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The flashcards below were created by user
salvatorefricano
on FreezingBlue Flashcards.
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A typical chilled water system is desingen to operate with leaving water temperature off the chiller coil at what degree F*
45*F
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who discovered the theory of Absorption systems
- Michael Faraday
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Centrifugal chillers range in size from tons
10 to 10,000 tons
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On an R-11 or R-123 system, the refrigerant removal process normally starts with the removal of ?
- Liquid refrigerant
- push-pull recovery method
- will speed up process by 150%
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A chiller filled control circuit does what?
- Is a circuit that starts the control procedure before the compressor starts
- Is often called an interlock system.
- Ensures that appropriate fans and pumps are started in the proper sequence.
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Which of the following is not a large positive displacement compressor
Centrifugal
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water-cooled chillers must have water treatment to do what.
- minimize mineral and algae deposits
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The ideal cooling tower temp of a lithium bromine absorption system is 85*F. What is a likely result if this temp drops to 75*F.
Crystallization occures
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Positive displacement compressors have crankcase heat for what.
To Prevent refrigerant migration of the compressor.
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Tools used to check compressor terminals to ground is called the.
meg-ohmmeter.
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The first step in starting a chilled water system is to
activate the chilled water circulating system
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Low side pressure, converted to a temp
Evaporator temp
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condensing temp(high side gauge reading converted to a temp) -30*F=
Ambient air
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liquid line temp - condensing temp=
(high side)
Subcooling
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Boiling temp - suction line temp=
(Low side)
Super heat
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(W.C.)(.80)=X+T.W.=
Max bottle weight
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first thing we do on a chiller start up is.
establish water flow through the chiller barrel and the evaporator.
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What must you do 24 hours before start up of the chiller?
Turn on crank case heater.
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What prevents refrigerant migration to the compressor?
- crank case heater.
- Belly band
- internal
 
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What does flow valve do?
detects water flow.
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Witch compressor has an external oil pump?
- centrifugal
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The difference between the oil pump pressure and the suction line pressure of the compressor?
net oil pressure
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For manual pump down witch valve do you have to front seat?
King valve
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The cylinder is moving refrigerant
loaded
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What is meant by Unloading
- As the load drops the pressure drops.
- A pressure control activates a solenoid.
- The suction port is blocked.
- The cylinder can not pump refrigerant.
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one million ohms
one hundred thousand ohms
what must be used to check?
- good compressor
- bad compressor internal grounded
- mego meter
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Large positive displacement chiller?
scroll, reciprocating, screw
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How many pumps in a water cold chiller?
- 2
- condenser pump
- chiller pump
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Screen is located where?
in the tower
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strainer is located where?
between the sump and the pump
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What is used to inspect evaporator tubs for cracks?
- eddy current tester
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Absorption chilled water system start up
- flow must be established
- cooling tower must be within design temperature range
- heat source must be verified
- monitor the purge unit discharge
- check the temp drop across circuit {water flow}
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Lithium bromide [ LiBi ] is what?
absorbent that releases the ammonia into the system
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