THERMAL EXPANSION VALVE (CONT.)
Thermal Expansion Valve
Remove insulation from a spot on the suction line
near the sensing bulb of the thermal expansion valve
to be adjusted.
Install an accurate thermometer or the probe of a
thermocouple on the bare spot, using a small gob of
thermal mastic, if available, to improve conduct-
Tape the thermometer bulb or thermocouple
junction in position, and cover with insulating
Connect a suitable pressure gauge to the suction
service valve, and open the valve.
Operate the air conditioner in the cooling mode for
about 30 minutes, observing the thermometer or
thermocouple dial to see that the temperature has
When the temperature remains unchanged
for at least two minutes, record the temperature and
Compare the recorded temperature and pressure with
those in Table 5-3.
Each expansion valve should
register higher than the values in the Table by
the following amount.
Thermal expansion valve:
6+1.5 F or 3.3
30.4 + 0.5 F or 16.7 + 0.3 C