RMO REVIEW 3 Flashcards
- Liquid level gauge glasses (except bull’s eye type) shall have shut off valves:
A. Manual only
B. Automatic only
C. Valves not needed
D. Manual and automatic
D. Manual and automatic
- Convert 20 psig to “HG Absolute
A. 30
B. 70
C. 80
D. 90
B. 70
- Why can’t you use a flare fitting ¾” or larger?
A. Can’t flare that large
B. Can’t tighten to get a good seal
C. Against the law
D. Easier to sweat
B. Can’t tighten to get a good seal
- For systems containing 50 lbs of refrigerant, stop valves are required:
A. At inlet of each compressor
B. At inlet of liquid receiver
C. Before and after sight glass
D. Not required
A. At inlet of each compressor
- The amount of ventilation for refrigerant removal purposes in a machine room shall be sized according to:
A. Total amount of refrigerants in unit
B. Total amount of the most flammable refrigerant
C. Total of the refrigerant in the largest machine
D. Total amount of refrigerant in units and stored in machine room
C. Total of the refrigerant in the largest machine
- The outlet from a fan or air duct used to ventilate refrigerants must be at least _____ feet from any air intake or exhaust or any opening in an adjoining building.
A. 5
B. 10
C. 20
D. 50
B. 10
- You are a RMO and you want to work on the machine’s pressure relief valve on a dual pressure relief valve system. What valve would you install to work on one pressure relief valve while allowing the other to operate in the system?
A. Gate valve
B. Butterfly valve or plug valve
C. Two-way valve
D. Three-way valve
D. Maintain a constant condenser pressure
- You are an RMO and you start the machine and the machine doesn’t start. Your fuses, circuit breakers and electrical components are all good. What would you check next?
A. Sight glass
B. Thermostat
C. Low pressure cut-out, pressure switch
D. Refrigerant charge
C. Low pressure cut-out, pressure switch
- What is superheated vapor?
A. Very high temperature gas mixed with fluid
B. Dry vapor
C. Dry vapor at its boiling point
D. Dry vapor above its boiling point
D. Dry vapor above its boiling point
- How does a solenoid valve work?
A. Open a plunger and allow refrigerant in
B. Open a spring valve and allow refrigerant in
C. Manually opens and allow refrigerant in
D. Manually closes and prevents refrigerant in
A. Open a plunger and allow refrigerant in
- A water regulating valve is connected to the outlet of the condenser. What is this valve designed to do?
A. Maintain a condenser pressure within pre-set limits
B. Maintain a constant water pressure
C. Maintain a constant water temperature
D. Maintain a constant condenser pressure
A. Maintain a condenser pressure within pre-set limits
- You are an RMO and you start the machine and the machine doesn’t start. Your fuses, circuit breakers and electrical components are all good. What would you check next?
A. Sight glass
B. Thermostat
C. Low pressure cut-out, pressure switch
D. Refrigerant charge
C. Low pressure cut-out, pressure switch
12. When a thermostatic expansion valve is operating properly, the end of the coil will contain: A. Saturated vapor B. Superheated vapor C. Low temperature liquid D. Hot vapor
B. Superheated vapor
- A compressor that uses a shaft with a mechanical seal. What is the valve plate made of?
A. Metal / carbon
B. Plastic
C. Rubber
D. Silicon
A. Metal / carbon
- On a valve plate, where are the suction and discharge valves located?
A. Suction on top, discharge on the bottom
B. Suction on bottom, discharge on top
C. Suction and discharge on top
D. Suction and discharge on bottom
B. Suction on bottom, discharge on top
- What controls a solenoid valve motor?
A. Watts
B. Volts
C. Horsepower
D. Amps
B. Volts
- Why is glycol a better brine than sodium chloride?
A. More conductive
B. Cost less
C. No corrosion
D. Higher freezing point
C. No corrosion
- What does a filter drier do?
A. Remove particles
B. Remove moisture
C. Remove acid
D. All of the above
D. All of the above
- How does a reciprocating compressor vary capacity?
A. Cylinder unloaders
B. Hot gas bypass
C. Motor speed variation
D. All of the above
A. Cylinder unloaders
- A safety head is a:
A. Pressure relief valve inside the compressor
B. Pressure relief valve on top of the head
C. Valve plate being held down with a spring
D. High side pressure in system below design pressure
C. Valve plate being held down with a spring
- When water turns to ice, what took place?
A. Superheat
B. Heat of fusion
C. Heat of evaporation
D. Sub-cooling
B. Heat of fusion
- Why do cascade systems use two compressors?
A. Split the cooling load
B. To accommodate high head pressure
C. To increase the compression ratio
D. To negate the effects of high compression ratio
A. Split the cooling load
- If the refrigeration oil is measured to have a viscosity and the viscosity number is low, what does that mean?
A. Doesn’t flow
B. Flows easily, smoothly
C. Flow is slow
D. Restricted flow
B. Flows easily, smoothly
- If you need to add another pump online, how do you do it?
A. Open the suction side valve and put the discharge valve in the throttle position
B. Open suction and close discharge
C. Close suction and open discharge
D. Open suction and slowly fully open discharge
A. Open the suction side valve and put the discharge valve in the throttle position
- The automatic expansion valve (AEV) is used instead of a TEV. It maintains a constant pressure on the evaporator. Another function it has is:
A. Works well on variable loads
B. Allows refrigerant on rise in pressure
C. Needs temperature control to protect the evaporator from freezing up from cold water
D. On water type evaporator, freezing will not occur
D. On water type evaporator, freezing will not occur
- The pressure of water going through a shell and tube condenser is proportional to the square of its velocity. If it velocity originally was 40 and its original pressure was halved, what would be the velocity be?
A. 40
B. 30
C. 20
D. 10
D. 10
- If 10 BTU’s is transferred to 10 lbs of water, the increase in temperature is closest to:
A. 10 F
B. 10 C
C. 1 F
D. 1 C
C. 1 F
- What is the order of components on the liquid line of a reciprocation system from the king valve?
A. Filter drier, solenoid valve, sight glass, TEV to evaporator
B. Solenoid valve, filter drier, sight glass, TEV to evaporator
C. Sight glass, solenoid, sight glass, filter drier, TEV to evaporator
D. TEV, sight glass, solenoid, filter drier to evaporator
A. Filter drier, solenoid valve, sight glass, TEV to evaporator
- The unit used to measure the amount of electrons flowing past a certain point in an electrical circuit is called:
A. Ohm B. Ampere C. Volt D. Watt E. None of the above
B. Ampere
- Before using a voltmeter, the technician should always:
A. Zero the ohm adjustment
B. Touch the two leads together to ensure continuity
C. Set the range selector to a setting higher than the voltage expected
D. Turn off the power
E. None of the above
C. Set the range selector to a setting higher than the voltage expected
- As an RMO you enter a system of a reciprocating refrigeration unit. This system has 150 lbs of refrigerant charge, you would expect to find stop valves:
A. On the inlet supply and the discharge line
B. Before and after the liquid bull’s eye sight glass
C. On the inlet line of the condenser receiver
D. On the inlet to each compressor
A. On the inlet supply and the discharge line
- Regardless of the safety classification of the refrigerant in use, in the event of refrigerant escape, the RMO should be aware of:
A. A refrigerant fire
B. Refrigerant poisoning
C. Oxygen deprivation
D. Atmospheric superheating
C. Oxygen deprivation
- When you are finished leak testing with nitrogen and R-22, then the next step would be to:
A. Vent refrigerant and nitrogen to the open air
B. Remove refrigerant and nitrogen at the recovery machine
C. Add refrigerant
D. Add refrigerant if needed and put system back on line
A. Vent refrigerant and nitrogen to the open air
- When oil leaves the sump in a centrifugal refrigeration system, where does the oil go?
A. Travels with the refrigerant to cool the refrigeration system
B. Travels back to the oil sump
C. Is compatible with the refrigerant and will travel through the system and return to the oil sump
D. Travels through the system and is drained out of the sump by a petcock valve
B. Travels back to the oil sump
- The type of refrigerant in the feeler bulb on a system would be:
A. The same as the refrigerant in the system
B. Highly flammable / highly toxic
C. Non-flammable / non toxic
D. Would be a different type of refrigerant than the one in the system
C. Non-flammable / non toxic
- What is the pressure of R-22 at 41 F?
A. 38 psig
B. 70 psig
C. 18.5” Hg
D. 81
B. 70 psig
- Aside from venting refrigerant from your hose connection, the only other time you may discharge refrigerant would be:
A. When a fire department engineer is present
B. Never
C. After the fire department engineer leaves the room
D. To check if there is any refrigerant in the system
B. Never
- After the compressor you have the oil separator, which:
A. In general returns the oil to the crankcase
B. Filters the oil and returns the oil to the crankcase
C. Removes the water from the oil
D. Distributes oil to the evaporator
A. In general returns the oil to the crankcase
- An open type compressor is keeping the refrigerant from escaping by tightening a seal made of:
A. rubber
B. graphite loaded fiber
C. carbon and metal
D. fortified plastic
C. carbon and metal
- How many BTU’s are absorbed by a 5 tons of ice?
A. 188,000
B. 2,200,000
C. 1,440,000
D. None
C. 1,440,000