unit 50
Typically, on mini-split systems the line set going to the outdoor unit carries ________ pressure, ________ temperature saturated liquid and vapor mix. The line going back to the outdoor unit carries ________ pressure superheated vapor.
high, high, low
low, high, high
Correct Answer
low, low, low
low, high, low
0 / 1 pts
Which of the following mini-split system indoor units requires a condensate pump because gravity condensate draining is never feasible for this type of installation?
Wall mount
Correct Answer
Ceiling suspended
Floor mount
All of these
0 / 1 pts
Variable refrigerant flow systems use:
Inverter driven systems and thermostatic expansion valves.
Correct Answer
Inverter driven systems and electronic expansion valves.
Scroll compressors and electronic expansion valves.
Scroll compressors and thermostatic expansion valves.
0 / 1 pts
Manufacturers recommend pressurizing VRF piping to ________ with nitrogen and performing a 24 hour standing leak test.
200 - 300 psig
300 - 400 psig
400 - 500 psig
Correct Answer
500 - 600 psig
0 / 1 pts
Standard wyes and tees are not used in VRF refrigeration networks as they introduce turbulence and do not ensure even flow to both branches.
Correct Answer
True
False
A type system that allows simultaneous heating and cooling to different parts of a building is the:
Multisplit system.
Heat pump variable refrigerant flow system.
Correct Answer
Heat recovery system.
All of these.
0 / 1 pts
Designing a heating and cooling system to accommodate load shifts:
Allows buildings to operate with less installed capacity and still meet the demand.
Improves comfort.
Improves efficiency.
Correct Answer
All of these.
UnansweredQuestion 8
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Some codes limit refrigerant 410A to 25 pounds per 1000 cubic feet of space. This works out to 40 cubic feet per pound of refrigerant. The limit is lower, ________ cubic feet per pound of refrigerant for 24 hour care facilities such as hospitals and nursing homes.
15
Correct Answer
20
30
50
UnansweredQuestion 9
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Most multisplit units require connection to:
All of the circuits.
At least four indoor units, but not all of the circuits have to be used.
At least three indoor units, but not all of the circuits have to be used.
Correct Answer
At least two indoor units, but not all of the circuits have to be used.
UnansweredQuestion 10
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Mechanical codes limit the amount of refrigerant a system can contain if it is located in an occupied space. Because VRF systems are connected to one large refrigerant network that would release the entire charge in case of a leak, some codes limit refrigerant 410A charge to ________ pounds per 1,000 cubic feet of space.
15
Correct Answer
25
30
50
UnansweredQuestion 11
0 / 1 pts
Which of the following is NOT a type of indoor unit used on mini-split systems?
Wall mount
Ceiling suspended
Floor mount
Correct Answer
Crawl space
UnansweredQuestion 12
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The typical number of wires connecting the outdoor unit to the indoor unit of a mini-split system is:
Two.
Three.
Correct Answer
Four.
Any of these.
UnansweredQuestion 13
0 / 1 pts
Flare connections are used on mini-split systems to avoid oxidation in the lines and also to avoid heating and destroying the sensitive electronic expansion valves use in the outdoor units.
Correct Answer
True
False
UnansweredQuestion 14
0 / 1 pts
What type of refrigerant line connections are used on multisplit systems?
Multiple connections on the outdoor unit
Single set of connections on the outdoor unit
A refrigeration network similar to a heat recovery system
Correct Answer
Both Multiple connections on the outdoor unit and Single set of connections on the outdoor unit could be used.
UnansweredQuestion 15
0 / 1 pts
The wiring connection between the outdoor and indoor unit typically has four wires. One wire carries power, a second wire carries low voltage communication while a third wire carries both line voltage power and low voltage communication. A fourth wire is utilized for ground.
Correct Answer
True
False
UnansweredQuestion 16
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Designing a heating and cooling system to accommodate load shifts can allow buildings to operate with ________ capacity to meet the demand.
more installed
Correct Answer
less installed
UnansweredQuestion 17
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It is possible for one multi-split indoor unit to heat while another cools.
True
Correct Answer
False
UnansweredQuestion 18
0 / 1 pts
Multisplit manufacturer's installation instructions will specify the maximum total installed piping length which can be supported by the charge shipped in the unit. If additional piping is installed the only correct way to charge the system is to:
Charge the system to the required subcooling.
Charge the system to the required superheat.
Correct Answer
Add the specified amount of refrigerant for each additional foot of refrigerant line.
None of these.
UnansweredQuestion 19
0 / 1 pts
The smallest capacity VRF outdoor units available generally equal or exceed the largest multisplit units available.
Correct Answer
True
False
UnansweredQuestion 20
0 / 1 pts
VRF systems are commercial systems. The outdoor units are normally designed to operate on ________ phase power and the indoor units on ________ phase power.
single, single
single, three
three, three
Correct Answer
three, single
UnansweredQuestion 21
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When more than one indoor unit is connected an individual branch selection box on a heat recovery system:
Correct Answer
Each indoor unit must operate in the same mode.
One indoor unit may operate in the heat mode and other(s) may operate in the cooling mode.
UnansweredQuestion 22
0 / 1 pts
Mini-split condensate pumps come in three basic varieties: two-piece pumps, monoblock pumps, and:
Multisplit pumps.
Peristaltic pumps.
Sump pumps.
Correct Answer
Reservoir pumps.
UnansweredQuestion 23
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When factory supplied branch joints are not available for VRF refrigerant piping it is permissible to use standard tees or wyes.
True
Correct Answer
False
UnansweredQuestion 24
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Like many multisplit units, variable refrigerant flow (VRF) systems use ________ compressors and electronic expansion valves to change the volume of refrigerant being circulated in the system.
scroll
reciprocating
screw
Correct Answer
inverter driven
UnansweredQuestion 25
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It is important when wiring multisplit systems that the indoor units connect to their corresponding A, B, C, or D terminal block on the outdoor unit.
Correct Answer
True
False
UnansweredQuestion 26
0 / 1 pts
Which system allows simultaneous heating or cooling?
Mini-split system
Multisplit system
Correct Answer
Heat recovery system
UnansweredQuestion 27
0 / 1 pts
While multisplit units are limited to a single outdoor unit, large VRF systems can combine as many as ________ outdoor units manifolded together to increase overall system capacity.
two
Correct Answer
three
four
five
UnansweredQuestion 28
0 / 1 pts
Power for the mini-split system is supplied:
Correct Answer
To the outdoor unit which powers the indoor unit.
To the indoor unit which powers the outdoor unit.
To the indoor and outdoor with their own separate dedicated wiring and circuit protection.
Any of these methods may be used.
UnansweredQuestion 29
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On heat recovery systems:
It is required that all indoor units be in cooling mode.
It is required that all indoor units be in heating mode.
Correct Answer
One indoor unit can be in heating mode while others are in cooling mode at the same time.
Both It is required that all indoor units be in cooling mode and It is required that all indoor units be in heating mode.
UnansweredQuestion 30
0 / 1 pts
Some multisplit systems operate all indoor units from one control while others allow individual indoor units to operate from their own controls and set points.
Correct Answer
True
False
UnansweredQuestion 31
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The refrigerant lines for single zone mini-split air conditioners are usually connected by:
SAE compression fittings.
Brazed connections.
Correct Answer
Flare fittings.
Reflok fittings.
UnansweredQuestion 32
0 / 1 pts
To avoid the creation of oxides in the refrigeration lines of mini-split systems, the lines are assembled:
By brazing the connections while flowing nitrogen through the lines.
Using Reflok fittings.
Correct Answer
Using heavy-walled flare fittings.
Using standard flare fittings.
UnansweredQuestion 33
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VRF systems use a refrigeration network of:
Wyes and tees.
Correct Answer
Headers and branch joints.
Both Wyes and tees and Headers and branch joints.
None of these.
UnansweredQuestion 34
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On mini-split systems both refrigerant lines must be insulated because they are both:
Low pressure and low temperature in the heating mode.
Correct Answer
Low pressure and low temperature in the cooling mode.
Low pressure and low temperature in the heating and cooling mode.
Low pressure and high temperature in the cooling mode.
UnansweredQuestion 35
0 / 1 pts
Most systems can operate with up to ________ feet of lines and a maximum of ________ feet vertical distance between the indoor and outdoor units.
Correct Answer
50, 10
75, 15
90, 20
100, 30
UnansweredQuestion 36
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Branch selectors are boxes in heat recovery VRF systems that allow:
Correct Answer
One refrigerant line to feed multiple indoor units.
One refrigerant line to feed a single indoor unit.
Multiple refrigerant lines to feed multiple indoor units.
Multiple refrigerant lines to feed a single indoor unit.
UnansweredQuestion 37
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Wiring for a four-port multisplit system runs:
One wire to each indoor unit.
Two wires to each indoor unit.
Three wires to each indoor unit.
Correct Answer
Four wires to each indoor unit.