410A test
The temperature glide for R-410A is less than ________ degrees Fahrenheit over air conditioning and refrigerating operating ranges.
0.3
R-410A cylinders should not be allowed to get warmer than?
125 degree Fahrenheit
HCFC-22 is scheduled for total phaseout in the year?
2020
Manifold low side gauge for R-410A refrigerant must range to?
250 psig with 500 psig to 550 psig retard
A full nitrogen cylinder has a pressure of approx?
2500 psig
Both suction and discharge pressures of R-410A systems are ________ than R-22
40%-70% higher
The low pressure control on R-410A systems will open at?
50 psig
Compressor internal pressure relief (IPR) settings for R-410A systems are?
550 psig to 625 psig
When installing a liquid line filter drier on a R-410A system, be certain that it has a pressure rating of at least:
600 psig
R-410A systems use a high pressure switch that will open at approximately?
610 psig plus or minus 10 psig.
Manifold high side gauge for R-410A refrigerant must range to?
800 psig
Service hoses used with R-410A equipment must be rated to?
800 psig
Temperature glide refers to
A range of condensing and evaporating temperatures for one pressure.
Compression ratio is calculated as?
Absolute discharge pressure divided by absolute suction pressure.
When charging an operating R410A system with liquid refrigerant
Be sure it is throttled into the low side to avoid compressor damage
Polyol Ester (POE)
Can be irritating to the skin, is hygroscopic and has improved heat transfer characteristics over mineral oils.
Near- azeotropic blends fractionation may
Cause the components to leak at uneven rates due to varying vapor pressures.
To remove moisture from polyol ester (POE) lubricant
Change filter/drier and evacuate to 500 microns
Recovery cylinders used with R-410A must have DOT rating of?
DOT 4BA 400 or DOT 4BW 400
Subcooled liquid in the receiver may ________ subcooling, depending on surrounding conditions.
Either gain or lose.
Blends that have fractionated, depending on the constituent make-up, may become
Flammable
A leak detector capable of sensing ________ is needed when working with R-410A
HFC
R-410A;
Is more efficient than R-22, using less energy, therefore it has a lower TEWI
Which of the following statements is true of R-407C? R-407C is a single component refrigerant It is classified as an azeotropic refrigerant It is a binary blend or It may separate (fractionate) into its component refrigerants.
It may separate (fractionate) into its component refrigerants.
When a blend is zeotropic or near-azeotropic (NARM)
It should be transferred from cylinders as a liquid to avoid fractionation.
When a blend is zeotropic or near-azeotropic (NARM)
Leaks may cause a change in composition of the blend, it will have temperature glide, and it can fractionate.
Because of its higher vapor heat capacity, the discharge temperature of R-410A is ________ than R-22
Lower
All service equipment used with R-410A
Must be rated for the higher pressures.
Systems containing R-410A ________ lubricant
Polyol ester
Before working on any electrical circuit
Power should be shut off, locked and tagged at the distribution panel.
It has a high temperature glide is true about what refrigerant?
R-407C
What refrigerant is a good choice for retrofitting an R-22 air conditioning system?
R-407C
The evaporator or indoor coil should be ________ when changing out of existing R-22 equipment to a new R410A system
Replaced with one that meets UL approved design and service pressure rating if 235 psig
The cylinder color code for R-410A is:
Rose
To avoid fractionation, blended refrigerants:
Should be charged in the liquid phase
The flow area of a R-410A metering device is?
Smaller than that of a R-22 metering device.
When charging a R-410A system that uses a thermostatic expansion valve, proper charge can be determined by measuring?
Subcooling
When charging a R-410A system that uses a capillary tube or fixed metering device, proper charge can be determined by measuring?
Superheat
R-410A is also known as?
Suva 410A, AZ-20 and Puron
A system using R-410A refrigerant has bubbles in the sight glass. Technician A says that the system must be low on refrigerant. Technician B says that the bubbles could be caused by the blended refrigerant flashing in the increased volume of the sight glass. Who is correct?
Technician B
The closer the blend comes to being a true azeotrope,
The less the temperature glide it will have.
If a R-410A system develops a leak:
The remaining refrigerant is ok to use because R-410A has a low fractionation rate
Cylinders containing R-410A that are equipped with dip tubes,
To allow liquid to be removed with the cylinder upright.
When calculating subcooling with R-407C
Use the bubble point value only.
When calculating superheat with R-407C
Use the dew point value only.
If a large leak of refrigerant occurs in an enclosed area, you should?
Vacate and ventilate the area
When handling refrigerants, technicians should?
Wear approved eye protection and gloves.
A true azeotropic blend
Will not fractionate, has no temperature glide, qnd behaves as a single component refrigerant.
Manufacturers of equipment using R-410A have redesigned their compressors
With increased wall thickness
Nitrogen cylinders should only be moved
With the protective cap in place.