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4.14 THERMOSTATIC EXPANSION VALVE
1.
Thermostatic element
2.
Interchangeable orifice assembly
3.
Valve body
4.
Superheating setting spindle
The thermal expansion valve is an automatic device
that maintains constant superheat of the refrigerant
gas leaving the evaporator regardless of suction
pressure. The valve functions are: (a) automatic
response of refrigerant flow to match the evaporator
load and (b) prevention of liquid refrigerant entering
the compressor. Unless the valve is defective, it
seldom requires any maintenance.
It is critical that superheat is correct after installation
or repair. Following the steps in 4.14.1 will ensure
that the unit is now cooling correctly
NOTE:
Perform all refrigeration tests first to ensure
the correct amount of refrigerant and all refrigeration
components are working correctly before any repairs
or adjustments of the TXV.
The Thermal Expansion valve is mounted on liquid line just
next to the evaporator and the TXV bulb is placed on the
evaporator port outlet.
Figure 20 - Expansion Valve Components
Figure 21- TXV location Drawing
