WorksheetsJ106A 1
Total questions: 12
Worksheet time: 24mins
When checking system superheat when is the best time to take reading?
When the space temperature is withing 5 degrees of design.
On initial startup of the system.
When the system is satisfied.
The third Sunday after the full moon.
Why is superheat important in a TEV system?
It keeps the temperature of the evaporator up so id doesn't freeze.
It allows the evaporator to operate at its maximum efficiency.
It acts as a margin of safety to prevent compressor damage.
It keeps the compressor lubricated.
What are the three primary forces on a TEV?
Head pressure, suction pressure and valve pressure.
Bulb pressure, evaporator pressure and spring pressure.
Bulb pressure, liquid line pressure and evaporator pressure.
Hot gas pressure, suction pressure and bulb pressure.
What is the only opening force of a TEV?
Spring pressure
Evaporator pressure
Bulb pressure
Inlet pressure
Expansion Devices
Divide the high and low sides of the refrigeration system
Meter the correct amount of refrigerant to the evaporator
Installed in the liquid line at the inlet of the evaporator
all of the above
The following is not an example of an expansion device
Automatic expansion valve (AXV)
Thermostatic expansion valve (TXV)
Fixed bore (capillary tube)
Rotary expansion valve (RXV)
What are the components of a TXV
Sensing bulb and transmission tube
Diaphragm
Needle and Seat
Spring
All of the above
The valve body is made out of:
Aluminum
Brass or Stainless Steel
Copper
Iron
The Diaphragm
Moves the needle in and out of the seat in response to system load changes
Made of thin, flexible stainless steel
Located at the top of the valve
All of the above
The greater the pressure difference across the needle and seat, the _____________ the amount of flow through the valve.
lesser
greater
same
The pressure across the needle and seat does not affect the amount of flow through the valve.
One side of the ______________ gets its pressure from the ________________, and the other side gets its pressure from the evaporator and the spring.
needle and seat
diaphragm and sensing bulb
temperature and pressure
metering device and compressor
SUPERHEAT IS MEASURED ON WHAT SIDE OF THE SYSTEM
RIGHT
LEFT
HIGH
LOW
