Commercial Refrigeration
Certification Study Questions with
Complete Solutions
Approximately how much Air flow is required across an air cooled condenser? -
ANSWER - 750-1000 CFM Per Ton of Cooling Capacity
A sling psycrometer is used to measure.....? - ANSWER - Wet and dry bulb
temperature
The capacity of an evaporative condenser depends on....? - ANSWER - The Entering
Air Wet Bulb Temperature
Hot Gas Bypass refers to....? - ANSWER - All of Above (Preventing low suction
pressure, Providing Capacity Control, Preventing Compressor short Cycling.)
A compressor is operating with a discharge pressure of 185.3 PSIG and a suction
pressure of 25.3 PSIG. The compression ratio (Pumping Ratio) is.....? - ANSWER - 5:1
Wet bulb depression is.....? - ANSWER - The difference between Wet bulb and Dry
Bulb Temperatures
A compressor net oil pressure is determined by.....? - ANSWER - Oil pump discharge
pressure minus the Suction Pressure
Some compressors are fitted with an unloading device to provide variable capacity.
Variable Capacity is necessary to......? - ANSWER - All of above (Prevent Undesirably
low evaporator pressures, Prevent evaporator coil frost, & Prevent Compressor short
Cycling)
Refrigerant in the suction line should be slightly superheated in order to.......? -
ANSWER - Insure liquid refrigerant does not enter the Compressor
, A decrease in water flow, when using a water cooled condenser....? - ANSWER -
Increase the power consumtion of the compressor
If a TEV sensing bulb lost its charge, what effect would this moment have on the AC
system? - ANSWER - Both A and B(It would cause high side pressure to increase and
cause low side to decrease)
What is the purpose of the distributor....? - ANSWER - It evenly feeds refrigerant to
the evpaorator
High compressor operating temperatures can be caused by.....? - ANSWER - All of
Above (Low Volumetric Efficiency, Low Suction Pressures, and High Compression
Ratio)
The clearance space in a reciprocating compressor....? - ANSWER - Has an effect on
compressor capacity
The amount of heat absorbed in the evaporator is equal to....? - ANSWER - The heat
in the conditioned space
Approximately how much airflow is required across the evaporator per ton of cooling
capacity? - ANSWER - 350-400 CFM Per Ton
The most reliable and safest method of field charging a system is.....? - ANSWER - To
charge by weight according to manufacturer specifications
On split system installations, the suction line should be pitched towards the
compressor at least....? - ANSWER - One inch per 10 feet (1 inch/10ft)
Polyolester oils---? - ANSWER - All of Above (hold moisture tightly, so more
evacuation time may be necessary, Have similar lubricity and miscibility
characteristics as mineral oil, and Absorb atmospheric moisture more easily than
mineral oil)
Certification Study Questions with
Complete Solutions
Approximately how much Air flow is required across an air cooled condenser? -
ANSWER - 750-1000 CFM Per Ton of Cooling Capacity
A sling psycrometer is used to measure.....? - ANSWER - Wet and dry bulb
temperature
The capacity of an evaporative condenser depends on....? - ANSWER - The Entering
Air Wet Bulb Temperature
Hot Gas Bypass refers to....? - ANSWER - All of Above (Preventing low suction
pressure, Providing Capacity Control, Preventing Compressor short Cycling.)
A compressor is operating with a discharge pressure of 185.3 PSIG and a suction
pressure of 25.3 PSIG. The compression ratio (Pumping Ratio) is.....? - ANSWER - 5:1
Wet bulb depression is.....? - ANSWER - The difference between Wet bulb and Dry
Bulb Temperatures
A compressor net oil pressure is determined by.....? - ANSWER - Oil pump discharge
pressure minus the Suction Pressure
Some compressors are fitted with an unloading device to provide variable capacity.
Variable Capacity is necessary to......? - ANSWER - All of above (Prevent Undesirably
low evaporator pressures, Prevent evaporator coil frost, & Prevent Compressor short
Cycling)
Refrigerant in the suction line should be slightly superheated in order to.......? -
ANSWER - Insure liquid refrigerant does not enter the Compressor
, A decrease in water flow, when using a water cooled condenser....? - ANSWER -
Increase the power consumtion of the compressor
If a TEV sensing bulb lost its charge, what effect would this moment have on the AC
system? - ANSWER - Both A and B(It would cause high side pressure to increase and
cause low side to decrease)
What is the purpose of the distributor....? - ANSWER - It evenly feeds refrigerant to
the evpaorator
High compressor operating temperatures can be caused by.....? - ANSWER - All of
Above (Low Volumetric Efficiency, Low Suction Pressures, and High Compression
Ratio)
The clearance space in a reciprocating compressor....? - ANSWER - Has an effect on
compressor capacity
The amount of heat absorbed in the evaporator is equal to....? - ANSWER - The heat
in the conditioned space
Approximately how much airflow is required across the evaporator per ton of cooling
capacity? - ANSWER - 350-400 CFM Per Ton
The most reliable and safest method of field charging a system is.....? - ANSWER - To
charge by weight according to manufacturer specifications
On split system installations, the suction line should be pitched towards the
compressor at least....? - ANSWER - One inch per 10 feet (1 inch/10ft)
Polyolester oils---? - ANSWER - All of Above (hold moisture tightly, so more
evacuation time may be necessary, Have similar lubricity and miscibility
characteristics as mineral oil, and Absorb atmospheric moisture more easily than
mineral oil)
