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What is cross phasing?
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good design for a hot arid climate
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When troubleshooting an ATC system the system responds when the ambient and in vehicle temp sensors are heated and cooled. However there is no response when the sunload sensor is exposed to a light source. Tech A says that the problem is with the system's programmer. Tech B says it is probably the sunload sensor. Who is correct?
---------- is the amount of carbon left in a sample of oil after it is vaporized, changed from a liquid to a vapor, by boiling it.
When recovering refrigerant from an AC system how long should the tech wait after the recover/recycle unit has been turned off to check residual pressure in the system ?
MIDS contains two types of limit switches. What are they called and what do they do?
Tech A says a special tool is needed to disconnect and connect spring lock fittings. Tech B says when assembling spring lock fittings new O rings lubricated with clean refrigerant oil should be used. Who is right?
List the six transfer paths from the 6-path transfer device.
When IDing an AC system Tech A says that an accumulator located between the evaporator and the compressor is an indication that the system has an orifice tube. Tech B says that when the high side service port fitting is small er than the one on the low side the system uses R134A. Who is right?
Explain the operation of a thermocouple.
The R134A retrofit lable that is placed over the existing R12 reference labor must include all of the following information EXCEPT
During a performance test the air temp at the center outlet duct is warm to slightly cool and the low and high side pressures on the manifold gauge set are both low. All of the following could be the cause of these symptoms EXCEPT:
When using an electronic refrigerant leak detector all of the following should be observed EXCEPT
The Central Chilled Water System uses ____________________ as makeup water. a) Condensate Storage Tank Reject water b) Demineralized Water Storage Tank water c) Service Water d) Potable Water
Does a run capacitor reduce power consumption?
Which signal must be reset in order to close the supply breakers for Atlas-Copco compressors "A" and "B" after a load-shed signal is actuated?
If two capacitors rated at 125 V are connected in series, what is their total voltage?
WMS
enthalpy
Total heat
How many thermocouples are contained in the incore thermocouple system?
What two mechanisms are used to provide snap action?
Alternating current
Hot-humid climatic design responses
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The floor inside a vehicle is wet and there is a slimy film on the windows. Tech A says the heater core is leaking. Tech B says the evaporator case drain plug is clogged. Who is right?
High side pressure in a system is above spec. All of the following can cause this except:
An Atlas-Copco compressor trips. The initiating fault is clear. What manipulation is necessary to make the compressor ready for operation?
Law of electric charges
A compressor clutch will not engage. All of the following could be the cause except
If service air header pressure starts to decrease and continues to decrease, how are the Atlas-Copco compressors started to attempt to bring pressure back to normal?
Tech A says that the AC system can be charged through the high or low side with the engine off. Tech B says the system can be charged thru the low side with the engine running. Who is right?
The ambient temp sensor in an EATC system is being tested. Tech A says the resistance of the sensor should increase as it heats. Tech B says that as the sensor resistance changes the computer reads the change as voltage drop across the sensor. Who is right?
Heat is lost through insulating glass by what process?
When does "over-motoring" occur?
