MCQ in Refrigeration Engineering Part 6 | ME Board Exam

(Last Updated On: December 27, 2020)

This is the Multiple Choice Questions Part 6 of the Series in Refrigeration Engineering as one of the Mechanical Engineering topic. In Preparation for the ME Board Exam make sure to expose yourself and familiarize in each and every questions compiled here taken from various sources including but not limited to past Board Exam Questions in Mechanical Engineering field, Mechanical Engineering Books, Journals and other ME References. I assume you are looking for a reviewer that will help you achieve your goal to become a License Mechanical Engineer very soon. Yes, you are in the right place to make your dream come true. Make sure to familiarize each and every questions to increase the chance of passing the Mechanical Board Examination.

MCQ Topic Outline included in ME Board Exam Syllabi

• MCQ in Principles of Different Refrigeration Systems
• MCQ in Determination of Cooling Loads
• MCQ in Basic Design of Ice Plants, Cold Storage and Skating Rinks
• MCQ in Instrumentation and Controls

Continue Practice Exam Test Questions Part 6 of the Series

⇐ MCQ in Refrigeration Engineering Part 5 | ME Board Exam

Choose the letter of the best answer in each questions.

251. Which of the following types of valve are not used for suction or discharge?

A. Gate

B. Diaphragm

C. Metallic

D. ring

252. What usually happened if brine has a high specific gravity?

A. It will freeze

B. It will crystallize

C. Nothing will happen

D. It will solidify

253. When does the refrigerant gives-up heat?

A. When it evaporates

B. When it condenses

C. When it vaporizes

D. When it boils

254. The thermostatic expansion valve is designed to maintain constant_________

A. Pressure

B. Flow

C. Temperature

D. superheat

255. A reactor plate is essential to the operation of a _________.

A. Thermostatic valve

B. Halide torch

C. Solenoid bulb

D. None of these

256. The greatest decrease in the temperature of the refrigerant is at the _______.

A. Condenser

B. Expansion valve

C. Evaporator

D. receiver

257. The temperature of the refrigerant is highest just before it enters the:

A. Receiver

B. Evaporator

C. Condenser

D. King valve

258. A hot suction line could be caused by:

A. Insufficient refrigerant

B. Excess refrigerant

C. Excess cooling water

D. Insufficient cooling water

259. Which of the following devices will prevent the relief valve from opening in the event of excessive pressure?

A. Water failure switch

B. High-pressure cutout switch

C. Low-pressure cutout switch

D. Any of these

260. Which of the following would cause the suction switch to remain open?

A. Insufficient spring tension

B. Too much spring tension

C. Bellows broken or jammed

D. A or B

261. Which of the following would not cause high head pressure?

A. Air in system

B. Overcharge of refrigerant

C. Circulating water too warm

D. Liquid freezing back

262. A “cold diffuser” is a:

A. Type of condenser

B. Special valve used as a bypass

C. Type of evaporator

D. None of these

263. Which do you think is the effect of “subcooling”?

A. It causes flooding back to the compressor

B. It reduces the horsepower per ton of refrigeration

C. It increases the compression ratio

D. It increases the horsepower per ton of refrigeration

264. Subcooling is to:

A. Cool the evaporator below its normal temperature

B. Cool the liquid before it enters the evaporator

C. Cool a liquid at constant pressure to a temperature lower than its condensing temperature

D. Cool the refrigerant gas before it enters the receiver

265. When figuring compression ratio, the ratio will increase with a ________.

A. Lower suction pressure

B. Higher suction pressure

C. Higher discharge pressure

D. A and C

266. Copper tubing is used in Freon system because :

A. it has less internal resistance

B. it is cheaper

C. it is easier to check leaks

D. iron corrodes

267. The cooling water regulator is actuated by

A. an electric relay

B. pressure of the refrigerant

C. temperature of the refrigerant

D. none of these

268. If there is a 20°F temperature drop between the temperature corresponding to the pressure at the compressor discharge and the condenser outlet, one should :

A. decrease the amount of circulating water

B. increase the amount of circulating water

C. purge the system

D. none of these

269. If refrigeration controls were constructed with the little or no differential, the :

A. compressor would short cycle

B. icebox would get too cold

C. icebox would get too warm

D. refrigerant would be subcooled

270. What is the use of back pressure regulating valve?

A. controls the evaporator temperature by throttling the flow of liquid refrigerant

B. maintains a fixed pressure in the evaporator coils

C. controls the flow of circulating water in the condenser tubes

D. controls the temperature in the evaporator coils

271. If the thermal bulb becomes loose on the evaporator coils, it will cause ________.

A. an electrical short

B. flooding back of the refrigerant

C. improper operation of expansion valve

D. any of these

272. External frost on inlet of expansion valve indicates:

A. expansion valve plugged or dirty

B. head pressure too high

C. refrigerating compartment too cold

D. air in system

273. Subcooling of the refrigerant results in :

A. less circulating water needed

B. effect of refrigerant increased

C. liquid less likely to vaporize

D. B and C

274. Which of the following is the reason when the crankcase is cooler than the suction line?

A. too much refrigerant

B. insufficient refrigerant

C. expansion valve open too wide

D. suction valve leaking

275. If the outlet of the thermostatic valve is warmer than the inlet, it indicates

A. flooding back

B. thermostatic valve working properly

C. thermostatic valve not working properly

D. solenoid valve not working properly

276. High temperature of cylinder heads and crankcase is caused by:

A. insufficient refrigerant

B. too much refrigerant

C. high head pressure

D. non condensable gases

277. Frost on the high-pressure side of a thermostatic expansion valve would probably be caused by

A. high head pressure

B. dirty expansion valve

C. refrigerator box too cold

D. loss of circulating water to condenser

278. A Freon – 12 gage shows pressure and _______.

A. superheat temperature

B. saturation temperature

C. back pressure

D. vacuum

279. Moisture in a system will cause a :

A. faulty expansion valve

B. high suction pressure

C. high suction temperature

D. low discharge temperature

280. Which of the following is not essential to a centrifugal type of compressor system?

A. evaporator

B. distiller

C. condenser

D. expansion valve

281. A scale trap in Freon system will be found on the:

A. receiver

B. discharge side

C. suction side

D. condenser

282. Which of the following would cause expansion valve failure?

A. dirt in the valve

B. moisture in the system

C. bulb in icebox ruptured

D. any of these

283. Two compressor should not be run in parallel because:

A. there is a possibility of losing oil

B. it will give over-capacity

C. it is nit efficient

D. A or B

284. The process that takes place in the evaporator is called

A. transfer of the latent heat of vaporation

B. absorption of the latent heat of vaporization

C. absorption of the latent heat of fusion

D. transfer of the latent heat of fusion

285. What is the use of the low – water cutout switch?

A. recirculates the cooling water when there is too much refrigerant in the condenser

B. stops the compressor when there is no refrigerant running to the evaporator

C. stops the flow of the refrigerant when the condenser temperature is too low

D. stops the compressor when there is insufficient cooling water

286. The high-pressure cutout switch :

A. stops the flow of refrigerant when condenser pressure is too high

B. recirculates the refrigerant through the compressor under emergency conditions

C. stops flow of water to condenser when there is no refrigerant passing through

D. stops compressor when head pressure is too high

287. Zinc rods are found in the :

A. gas side of the condenser

B. salt water side of the condenser

C. evaporator are

D. compressor crankcase

288. Which of the following is not essential to a compression refrigeration system?

A. a receiver

B. a condenser

C. an evaporator

D. a dehydrator

289. What is the effect if the refrigerant is removed from the system too fast?

A. it may flood the evaporator

B. it may “freeze-up” the condenser

C. it will lower the icebox temperature

D. none of these

290. Closing the solenoid valve stops the compressor through the :

A. high – pressure cutout switch

B. low water – pressure cutout switch

C. low – pressure cutout switch

D. high water – pressure cutout switch

291. A precooler, if used, is located between the :

A. expansion valve and evaporator

B. compressor and condenser

C. evaporator and compressor

D. condenser and expansion valve

292. When the outlet temperature at the evaporator exceeds the inlet temperature, the condition is known as :

A. superheating

B. desuperheating

C. dehydrating

D. saturating

293. The purpose of providing hot-gas defrosting facilities :

A. defrosting without raising compartment temperature above 32°F

B. thawing frozen coils

C. defrosting automatically

D. B or C

294. The suction control switch on the compressor is a

A. thermal element

B. thermostat

C. pressure element

D. bellows

295. With one machine serving several compartment, when one compartment reaches the desired temperature, the temperature in that compartment is maintained by :

A. the expansion valve

B. the solenoid valve

C. the back-pressure valve

D. any of these

296. The back-pressure regulating valve:

A. controls the water flow through the condenser

B. stops the flow of liquid refrigerant when temperature drops in evaporator

C. maintains a fixed pressure in the evaporator coils

D. none of these

297. Faulty F – 12 compressor valves will be indicated by:

A. low head pressure-high suction pressure

B. compressor running continuously

C. gradual or sudden decrease in capacity

D. all of these

298. How were tubing joints done?

A. brazed

B. welded

C. screwed

D. silver soldered

299. When starting a refrigerating unit, be sure the water side of the condenser is _______.

A. secured

B. bypassed

C. vented

D. B and C

300. The water regulating valve is operated by the

A. compressor discharge pressure

B. compressor discharge temperature

C. compressor suction pressure

D. none of these