THERMAL EXPANSION VALVE (CONT.)
Note position of bulb
Thermal Expansion Valve
on removal and be sure to replace it in the same
Testing Thermal Expansion Valve
operating and supplying cooling
away from sensing bulb and band
screw from band clamps, and
be done while air conditioner is
air conditioner stopped, let the suction
line warm up to ambient temperature.
Remove the sensing bulb from its location against
the suction line, and place it in a container of
ice water or crushed ice (32 F or 0 C).
Do not let liquid refrigerant flood back into the compressor any longer
than 1-2 seconds.
The expansion valve will be wide open during the
following procedure. Excessive flood-back of liquid refrigerant will
damage the compressor.
Start the air conditioner by setting the rotary
selector switch at COOL, and the temperature
control thermostat at maximum DECREASE.
the sensing bulb from the ice water, and hold
it in one hand to warm it while feeling the
If the suction line temperature
drops, the valve is operating properly.
the air conditioner at once, and re-install the
If the temperature of the suction line does
not drop, stop the air conditioner and
replace the expansion valve.