Exam 24: Expansion Devices

What two pressures control the operation of an automatic expansion valve?

When the evaporator pressure drops, the automatic expansion valve will open to allow more refrigerant to enter the evaporator .

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

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?

As the evaporator load increases, an automatic expansion valve will ____________________ to maintain the suction pressure at the set point .

Explain the recommended method of charging a system with a capillary tube system.

Why should the TXV be adjusted to maintain a low superheat ?

An automatic expansion valve uses a thermal bulb to help control the amount of refrigerant being fed into the evaporator.

The two pressures that push to close a thermostatic expansion valve are the ____________________ pressure and the evaporator pressure.

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

When is an external equalizer-type TXV required?

The TXV sensing bulb is mounted ____.

The step-motor valve uses a small motor to control the valve's port, which in turn controls evaporator superheat.

A capillary tube metering device controls the refrigerant flow by pressure drop .

Pressure entering the compressor that is too high will cause the density of suction gases entering the compressor to increase .

The purpose of a capillary tube is to ____.

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

The solid-state controlled step-motor valve has a temperature sensor, or thermistor, as one of its inputs .

Balanced port TXVs are used to ____ ambient temperatures .

The TXV maintains a constant ____________________ in the evaporator .