CRST Refrigeration Systems & Components 4

Question 1

What does a high suction superheat combined with normal or low head pressure indicate in a refrigeration system?

Accepted Answer

Low refrigerant charge or metering device starving the evaporator

Answer

High superheat with normal or low head pressure points to insufficient refrigerant flow through the evaporator, typically from a low charge or restricted metering device.

Question 2

What is the purpose of a discharge muffler in a reciprocating compressor system?

Accepted Answer

Dampen pulsations in the discharge line

Answer

A discharge muffler attenuates pressure pulsations caused by the reciprocating action of the compressor pistons, reducing vibration and noise.

Question 3

When sizing a liquid line, which factor is MOST critical to avoid flash gas formation?

Accepted Answer

Ensuring adequate subcooling and minimal pressure drop

Answer

Adequate subcooling provides a safety margin against pressure drop-induced flash gas, which would starve the metering device and reduce capacity.

Question 4

A technician measures compressor amperage at 110% of nameplate rating. What is the most likely cause?

Accepted Answer

High head pressure due to condenser fouling or airflow restriction

Answer

High head pressure forces the compressor to work harder against greater discharge pressure, drawing excessive amperage.

Question 5

What is the role of a desuperheater in a refrigeration system?

Accepted Answer

Extract heat from hot discharge gas for water heating

Answer

A desuperheater is a heat exchanger that recovers heat from superheated discharge gas, commonly used to preheat domestic hot water.

(CRST) Certified Refrigeration Service Technician Practice Test

(CRST) Certified Refrigeration Service Technician Practice Test

CRST Refrigeration Systems & Components 4