FDNY Z51 RMO Set Test Questions And Verified Correct Solutions | Updated

FDNY Z51 RMO Set Test Questions And Verified Correct Solutions | Updated . What can a clogged pump strainer cause? - ANSWER ✔ : A reduction or loss in water flow which will lead to high condenser head pressure. What part of the Refrigeration system is the solenoid valve part of? - ANSWER ✔ : The pum p down cycle (Thermostat - Solenoid Valve - Low Pressure Controller). What is the proper machine start up procedure? - ANSWER ✔ : Check oil, start chilled water pump, start condenser water pump, start tower fans and start up machine. How does a rec iprocating machine cycle compressors on and off? - ANSWER ✔ : Through the use of the low pressure control. What refrigerant has the best Refrigeration effect and highest latent heat? - ANSWER ✔ : Ammonia (R -717) / ASHRE Classification is B2. What is the leaving water temperature of an induced draft cooling tower that is operating efficiently? - ANSWER ✔ : At some temperature between the dry and wet bulb temperature. What could a sudden reduction in the supply flow of the cooling tower water result in? - ANSWER ✔ : An increase in head pressure. How do reciprocating compressor unloaders operate? - ANSWER ✔ : By keeping the compressor suction valves open. Which side of the compressor is R -22 vapor charged into? - ANSWER ✔ : The suction side. What should the percentage of lubricant circulated through a well designed system be? - ANSWER ✔ : Lubricant should not exceed 10%. What is oil foaming in the comp ressor a result of? - ANSWER ✔ : Liquid refrigerant in the crankcase. What is the main reason for installing an oil separator on the discharge line? - ANSWER ✔ : To return oil back to the compressor crank case. What causes the foaming of oil in a reciprocating compressor using the splash system for lubrication? - ANSWER ✔ : A rapid decrease in pressure. What is the purpose of oil in a refrigerant compressor? - ANSWER ✔ : It reduces ware and friction. What is a filter dryer used to remove ? - ANSWER ✔ : Moisture, particles and contaminants. Where in a refrigeration system is the oil separator located? - ANSWER ✔ : On the discharge line as far from the compressor as possible. If a motor has 4 belts and 1 of the 4 belts are worn, ho w many belts should be replaced? - ANSWER ✔ : All of the belts should be replaced. Does a solenoid valve vary or control the flow of refrigerant? - ANSWER ✔ : No. What accessory meters and controls the flow of refrigerant into the evaporator? - ANSWER ✔ : The TEV (Metering Device). What will occur if you use an automatic expansion valve with a variable load? - ANSWER ✔ : You will starve the evaporator. What does an automatic expansion valve do? - ANSWER ✔ : It maintains a constant evap orator pressure. What could cause the evaporator to not respond to the adjustments of the TEV? - ANSWER ✔ : Oil logged on the low side. What can non -condensible's cause? - ANSWER ✔ : High head pressure. When will compressor motor horsepower increase? - ANSWER ✔ : It will increase as the head pressure increases. When will compressor motor horsepower decrease? - ANSWER ✔ : As the suction pressure increases. When using a brine solution in a system what can be used to prevent rusting? - ANSWER ✔ : Di-Chromate Tablets. What would cause a Halide torch flame to turn yellow? - ANSWER ✔ : A clogged sample tube. What is the purpose of having 2 compressors in a cascade system? - ANSWER ✔ : To op erate and very low temperatures and avoid high compression ratio.