RSES Expansion Devices 5

Question 1

A low-side float valve opens when the liquid level in the evaporator:

Accepted Answer

Falls below the setpoint

Answer

When liquid level drops, the float falls and opens the valve to admit more refrigerant, maintaining the correct flooded level.

Question 2

Which factor primarily determines the refrigerant flow capacity of a capillary tube?

Accepted Answer

Tube length and inside diameter

Answer

Capillary tube flow capacity is determined by its length and inside diameter, with shorter/larger diameter tubes passing more refrigerant.

Question 3

An electronic expansion valve (EEV) in a variable refrigerant flow (VRF) system is typically controlled by:

Accepted Answer

A microprocessor receiving inputs from multiple sensors

Answer

EEVs in VRF systems are controlled by microprocessors using inputs such as suction superheat, coil temperature, and load demand for optimal performance.

Question 4

When replacing a TXV, which specification is most critical to match?

Accepted Answer

Refrigerant type, capacity rating, and evaporator temperature range

Answer

The replacement TXV must be rated for the same refrigerant, system capacity, and operating temperature range to ensure proper performance.

Question 5

What symptom would a refrigeration technician observe if the TXV sensing bulb loses its refrigerant charge?

Accepted Answer

TXV closes fully, starving the evaporator

Answer

Without bulb pressure as the opening force, the spring pressure keeps the TXV closed, starving the evaporator and causing high superheat.

(RSES) Refrigeration Service Engineers Society Certification Practice Test

(RSES) Refrigeration Service Engineers Society Certification Practice Test

RSES Expansion Devices 5