & high pressure equipment & small appliances.

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the compound gauge is

blue & measures low pressure (psi) & vacuum (inches hg.)

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the high pressure gauge is

red & measures high side (discharge) pressure

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the manifold is also eqpt. with

center ports, (usually yellow hose) connected to a recovery device

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epa regulations require the hoses be equpt with

low loss fittings that will minimize refrigerant loss when hoses are disconnected.

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a Ozone molecule consist of

three oxygen atoms

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Ozone protects us from harmful

ultraviolet radiation & helps maintain stable temperatures

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depletion of Ozone in the stratosphere causes

crop loss, increase in eye diseases, skin cancer, reduce marine life, deforestation, increased ground level Ozone

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CFC'S & HCFC'S

deplete the Ozone layer

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a single chlorine atom can destroy

100,000 Ozone molecules

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chlorine in CFC's will neither dissolve in water nor

break down into compounds that dissolve in water,so they don't rain out of the atmosphere

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Ozone depletion potential is a measurement of CFC's &

HCFC's ability to destroy ozone

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HFC's (r-134a) don't contain chlorine & have no?

ozone depletion potential

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R-11, R-12,500 are?

CFCs = chlorine fluorine carbon

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R-22,123 are?

hydrogen, chlorine fluorine carbon

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R-134a is a?

hydrogen fluorine carbon

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after Nov. 14, 1994

certified required to purchase CFC & HCFC & small appl tech must be certified

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after Nov. 15, 1993

refrigerant recovery & or recycling eqpt. must be certified & labeled by an EPA & you must evacuate to 10' prior to major maint. for 40 pd. system

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since Nov. 15, 1995

violation to vent HFC's

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since July 1, 1992

violation to vent CFC's or HCFC's

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Dec. 31, 1995

CFC's were phased out of production

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violation to dispose of a disposable cylinder with out first

recovering any remaining refrigerant (to 0 psig) & then rending the cylinder useless. then recycling the metal

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violation to fail to recover CFC's, HCFC's,or HFC before

opening or disposing of an appliance

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violation to fail to have an EPA approved recovery device, equipped with

low loss fittings, & register the device with the EPA

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violation to add nitrogen to a fully charged system, for the purpose of leak detection, and thereby cause

a release of the mixture

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to recover is to

remove refrigerant in any condition from a system & store it in an external container

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to recycle is to

clean refrigerant for reuse by separating the oil from the refrigerant & removing moisture from the refrigeratn by passing it through one or more filter driers

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to reclaim is to

process refrigerant to a level equal to new (virgin) product spec as determined by chem analysis.

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reclaimed refrigerants must meet the standard set forth in

ARI 700 before it can be resold

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system dependent

captures refrigerant with the assist of component in the appliance from which refrigerant is being recovered

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self contained

has it's own means to draw the refrigerant out of the appliance

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R-134a is a HFC & is considered

ozone friendly, will not mix with most refrigerant oils,when leak testing an R-134a system to use pressurized nitrogen, R-134a refrigerant systems are ESTERS.

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ternary which means

a three part blend, are used with a synthetic alkylbenzene lubricant

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most refrigerant oils are

hygroscopic, have a high affinity for water.

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temperature glide refers to a refrigerant blend that has

a range of boiling points or condensing points through out the evaporator & condenser respectively

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azeotropic blend

mixture that acts like a single component refrigerant over it's entire temp/pressure range, doesn't have a temp glide

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ti is important not to mix different refrigerant in the same recovery tank because

the mixture may be impossible to reclaim. recover only one type of refrigerant into a recovery cylinder.

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if a strong odor is detected during the recovery process what happen

a compressor burn out has likely occurred, watch for signs of contamination in the oil

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a suction line filter drier should be installed to

trap any debris that may damage the new compressor

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long hoses will cause pressure drop, and

increase recovery time, & have a potential for increased emission

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the lower the ambient temp the

slower the recovery rate

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use an electronic or ultrasonic leak detector to

determine the general area on a leake

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reason for dehydrating a refrigeration system is to

remove water & water vapor,

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if moisture is allowed to remain in an operating refrigeration system what will occur

hydrochloric & hydrofluoric acids may form

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never evacute a system to ambient air with out first

following proper recovery procedures & attaining the mandated vacuum level

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Recovery cylinders are designed to be refilled & have

2 ports, one liquid & one vapor

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Recovery cylinders are not to be over filled above _______ or heat these cylinders may cause _______

80%, An explosion

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Refillable cylinder must be hydrostatically tested and

date stamped every 5 yrs

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Refillable cylinders used for transporting recovered pressurized refrigerant must be

DOT approved

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Approved refrigerant recovery colors are

Yellow top & gray bodies

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When pressurizing a system with nitrogen, you should always

Charge thru a pressure regulator & insert a relief value in the downstream line from the pressure regulator.

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Relief values must not be

Installed in series, replaced if corrosion build up is found.

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When leak checking a system never pressurize the system with

Oxygen or compressed air, can cause an explosion.

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To determine the safe pressure for leak testing,check

The data plate for the low side test pressure value

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Schrader values, it's critical to inspect for

Core for leaks,bends & breakage, replace & always cap ports to prevent accidental depression.

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Never heat a refrigerant cylinder with

An open flame,don't cut or braze refrigerant line unit.

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SCABA is required for

Large release of refrigerant in a confined area, if SCBA isn't available, vacate & ventilate the area.

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Inhaling refrigerant vapors or mist may cause

Heart irregularities, unconsciousness, & oxygen deprivation leading to death (asphyxia)

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Never expose R-22 or R-12 to open flames orrr glowing hot metal surfaces

At high temperature, R-12 & R-22 decompose to form Hydrochloric acid,Hydrofluoric acid, & Phosgene gas.

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Recovery eqpt. Manufactured Before Nov. 15, 1993

Must be capable of removing 80% of the refrigerant, whether or not compressor is operating, or achieve 4 inch vacuum under the conditions of ARI 740

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Recovery eqpt. Manufactured after Nov. 15, 1993

Must be certified by an EPA testing laboratory as capable of recovering 90% of the refrigerant if the compressor is operating, 80% if it's not or achieve a 4 inch vaccum.

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The only way to read refrigerant pressure accurately is

A stable, known temperature.

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Air in a refrigeration system will cause

Higher discharge pressures

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System dependent recovery process on an appliance with an operating compressor

Run the compressor & recover from the high side of the system

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System dependent recovery process on an appliance with an non-operating compress

Access to both the low & high side of the system may be necessary.

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System dependent recovery devices may only be used on appliances containing

15 lbs. Of refrigerant or less

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Refrigerators built before 1950 may have used Methyl Formate , Methyl Chloride, or Sulfur Dioxide as refrigerant and should

Not be recovered with current recovery devices.

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Small appliances used in campers or other recreational vehicles may use refrigerants such as Ammonia, Hydrogen, or Water, and therefore should

Not be recovered using current recovery eqpt.

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When filling a graduated charging cylinder with a regulated refrigerant, the refrigerant vapor that is vented off the top of the cylinder

Must be recovered.

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After the installation of any type of system,

The unit should first be pressurized with nitrogen & leak checked

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In order to determine the general area of a leak use

An electronic or ultrasonic leak detector. Once the general area of the leak is located the use of soap bubbles will pinpoint the leak.l

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A refrigeration unit using open compressor that has not been used in several months is likely to

Leak from the rotating shaft seal

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EPA regulations require that all comfort cooling appliances more than 50lbs. Of refrigerant must be repaired when the annual leave rate exceeds

15%5

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EPA regulations require that all Commercial & Industrial Refrigeration containing more than 50lbs. Of refrigerant Must be repaired when the annual leak rate exceeds

35%

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Recovered refrigerants may contain acids, moisture, & oil

Frequently check & change both the oil & filter on a recycling machine.

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Before using a recovery unit you should always check the service value position, oil level of the recovery unit and

Evacuate & recover any remaining refrigerant from the units receiver.

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Technicians working with multiple refrigerants, before recovering & or recycling a different refrigerant, must purge the recover/recycle eqpt. by recovering as much of the first refrigerant as possible, change the filter, & evacuate.

The only exception to this rule is for technicians working with R-134A who must provide a special set of hoses,gauges,vacuum pump, recovery or recovery/recycling machine, & oil containers to be used with R-134A only.

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After recovery, refrigerant may be returned to the appliance from which it was removed or to another appliance owned by the same person without being recycled or reclaimed, unless the appliance is an MVAC like appliance.

The technician should always evacuate an empty recovery cylinder before transferring refrigerant to the cylinder. Quick couplers, self-sealing hoses, or hand valves should be used to minimize refrigerant release when hoses are connected & disconnected.

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System Dependant recovery eqpt. Can't be used on appliance containing more than

15lbs. Of refrigerant.

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The most common refrigerant used in residential split air conditioning system was

R-22, but now read the name plate to determine the type of refrigerant used.

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Filter drier will remove moisture from the refrigerant in a system, But there is a limit to their caspacity. Some system are eqpt. with a moisture indicating sight glass. When the sight glass changes color, the system contains excessive moisture & will

Need to be evacuated.The filter drier should be replaced anytime a system is open for servicing Strong odor detected, compressor burn out, watch for signs of contamination in the oil.

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

Refrigerant in the oil will cause oil foaming in the compressor at start up.

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When evacuating a vapor compression system, the vacuum pump should be capable of pulling 500 microns (29.90''hg) of vacuum.

The more accurate & preferred method of measuring a deep vacuum is in micron.

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The use of a large vacuum pump could cause trapped water to freeze.

During evacuation of system with large amounts of water, it may be necessary to increase pressure by introducing nitrogen to counteract freezing.

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The source of most none condensable is air .

None condensables will cause higher discharge pressures.

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Where there is a risk of freezing, liquid charging of an R-12 refrigerant system should begin with vapor from a vacuum level to a pressure of approx. 33psig.

Followed by a liquid charge thru. the liquid line service value

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Ashrae standard 15 requires a refrigerant senor that will sound an alarm & automatically start a ventilation system in occupied equipment rooms where refrigerant from a leak will concentrate.

Refrigerant CFC-12,CFC-11, & HFC-134a are categorized as A-1

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All refrigeration system must be protected by a pressure relief valve (s).

Must not be installed in series

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Never energize a reciprocating compressor if the discharge service value is closed

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Because a low pressure system operates below atmospheric pressure (in a vacuum),

Leaks in the gaskets or fittings will cause air & moisture to enter the system.

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The most effective method of leak checking a charged low pressure refrigerant unit is to pressurize the system by

The use of controlled hot water or heater blankets or use nitrogen to increase pressure.

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When pressurizing a system, don't exceed 10 psig

Exceeding 10 psig can cause the rupture disc to fail.

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When leak testing a water box

Be certain the water had been removed before placing the leak detector probe thru the drain value.

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To leak test a tube

Use a hydrostatic tube test kid.

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Systems with open drive compressors

Are prone to leaks at the shaft seal.

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Controlled hot water can be used to pressurize a system for the purpose of

Opening the system for non major repairs

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Under EPA regulations, a major repair means

Any maintenance, service or repair involving the removal: compressor, condenser, evaporator or any auxiliary heat exchanger coil.

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EPA regulations require that all comfort cooling appliances containing more than 50lbs. of refrigerant be repaired when

The annual leak rate exceed 15%

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EPA regulations require that all commercial & industrial process refrigeration containing more than 50lbs. of refrigerant be repaired when

The annual leak rate exceeds 35%

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A recovery unit's high pressure cut out is set for 10 psig when evacuating the refrigerant from a low pressure chiller and

A rupture disc on a low pressure recovery vessel relieves at 15 psig.

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Refrigerant recovery from a system using R-11 or R-123 starts with

Liquid removal & is followed by vapor recovery.

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A substantial amount of vapor will remain in the appliance after all liquid is removed.

For instance, an average 350 ton R-11 chiller at 0 psig still contains 100 lbs of vapor after all the liquid has been removed.

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When recovering refrigerant, the system water pumps and

Recovery compressor, recovery condenser water should be all be on.

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The ASHRAE guideline 3-1996 states that if the pressure in a system rises from 1 mm Hg to a level above 2.5 mm Hg during vacuum testing,

The system should be leak checked.

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A temp of 130°F should be attained when removing oil from a low pressure system

Few refrigerants is contained in the oil at this higher temperature.

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Recharging techniques

Refrigerant is added thru the lowest access point on the system,the evaporator charging value.

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Introducing liquid refrigerant into a deep vacuum will cause the refrigerant to boil and

May lower temperatures enough to freeze water in the tubes,thereofore, initial charging is in the vapor phase.

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Before charging with liquid an R-11 refrigerant system requires a vapor pressure of 26.9" Hg. vacuum, or

A saturation temperature of 36°F.

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Refrigerant Recovery & or recycling equipment manufacturered after November 15,1993 must be certified & labeled by an EPA approved equipment testing organization to meet EPA standards.

All equipment must have low loss fitting to minimize refrigerant loss when hoses are disconnected.

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Using recovery or recycling equipment manufactured or imported Before Nov.15,1993

25 inches Hg

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Using recovery or recycling equipment manufactured or imported on or After Nov.15,1993

25 mm Hg absolute

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Once the required vacuum has been achieved, the technician should wait for a few minutes & monitor the system pressure.

If the pressure rises, indicating that there is refrigerant remaining in the system,recovery must be repeated.

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When leaks in an appliance make evacuation to the prescribed level unattainable, the appliance should be

Evacuated to the lowest attainable level prior to a major repair.

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The use of large vacuum pump could cause trapped water to freeze.

During evacuation of the system with large amount of water, it may be necessary to increase pressure by introduce nitrogen to counteract freezing.

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If strong odor is detected during the recovery process, a compressor burn out may have occurred.

When recovering refrigerant from a system that experience a compressor burn out ,watch for signs of contamination in the oil.

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Because chillers using refrigerant such as CFC-11 & HCFC-123 operate below atmospheric pressure, they require a purge unit.

The primary purpose of a purge unit is to remove none condensable from the system.

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A centrifugal chiller's purge condensing unit takes its suction from the top of the condenser, removes air & other none condensable from the system, & returns refrigerant to the evaporator.

Although a high efficiency purge unit discharges a low percentage of refrigerant with the air they remove, frequent purging & subsequent refrigerant loss can indicate that a leak is allowing air into the system.

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High discharge pressure is also an indication of air in the system.

Excessive moisture collection in the purge unit can indicate tube leakage.

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To protect the system from over pressurization, low pressure chillers typically use a rupture disc mounted on the evaporator housing.

The typical design burst pressure for a rupture disc is 15 pisg.

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ASHRAE standard 15 requires a refrigerant monitor that will sound an alarm & automatically start a ventilation system in equipment rooms before the refrigerant concentration reaches the threshold limit value time weighted average.

A refrigerant monitor is required for all ASHRAE refrigerant safety groups.

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CFC-12, CFC-11, & HCFC-134 are coded grouped as A-1

R-123 is coded grouped as B-1

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All refrigeration system must be protected by a pressure relief valve (s)

Must not be installed in series.

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Created by: Rafael Leon