R-410A is a Refrigerant, also known as….?
SUVA – 410A……. AZ-20……Puron
The cylinder color code for R-410A is…?
HCFC-22 is scheduled for total phase out, by the year?
Suction and Discharge pressures for R-410A are how much higher than R-22 Systems?
40% to 70%
What is Temperature Glide?
A range of condensing and evaporating temperatures for one pressure.
When handling Refrigerants, Technicians should?
Wear approved eye protection and gloves/ Avoid loose fitting clothes.
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A full Nitrogen Cylinder has a pressure of…?
Nitrogen Cylinders should only be moved….?
1) with a protective cap in place 2) with an approved Cylinder cart.
Temperature Glide for R-410A is less than…?
0.3 degrees F
Why is R-410A a better choice than R-22 Refrigerant?
R-410A is more efficient, uses less energy, and has a lower TEWI
Due to it’s higher Vapor heat Capacity, what can be said of the Discharge Temperature of R-410A when compared to R-22?
Discharge temperature are lower.
Systems using R-410A must use what type of lubricant?
Polyol Ester Oil (POE)
What can be said of Polyol Ester Oils?
1) Can cause skin irritation 2) Is Hygroscopic..Draws moisture like a magnet 3) Has improved heat transfer characteristics over the mineral oils
How would one remove moisture from a Polyol Ester Oil?
Change the filter drier
When installing a liquid line filter dryer on a R-410A system, the dryer must have a pressure rating of how much psig?
What can be said of true Azeotropic Refrigerant?
Will not fractionate…..Has no Temperature Glide…..Is a single component Refrigerant
The closer a blend comes to being a true Azeotropic, what can be said of the Temperature Glide?
The glide in temperature will decrease
What can be said, if a Refrigerant blend is Zeotropic, or Near Azeotropic (NARM)?
Leaks may cause a change in the composition of the blend…..It will have a temperature glide….It will Fractionate
When charging a system with a blend that is Zeotropic, or Near Azeotropic (NARM), what must always be done?
It has to be transferred from the cylinders as a liquid to avoid Fractionation.
What is the negative result of a Near-Azeotropic blend Fractionalizing?
This can cause the components of the blend to leak at uneven rates, due to the varying Vapor Pressures.
What could be the result of a blend that has Fractionated, depending on the chemical make-up of the Refrigerant?
The Refrigerant could be flammable.
What must be be done to avoid Fractionation of a blended Refrigerant?
The Refrigerant has to be charged as a blended liquid.
What can be said of Sub-Cooled liquid stored in the Receiver?
It will lose or gain sub-cooling, depending on the surrounding ambient conditions
Why is R-407C a good choice for Retrofitting an R-22 Air Conditioning system?
R-407C temperatures and pressure are similar to that of R-22……..None ozone depleting
What is the color code for R-407C?
What is the disadvantage of R-407C, as compared to R-22?
It has a larger temperature glide.
What must be done when calculating Super-Heat with R-407C?
Super Heat must be done using a Dew Point value only.
What must be done when calculating sub cooling with R-407C?
Sub cooling must be done using a bubble point value only
How is compression ratio calculated?
Absolute Discharge Pressure divided by Absolute Suction Pressure
R-407C, also has another disadvantage as compared to R-22. What would be this disadvantage?
It will separate (Fractionate) into it’s component Refrigerant.
At what pressure does the Low Pressure Switch open on an R-410A?
At what pressure does the High Pressure Switch open on an R-410A?
610 psig, plus or minus 10 psig
How is Refrigerant charged into an operating R-410A system?
It has to be charged into the system as a blended liquid…….It has to be throttled into the Low Side to avoid compressor damage.
Some R-410A cylinders are equipped with a Dip Tube. What is the purpose of the Dip Tube?
It allows liquid to be removed with the cylinder in the upright position
The manufacturers of R-410A equipment have redesigned their compressors. What was done with the compressors?
The compressors all have increased wall thickness.
All service equipment used on R-410A systems, must be capable of doing what?
The equipment must be rated for higher pressures
The flow area of a R-410A Metering Device is what in relationship to a R-22 Metering Device?
About 15% smaller
At what pressure on a R-410A Manifold Gauge does the High Side pressure go to?
At what pressure on a R-410A Manifold Gauge does the Low Side pressure go to?
250 psig with a 550 psig retard
At what pressure does the Service Hoses have to be rated for, on an R-410A System?
What is the Compressor Internal Pressure Relief (IPR) settings for an R-410A System?
550 to 625 psig
R-410A systems should not be stored at a temperature warmer than what?
125 degrees F
What type of leak detector is needed for working with R-410A Systems?
One capable of sensing HFC Refrigerants.
What can be said of R-410A Refrigerant if the system develops a leak?
Remaining Refrigerant is OK to use, because R-410A has a low fractionation rate.
What type of Recovery Cylinders must be used with R-410A?
DOT 4BA 400………..DOT 4BW 400……..both cylinders are rated at a 400 psig burst strength
If the R-410A System uses a TXV Valve, what is the Proper method of charging the System?
If R-410A system uses a Capillary Tube or Fixed Metering Device, What is the proper method of charging the system?
Bubbles in a sight glass of R-410A, means the system is low on refrigerant…True or False?
The Evaporator Coil used with R-410A Systems, needs to meet what requirements?
UL approved design………Service pressure rating of 235 psig
If a large leak of Refrigerant occurs in a enclosed area, what should be done?
Vacate and Ventilate the area
What is the proper procedure when working on an Electrical Circuit?
Power has to be shut off…….The panel should be locked and tagged….Technician carries the keys to the lock