WorksheetsCHS type III
Total questions: 77
Worksheet time: 39mins
What type of appliance can a technician work on with a Type III Certification?
Convenience store refrigerators
Ice machines that fit under the counter
Low pressure appliances such as chillers
High pressure appliances such as heat pumps
Low pressure appliances operate...
As a high pressure system.
In a vacuum or below atmospheric pressure.
Above atmospheric pressure.
Where does the purge unit take its suction from?
The lowest point of the system
The top of the condenser
The evaporator charging valve
The bottom of the condenser
What is the pressure relief device on a low-pressure chiller called?
A vent pipe
A purge unit
An evaporator valve
A rupture disc
What is the boiling point of R-123 refrigerant at atmospheric pressure?
0 degrees F
83 degrees F
- 15 degrees F
26 degrees F
When charging a low pressure water chiller with R-123, charging begins with vapor, until what pressure is reached in the system?
25 "hg
18.9 "hg
0 "hg
84 psig
If the condensing temperature of a low pressure chiller is 100 degrees F, that means the high side pressure is:
19 psig
6.1 "hg
83 psig
6.1 psig
What do CFC-11, HCFC-123, HFC-245fa, and HFO-1233zd have in common?
They all contain chlorine
They are low pressure refrigerants that have low boiling points
They are high pressure refrigerants that have high boiling points
They are low pressure refrigerants that have high boiling points
What do low pressure appliances require since they operate below atmospheric pressure?
A pressure relief valve
A purge unit
A condenser
A process stub
What is the most effective way to leak test a charged low pressure chiller?
Use controlled hot water or electric heating blankets to increase system pressure
Use an open flame to speed up the system
Add nitrogen to the system
Use cold water and ice decrease system pressure
Why should a technician NEVER add nitrogen to a charged low pressure appliance for the purposes of leak detection?
It will mix with the refrigerants and oils in the system
It will result in inaccurate pressure readings
It will decrease the system pressure
It will cause the purge unit to operate resulting in refrigerant loss
When pressurizing a low pressure appliance for the purpose of leak detection DO NOT exceed ____.
25 psig
10 psig
30 psig
17 psig
What happens when a low pressure system exceeds 10 psig and the rupture disk opens?
Nothing
The system leaks oil
The moisture in the system is released
The system vents refrigerant
What can happen when a low pressure appliance has a leak at a fitting or gasket?
Water can spill from the system
Air and moisture can enter the system
The fitting or gasket can corrode and may need to be replaced
refrigerant can leak from the system
What should be done if a purge unit that is operating excessively?
check voltage to the purge unit
pressurize the unit and leak test
evaluate the refrigerant charge
clean the units water tubes
Which of the following can be used to pressurize a charged, low pressure chiller for the purpose of leak detection?
nitrogen
R410a refrigerant
running the compressor at full speed
controlled hot water or heating blankets
What is used to leak test a water tube in a chiller?
hot water above 125 degrees F
hydrostatic tube test kit
refrigerant
standing vacuum test
To leak test the water box of a chiller, drain the water and place the leak detector probe in:
the drain valve
the evaporator charging valve
suction of the purge unit
one of the water tubes
As of 2019, a chiller used for comfort cooling needs to be repaired when the annual leak rate exceeds ____.
20% of the charge
30% of the charge
10% of the charge
15% of the charge
How long does an owner have to retrofit or retire a low pressure appliance that has exceeded the leak rate threshold?
6 months
18 months
24 months
4 months
How long does an owner have to repair a leaking low pressure appliance to below the leak rate threshold and get an initial verification test?
60 days
15 days
30 days
90 days
How long does the owner or operator need to keep leak inspection, leak repair verification test, and follow up verification test records?
13 years
3 years
20 years
5 years
Recovery equipment manufactured on or after November 15, 1993 must be capable of achieving a recovery level of ____.
45 mm Hg
35 mm Hg
30 mm Hg
25 mm Hg
When a leak in a low pressure appliance makes the required recovery level unattainable the appliance should be evacuated to ____.
10 psig
25 psig
0 psig or atmospheric pressure
5 psig
Why should all recovery equipment be fitted with low-loss fittings?
To minimize moisture from entering the system
To minimize oxygen from escaping when hoses are disconnected
To minimize refrigerant loss when hoses are disconnected
To minimize oil loss when hoses are disconnected
After the required level is reached on a low pressure appliance what can indicate that there is still refrigerant remaining in the system?
A rise in pressure after the recovery unit is turned off
Moisture in the system
Air in the system
A drop in pressure after the recovery unit is turned off
Refrigerant recovery on a low pressure appliance begins with ____.
Liquid removal
Vapor removal
Condensing
Oil removal
After recovering liquid refrigerant from a low pressure chiller what remains in the system?
A substantial amount of vapor
Liquid refrigerant
No refrigerant
Non-condensables only
What should be done with the remaining vapor in a low pressure appliance after the liquid has been recovered?
It stays in the compressor
It is vented into ambient air
It is removed and condensed by the recovery unit
It is left inside the appliance
What is the high-pressure cut out control typically set for on a recovery unit designed for recovering refrigerant from a low-pressure chiller?
5 psig
10 psig
30 psig
25 psig
Approximately how much vapor refrigerant would remain in a typical 350 ton, R-123 chiller after all the liquid refrigerant has been removed?
About 10,000 lbs of refrigerant
About 10 lbs of refrigerant
About 350 lbs of refrigerant
About 100 lbs of refrigerant
Why is it important that prior to removing oil from a low pressure system, the oil be heated to 130 degrees F?
the oil will flow more freely
less refrigerant will be contained in the oil
to drive moisture and other contaminants from the oil
to ensure all oil is removed
When charging R 123 refrigerant into a low pressure chiller, charging should begin with vapor until what pressure is reached?
20 inches of mercury vacuum
18.5 inches of mercury vacuum
19.1 inches of mercury vacuum
25.9 inches of mercury vacuum
On a low pressure chiller, where is refrigerant added?
the liquid line king valve
the condenser charging valve
the evaporator charging valve
the compressor suction valve
Which of the following must be accounted for in leak rate calculations?
adding refrigerant to a new system
adding refrigerant to a newly retrofitted system
all answers are correct
topping off the system with refrigerant due to a leak
What should be on to prevent freezing, when recovering refrigerant from a low pressure chiller
all answers are correct
the system water pumps
the recovery unit condenser water
the recovery unit compressor
ASHRAE guideline 3 states that a low pressure chiller should be pressurized and leak tested, if during a standing vacuum test, the pressure rises from ____ to _____:
29 inches mercury to 10 inches of mercury
0 psig to 10 psig
1 mm to a level above 2.5 mm
2.5 mm to a level above 25 mm
If a chiller is suspected of tube leaks, what should be done prior to refrigerant recovery?
drain the water from both the evaporator and condenser sides of the system
drain the water from the condenser side of the system
drain the water from the evaporator side of the system
repair the tube leaks
If a compressor burn out has occurred during the recovery process what should you look for in the system?
water in the system
the type of refrigerant
signs of contamination in the oil
the compressor wires
Where does the purge unit take its suction from?
the lowest point of the system
the top of the condenser
the evaporator charging valve
the bottom of the condenser
After the purge unit on a low pressure chiller separates the non-condensables from the refrigerant where does the refrigerant go to next?
the compressor
the evaporator
the condenser
the atmosphere
What can frequent operation of the purge unit and excessive refrigeration discharge pressure indicate in a low pressure appliance?
the condenser needs to be replaced
excessive refrigerant in the system
a compressor burnout during recovery
a leak that's allowing non-condensables (air) into the system
Where is refrigerant added to on a low pressure chiller?
through the highest part of the system
through the pressure relief device
through the evaporator charging valve
through the purge unit
What is required by ASHRAE Standard 15 in each equipment room when the TLV-TWA (threshold limit value-time weighted average) is exceeded?
An alarm and a mechanical ventilation system
Stationed technicians
Fire sprinklers
Emergency recovery devices
What does ASHRAE require for all refrigerant safety groups?
Fire alarms
A gauge manifold
A purge valve
A refrigerant monitor
Which class of refrigerants has shown evidence of toxicity below 400 ppm?
Class C
Both Class B and C
Class B
What is the ASHRAE code classification for CFC-12, CFC-11, and HFC-134a?
A1 (non-toxic, non-flammable)
A3 (low toxicity, highly flammable)
B1 (toxic below 400ppm, non-flammable)
If more than one pressure relief device is used in a refrigeration system, how must they be piped in?
Parallel to each other
In series to each other
On a low pressure chiller, where should the vent pipe from the rupture disk lead to?
To the outdoors
Into the basement
Into the equipment room
Into an unoccupied room
Which of the following refrigerants is safety classified as a B1 refrigerant(high toxicity/low flammability)?
R 134a
R 123
R 22
R 11
Where is the rupture disc located?
on top of the water box
on the purge unit
on the evaporator housing
on the condenser outlet
Excessive moisture collection by the purge unit may indicate which of the following?
dirty condenser tubes
dirty evaporator tubes
tube leakage
shaft seal leak on compressor
What precaution should be taken prior to recovering refrigerant from a chiller suspected of having tube leaks?
Drain the water sides of the evaporator and condenser.
Run the circulating pumps.
Be certain the purge unit is operating.
Open the condenser vents.
Which of the following is NOT required for an appliance that is using an ozone-depleting refrigerant to be mothballed (thereby extending the leak repair deadline)?
Shut down the appliance temporarily.
Evacuate the refrigerant from the isolated section or component.
Evacuate refrigerant from the appliance to at least atmospheric pressure.
Remove the appliance and store it in a warehouse at the facility.
Excessive running of a purge system on a low-pressure chiller generally indicates what condition?
Faulty air sensors
Leaking system
Ambient temperature is too high
Low purge unit efficiency
Where should the discharge from a rupture disc be piped for venting?
Outdoors
To the duct system
To the evaporator
Inside the machinery room
A company uses a chiller that diverts 55% of its cooling capacity to one of its manufacturing lines and 45% of its cooling capacity to air condition the office spaces. Which leak rate category is this chiller in?
Industrial process refrigeration
Ice making refrigeration
Commercial refrigeration
Comfort cooling
Where is the rupture disc located on a centrifugal chiller?
Condenser
Evaporator
Liquid line
Economizer
What should you do after reaching the required recovery vacuum on a low-pressure appliance?
A.
Immediately disconnect the recycling or recovery equipment, and open the system for service.
Wait for at least a few minutes to see if the system pressure rises before charging.
Break the vacuum with nitrogen and open the system for service to begin charging liquid.
Pressurize the system with nitrogen and perform a leak check.
Which component is particularly susceptible to leaks in low-pressure refrigeration systems with open drive type compressors?
Chiller tubes
Shaft seal
Charging connections
Shaft bearings
What is the result of raising the temperature of the room in which a low-pressure chiller is located?
Lower pressure in the chiller.
Faster refrigerant recovery.
Delayed recovery.
Reduced oil flow.
1. Which of the following statements about R-1233zd is FALSE?
It is a SNAP approved replacement for low-pressure centrifugal compressor systems.
It is being considered for applications where R-123 might have been used.
It is suitable for air conditioning applications where cooling water is used (large chiller applications).
It is mildly flammable.
When evacuating a system, the use of a severely oversized vacuum pump could;
cause trapped oil to freeze.
cause trapped refrigerant to freeze.
cause trapped water to freeze.
cause the valves to freeze.
When does ASHRAE Standard 15-2013 require that each machinery room activate an alarm and mechanical ventilation?
When the TLV-TWA (Threshold Limit Value -Time Weighted Average) is exceeded.
When the UTL (Upper Threshold Limit) is exceeded.
When the COP (Coefficient of Performance) drops 5% of the original value.
When the EEL (Emergency Exposure Limit) is exceeded by 10%.
Which of the following is a reason to take an oil sample?
A new filter drier has been installed.
The unit has had a compressor burnout.
The unit is not cooling properly.
Recycled refrigerant has been added to the unit.
Starting in 2019, what is the leak rate threshold for commercial refrigeration equipment with a full charge of 50 or more pounds of an HCFC refrigerant?
30%
20%
10%
5%
After system servicing, and recharging, why is refrigerant vapor re-introduced to the chiller before refrigerant liquid?
Vapor charging increases pressure slowly, preventing failure of the rupture disk.
Vapor charging is faster than liquid charging.
Liquid charging is more difficult to control than vapor charging.
Liquid charged into a deep vacuum will evaporate and may lower the temperature freezing water in the heat exchanger tube bundle.
What should be on and what should be off during vapor removal from a low-pressure refrigeration system?
The system water pumps should be on and the recovery compressor should be off.
The system water pumps and recovery compressor should be on, and the recovery condenser water should be off.
The system water pumps, recovery compressor, and recovery condenser water should all be on.
The system water pumps should be off, and the recovery compressor should be on.
During evacuation of a system containing large amounts of moisture, it may be necessary to prevent freezing by increasing pressure using a gas such as;
air.
carbon dioxide.
R-134a.
nitrogen.
Which of the following CANNOT be used as a reason to extend the appliance leak repair deadlines?
Requirements of federal, state or local regulations make the repair within 30 days impossible.
The appliance is located in an area that is subject to radiological contamination.
Necessary repair parts are unavailable.
A certified service technician is not available.
Leak testing a low-pressure refrigeration system with nitrogen in excess of 10 psig could cause which of the following to fail?
Condenser tubes
Purge unit shells
Evaporator tubes
Rupture disc
Which of the following actions would always be considered "major" under EPA's regulations?
Replacement of an evaporator coil
Replacement of a filter-drier
Replacement of a switch
Replacement of a purge unit
Identify the pressure corresponding to 32°F for R-123.
23 inches of Hg vacuum
20 inches of Hg vacuum
17 inches of Hg vacuum
11 inches of Hg vacuum
When leak testing a low-pressure centrifugal with nitrogen, what is the maximum test pressure?
0 psig
10 psig
25 psig
50 psig
How do you determine when enough vapor has entered the refrigeration system before you charge refrigerant liquid?
Refrigerant saturation temperature increases above 32°F.
Recovery unit liquid level drops to a lower pressure.
Vapor is charged for 15 minutes and then liquid is added.
Recovery unit pressure drops to a lower pressure.
What is a typical advantage of a water cooled recovery unit?
Higher pressure at the recovery compressor's discharge.
Higher pressure in the recovery tank.
Faster recovery of large quantities of refrigerant.
Greater percentage of refrigerant recovered.
Continuous excessive moisture collection in the purge unit of a low-pressure refrigeration system could indicate what condition?
The system was charged with contaminated refrigerant.
The condenser or chiller barrel tubes are leaking.
The purge unit is not operating properly.
The purge adjustment is not set properly.
