CRST Installation & Maintenance Practices 4

Question 1

Which tool is used to measure the depth of a vacuum during system evacuation?

Accepted Answer

Micron gauge (electronic vacuum gauge)

Answer

An electronic micron gauge accurately measures deep vacuums in microns of mercury, which standard manifold gauges cannot resolve.

Question 2

A walk-in freezer door gasket is worn and not sealing properly. Besides temperature loss, what additional problem can result?

Accepted Answer

Excessive frost buildup on evaporator due to warm, moist air infiltration

Answer

Warm, humid air entering through a faulty door gasket increases the moisture load on the evaporator, causing excessive frost accumulation and longer defrost cycles.

Question 3

What is the recommended torque method for tightening flare fittings to avoid over-tightening and cracking the flare?

Accepted Answer

Use a calibrated torque wrench to the manufacturer's specification

Answer

Manufacturer torque specifications applied with a calibrated torque wrench prevent both under-tightening (leaks) and over-tightening (cracked flares).

Question 4

During installation of a refrigeration system, the technician discovers the power supply voltage is 208V but the unit is rated for 230V. What should be done?

Accepted Answer

Install a step-up transformer or notify the customer that voltage must be corrected before startup

Answer

Operating a 230V-rated unit on 208V causes low-voltage conditions that can overheat motors and void the warranty; the supply voltage must be corrected.

Question 5

What is the function of a liquid line solenoid valve in a refrigeration system?

Accepted Answer

Pump down the evaporator when the system shuts off to prevent liquid migration

Answer

A liquid line solenoid valve closes on shutdown to pump down the low side, preventing liquid refrigerant from migrating to the compressor crankcase.

(CRST) Certified Refrigeration Service Technician Practice Test

(CRST) Certified Refrigeration Service Technician Practice Test

CRST Installation & Maintenance Practices 4