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44 Cards in this Set
- Front
- Back
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IN A HORIZONTAN SHELL AND TUBE CONDENSER
A-THE WATER IS IN THE- B-THE REFRIGERANT IS IN THE- |
A-TUBE
B-SHELL |
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THE REFRIGERANT ENTERS THE CONDENSER AS -A__________AND
EXITS AS B_________ |
A-HIGH PREASURE VAPOR
B-HIGH PREASURE LIQUID |
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THE FUNCTIONS PERFORMED BY A MEETERING DEVICE ARE ?
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1-CONTROL THE FLOW OF LOW PREASURE LIQUID TO THE EVAPORATOR
2-SEPARATE THE HIGH SIDE OF THE SYSTEM FROM THE LOW SIDE 3-REDUCE THE REFRIGERANT PREASURE |
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1 CONDENSING TON =
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250 BTU PER MINUTE
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ORIFICE PLATE ?
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METERING DEVICE ON A CENTRIFUGAL CHILER
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WHAT IS TH FUNCTION OF A PURGER
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TO RID A REFRIGERATION SYSTEM OF NON CONDENSABLE GASES
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in a cooling tower,for each pound of water that evaporates,how much heat is rejected?
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970 BTU'S
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AT A GIVEN TEMPERATURE,THE RATIO OF ACTUAL VAPOR IN THE ATMOSPHERE TO THE SATURATION PREASURE IS CALLED
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RELATIVE HUMIDITY
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If the eliminator fins located below the fan of a enduced-draft cooling tower become cloged what will take place?
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cooling water temperature increases
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a indication that a systems cooling tower is not operating as designed
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high head preasure
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witch type of cooling tower or evaporative condencer has a fan at the air inlet
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forced draft
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why are wet bulb readings generally lower than dry bulb readings
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the cooling efect of evaporation
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an induced draft cooling tower is one in wich the air?
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is pulled through the tower
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improperly treated cooling tower water may result in
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growth of bacteria and rusty pipes
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in a induced draft cooling tower wich is operating efficiently the leaving water temperature is generaly
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between the prevaling dry bulb and wet bulb temperature
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the reading of a sling pschrometer are in units of
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temperature
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in cooling towers chemicals are used to?
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inhibit rust
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a sample of water taken from a cooling tower is fownd to have a ph of 7.8 it can be said that it is
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slightly al kaline
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a cooling tower should be maintained at a PH value most nearly ?
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8
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the main reason why cooling towers are provided with a constant water bleed off is to
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to prevent a hi build up of solid concentration in the water
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if the measured wet bulb and dry buld temperatures have equivalent readings what statement can be made about the conditions of the air ?
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the air is saturated with moisture
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heat is rejected from a coolig tower when the temperature of the cooling water is ?
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higher than the dry bulb temperature
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on a humid day when the head preasure is higher than narmal the RMO should ?
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turn aditional tower fans on
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a sling thermometer is used to?
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dry and wet bulb temperatures
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on a day the dry bulb stays the same but the wet temperature decreases by 5deg what should the operator observe
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lower cooling water temperature being returned
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a refrigeration system includes a forced draft cooling tower,an economizer and chilled water as the cooling medium,heat is removed from the building is finaly rejected as?
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latent heat of vaporization in the cooling tower
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what would cause a condenser waterpump to cavitate?
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a faulty cooling tower make-up water valve
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the start-up sequence for a receprocating machine should be as follows ?
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start cooling tower fan ,start chilled water and condencer water pumps,check oil level,turn on chillers
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if the condencer cooling water were to return to a condenser at a temperature of 105 deg what might be rong ?
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the cooling fans may be off
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what funtion do enviromental stabilizers perform inside of a cooling tower
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adjust chemical solutions to inhibit corrosion
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the most usefull question to consider in making a decition as to use a roof top unit is ?
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will the struture suport the weight of the unit
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most factory assembled cooling towers are constructed of ?
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galvanized steel
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an induce draft cooling tower the lowest leaving water temperature will be obtained when ?
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dry bulb is higher than the wet bulb temperature
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how would you describe the condition of the air when the dry and wet bulb temperature is equal ?
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100% relative humidity
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a problem associated with static electricity increase when th ambient air is?
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dry
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a forced draft cooling tower is used to cool condencer water .the lowest temperature that the leaving water can be reduced to is ?
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sligtly higher than the wet bulb teperature
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what would cause a decrease in flow rate on a pump operating at normal preasure ?
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a Dirty Strainer
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a system with two condenser pumps has a total preasure drop of 40 psi.with only one pump running what will be the system preasure drop ?
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40 psi
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what would cause the condenser water temperature to rise when the pump is running ?
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a cloged strainer
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whitch valve has he least amount of preasure drop ?
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gate valve
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how are centrifugal pumps rated ?
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G.P.M gallons per minute
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proper procedure to turn on a (condenser)pump is suction valve completely open and the discharge valve side
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closed until the motor reaches its full RPM
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a device that is installed in the chilled water piping to ensure that the chilled water pump is operating is called ?
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a flow swith
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a condenser water pump has two copper tubes coming out of the top of the pump volute.to the pump shaft,what are the purpose of these tubes
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to cool the shaft and bearings
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