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77 Cards in this Set
- Front
- Back
heat pumps that use R- 410A should be leak check with |
pressurized nitrogen |
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Heat pumps that have been retrofitted from R-22 to R-407c should be leak checked with |
pressurized nitrogen |
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To change the compressor on a system containing R -410A you must isolate the compressor then |
Evacuate the isolated section of the system to atmospheric pressure and hold if system pressure does not rise remove the compressor |
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the method to change a system that has a normal charge of 80 pounds is to charge with |
Liquid through the liquid line service valve |
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After installation of a field piped R- 410A split heat pump the unit should first be |
Pressurized with nitrogen then leak checked |
|
Pressure relief valves must not be |
Installed in series |
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When charging an R12 refrigeration system that uses a water-cooled condenser you must first charged with Vapor to a pressure of at least ______before switching to liquid charging |
35 PSIG |
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Your recovery recycling machine has R22 refrigerant in it you now have to recover refrigerant from a unit with R-410A what must be done before your recovery unit can be used to recover R- 410A? |
the recovery unit must be EPA certified for us with r 410 a the recovery tank must be designed for the pressure of R 410 a the filter and lubricant in the recovery unit must be charged and the recovery unit evacuated( all of the above ) |
|
After reaching the required recovery vacuum on a system you must |
Wait to see if the system pressure Rises indicating that there is still refrigerant in liquid form or refrigerant trapped in the oil |
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In a refrigeration system the component directly following the evaporator is the |
Accumulator |
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A reciprocating compressor should not be energized |
The discharge service valve is closed |
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R410a requires a high pressure manifold gauge and hose that they must have a |
4000 PSIG burst pressure 800 PSIG working pressure |
|
The refrigerant pressure inside an R 410 a unit which is at room temperature and not operating is |
Approximately 210 PSIG |
|
Every air conditioning and refrigerating system should be protected by a |
Pressure relief device |
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To charge the compressor on a system containing 40 pounds R- 500 using a recycling machine that was manufactured AFTER November 15th 1993 you must isolate the compressor then |
Evacuate the isolated section of the system to 10 inches of vacuum and hold if system pressure does not rise remove the compressor |
|
When inspecting a system for leaks you should look for |
Traces of oil |
|
When a new system has been assembled the first thing to do is |
pressurize the system with an inert gas and leak check |
|
R-410A is different from other ASHRAE 400 series non azeotropic blends because |
R-410A behaves as a near azeotropic refrigerant and can be topped off |
|
Manifold gauge set hoses should have self-sealing connectors or hand valves to |
Minimize the release of refrigerant when the hoses are connected and disconnected |
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When using recovery or recycling equipment that was manufactured AFTER November 15th 1993 must evacuate a system containing MORE than 200 pounds of CFC 12 to_____ before making a major repair |
15 inches of HG vacuum |
|
With an air-cooled condenser on the roof of a building in the evaporator on the first floor recovery should first occur |
From the liquid line entering the evaporator |
|
Never use oxygen or compressed air to leak check Hardware because R 410A can |
Explode when mixed with air or oxygen |
|
Dry nitrogen should be used to break the first vacuum when dehydrating by the double evacuation method however it |
Can be dangerous if not used with a pressure regulator |
|
A recovery machine that uses a hermetic compressor will overheat when drawing a deep vacuum because |
The motor needs the flow of refrigerant through the compressor to provide motor Cooling |
|
The proper charging method for Blended non isotropic refrigerant 400 series is to use a remove the charge from the cylinder as a |
Liquid |
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When a refrigerant Trace gas becomes absolutely necessary which of the available refrigerant should be used to identify a leak? |
HCFC-22 |
|
After refrigerant liquid has been removed from a system any remaining vapor is |
Condensed by the recovery system |
|
an oil sample should be taken when |
the compressor has a burnout |
|
In a refrigeration system with a TXV or other type of throttling device the component directly following the condenser is the |
Receiver |
|
Recovered refrigerant may contain which of the following? |
Acids moisture & oils (all of the above ) |
|
The back seating of a suction shutoff valve will close the |
Gauge port |
|
Which repair would always be considered major under EPA's regulations? |
Replacement of an evaporator coil |
|
R410a require Certified Recovery and recycling machines rated for at least |
400 PSIG |
|
A compressor heater is used to |
Reduce the amount of refrigerant in the lubricating oil |
|
Your recovery recycling machine has r502 refrigerant in it you now have to recover refrigerant from a unit with R22 what must be done before the R-22 refrigerant can be recovered recycled? |
Recover as much of the r502 from The Recovery Unit as possible change filter and evacuate |
|
The faster way to recover refrigerant from a system is to remove it in the _____ phase? |
Liquid |
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Before using every covery unit to remove a charge what steps should be taken |
Check service valve positions check the oil level in The Recovery Unit evacuate Recovery Unit and recovery tank(all of the above ) |
|
A deep vacuum is usually measured in |
Microns |
|
Before transferring refrigerant to an empty cylinder? |
The cylinder should be evacuated to avoid mixing air with the recovered refrigerant |
|
To recover liquid refrigerant you must connect one hose to the |
Liquid line |
|
A system can be evacuated to only atmospheric pressure when |
Leaks in the Appliance make evacuation to the prescribed level unattainable |
|
A system can be evacuated to only atmospheric pressure when |
Leaks in the Appliance make evacuation to the prescribed level unattainable |
|
The vacuum pump used to evacuate a system should be capable of pulling a vacuum of |
500 microns |
|
While r410a is a high pressure refrigerant it can be stored in the back of your service van as long as |
The temperature inside the vehicle does not exceed 125F this is the same guidance given for R22 and other common refrigerant |
|
When under a deep vacuum the motor winding of a hermetic Refrigeration compressor |
Will overheat only if the crankcase heater is energized |
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Which statement is not true about Recycling and Recovery equipment manufactured after November 15th 1993? |
it must have an oil separator |
|
When are you getting it is opened for servicing the______ should always be replaced |
Filter drier |
|
When servicing an operating unit that has a receiver storage tank the |
Refrigerant should be recovered into the receiver |
|
Use_____ to remove ice from a sight glass |
An alcohol spray |
|
The refrigerant pressure inside an R12 unit which is at room temperature and not operating is |
Approximately 74 PSIG |
|
You are going to service a newer residential split system air conditioner you would expect to find the system charged with which refrigerant? |
R-410A |
|
A routine maintenance tasks which must be performed on refrigerant recycling machines is to |
Change filter in compressor oil (if any) |
|
refrigerant should be removed from the condenser Outlet if the |
condenser is below the receiver |
|
when evacuating a system the use of a large vacuum pump could |
cause trapped water to freeze |
|
On refrigeration units that use an open compressor the_____ is most likely to leak if the unit is not used for several months |
Rotating shaft seal |
|
The primary water source for cooling the condenser of a water cooled Recovery Unit is |
local Municipal Water Supply |
|
when using recovery and recycling equipment manufactured BEFORE November 15th 1993 technicians must evacuate a unit that has a normal charge of 10 pounds of CFC 500 to ______ before disposing of the system |
4 inches of Hg vacuum |
|
the evaporation temperature of R 410A at 100 PSIG is about |
30°F |
|
Noncondensables in a system cause a |
Higher discharge pressure |
|
R 410 A requires recovery tanks rated for at least |
400 PSIG |
|
The recovery rate can be increased by |
Packing the recovery vessel in ice |
|
Oil foaming usually occurs in the |
Compressor |
|
During the evacuation of a system that contains large amounts of moisture it may be necessary to increase pressure in the system with_____ to counteract the freezing of the moisture |
Nitrogen |
|
Prior to replacing the condenser coil in a high pressure system the refrigerant was recovered and stored in a refillable cylinder the refrigerant |
can probably be charged back into the system |
|
The evaporation temperature of R134a at 0 PSIG is |
-15°F |
|
The EPA regulations require that any appliances containing more than 50 pounds of refrigerant except for commercial and Industrial process Refrigeration must be repaired when the leak rate exceeds_____ of the charge per year |
15% |
|
The EPA regulations require that leaking commercial or industrial process Refrigeration equipment must be repaired when the leak rate exceeds_____ of the charge per year |
35% |
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You are going to service an older residential split system air conditioner you would expect to find the system charged with which refrigerant |
R-22 |
|
For what refrigerant is an equipment room Refrigeration monitor required under ASHRAE standard 15? |
R-123 |
|
Heat pumps that use R134A should be leak checked with |
Pressurized nitrogen |
|
On a high pressure system______ is an indicator of a possible leak |
excessive super heat |
|
system dependent recovery equipment cannot be used with |
Appliance contains over 15 pounds of refrigerant |
|
moisture is removed from a system by |
using a filter drier |
|
which component is not part of the low side of the system |
Receiver |
|
Soap bubble testing is used |
To pin point refrigerant leaks |
|
Refrigerant leaves the receiver of a system as a |
High pressure liquid |
|
The recovery of refrigerant from a system as a vapor only will minimize the loss of |
Oil |