16. ACR-104 UNIT24 END OF UNIT

The following is a function of an expansion device: ____.

• produce a reduction in the pressure on the liquid refrigerant

• regulate the flow of refrigerant into the evaporator

• lower the boiling point of the refrigerant far enough below the temperature of the load to get the needed heat transfer rate

• All of the above.

A thermostatic expansion valve meters refrigerant flow to the evaporator based on the ____.

• rate of liquid vaporization

• evaporator suction line superheat

• external equalizer pressure

• All of the above.

If a thermostatic expansion valve's thermal bulb came loose from the suction line at the outlet of the evaporator, which of the following could result?

• The bulb pressure would increase and the thermostatic expansion valve would open.

• The superheat in the evaporator would decrease.

• The evaporating pressure and the compressor’s suction pressure would increase.

• All of the above are correct.

The TXV sensing bulb is mounted ____.

• on the liquid line between the condenser and the TXV

• at the inlet to the condenser

• on the suction line between the evaporator and the compressor

• on the compressor discharge line

The cross liquid charge bulb at the TXV contains fluid that ____.

• has similar characteristics to the system fluid to prevent liquid refrigerant from entering the suction line

• has different characteristics from the system fluid

• causes the valve to stay open during the off cycle

• follows the system’s pressure-temperature relationship

When the load on the evaporator increases, the TXV ____.

• increases the flow of refrigerant

• decreases the flow of refrigerant

• maintains constant head pressure

• decreases the pressure drop across the

If the thermal bulb assembly develops a leak, what will occur?

• All of the system's refrigerant will leak out.

• The bulb pressure will reduce and the valve will close.

• The valve will open to allow more refrigerant to flow.

• It will have no effect on system operation.

The purpose of an external equalizer in a TXV is to ____.

• compensate for excessive evaporator pressure drop

• allow system to equalize faster

• prevent the expansion valve from frosting up

• allow refrigerant to expand in the compressor

Balanced port TXVs are used to ____ ambient temperatures.

• feed refrigerant at a normal rate with low

• feed refrigerant at a normal rate with high

• stop refrigerant flow with high

• stop refrigerant flow with low

The pressure-limiting TXV ____.

• allows the compressor to operate at low condenser entering air temperatures

• shuts off the condenser fan during hot pull down

• maintains the full refrigerant flow rate during a hot pulldown

• keeps the suction pressure to the compressor down during a hot pulldown