Missouri (St. Louis County) Commercial HVAC
Servicer_Installer - 588-MO-SL Contractor Exam
ACTUAL VERIFIED QUESTIONS AND ANSWERS
LATEST UPDATE.pdf
When computing heat leakage for a building, the U-value
for most types of construction can be obtained from
reference books. The unit of measure for U-value is
expressed in __________? - Answer-Btu/sq-ft/deg.F/Hr
Absolute zero temperature is the temperature at which all
molecular motion ceases at approximately
_______degrees Fahrenheit. - Answer--460 degrees F
What would be the calculated resistance of a circuits load,
given that the load draws a total current of 20 amperes,
and the circuit source operating voltage is 240 VAC? -
Answer-12.0
A contractor is working with auxiliary drain pans in a
secondary drain system for an air conditioning system.
How deep should these auxiliary drain pans be, AT
LEAST? - Answer-1-1/2 inches
,1|Page
The operation of the thermostatic expansion valve is
controlled by the temperature of the thermal expansion
valve and the pressure in the evaporator. Therefore, when
does the needle valve in the refrigeration system normally
open? - Answer-When the evaporator pressure is low and
the temperature is above normal
Heat exists down to absolute zero which is measured at a
temperature of? - Answer--460 degrees F
Appliance vent connectors and joints may be securely
joined with? - Answer-Sheet metal screws
At what degress fahrenheit below the desired evaporator
outside surface temperatures should the cut out pressure
of a pressure motor control be set? - Answer-10 degrees
Commercial air-cooled outdoor condenser units REQUIRE
approximately how many CFM of condenser air circulation
per horesepower? - Answer-1,000 CFM
Copper or brass pipe joints of iron pipe size shall be of
approved threaded, flanged, or brazed types. The tubing
,2|Page
joints and connections shall be approved flared, lapped,
swaged, or brazed joints, but shall NOT be of ________
type? - Answer-Compression
Mechanical room ventilation shall be designed to maintain
what condition within the room? - Answer-Negative
pressure
Where infrared heaters are installed, the minimum CFM of
ventilation air per 1,000 Btu/h input shall be? - Answer-4
Rafrigeration machinery rooms shall be provided with a
continuous source of outside air for ventilation and
removal of rejected heat. The exhaust system shall
continuously maintain the refrigeration machinery room at
______ water guage negative relative to adjacent spaces?
- Answer-0.05 inche
How much heat is required to melt a 10 pound block of ice
that is sitting at 32 degrees F into warm water given that
the heating temperature is at 80 degrees F? - Answer-
1,920 Btu/h
, 3|Page
In many condensing unit applications, it is necessary to
heat the compressor to evaporate liquid refrigerant
trapped in the oil. Many large compressors for commercial
applications are manufactured and equipped to handle this
situation using a _________? - Answer-Crankcase heater
Find the MINIMUM size chimney required: A fan assisted
Category 1 appliance with an input rating of 55,000 Btu/h
is to be vented with a single wall connector into a masonry
chimney that is 20 feet high with a 10 foot lateral. -
Answer-It is not recommended that this appliance be
connected tot his chimney
Given that a motor compressor has a 2" bore and a 3"
stroke, what would be the calculated piston displacement
in cubic inches? - Answer-9.42
A grain is a unit of weight equal to ___________, used to
indicate the amount of moisture in the air. - Answer-1/7000
lb
Vertical refrigerant lines in commerical refrigeration should
be sized to maintain a velocity of? - Answer-1,000 to 1,500
ft/min
Servicer_Installer - 588-MO-SL Contractor Exam
ACTUAL VERIFIED QUESTIONS AND ANSWERS
LATEST UPDATE.pdf
When computing heat leakage for a building, the U-value
for most types of construction can be obtained from
reference books. The unit of measure for U-value is
expressed in __________? - Answer-Btu/sq-ft/deg.F/Hr
Absolute zero temperature is the temperature at which all
molecular motion ceases at approximately
_______degrees Fahrenheit. - Answer--460 degrees F
What would be the calculated resistance of a circuits load,
given that the load draws a total current of 20 amperes,
and the circuit source operating voltage is 240 VAC? -
Answer-12.0
A contractor is working with auxiliary drain pans in a
secondary drain system for an air conditioning system.
How deep should these auxiliary drain pans be, AT
LEAST? - Answer-1-1/2 inches
,1|Page
The operation of the thermostatic expansion valve is
controlled by the temperature of the thermal expansion
valve and the pressure in the evaporator. Therefore, when
does the needle valve in the refrigeration system normally
open? - Answer-When the evaporator pressure is low and
the temperature is above normal
Heat exists down to absolute zero which is measured at a
temperature of? - Answer--460 degrees F
Appliance vent connectors and joints may be securely
joined with? - Answer-Sheet metal screws
At what degress fahrenheit below the desired evaporator
outside surface temperatures should the cut out pressure
of a pressure motor control be set? - Answer-10 degrees
Commercial air-cooled outdoor condenser units REQUIRE
approximately how many CFM of condenser air circulation
per horesepower? - Answer-1,000 CFM
Copper or brass pipe joints of iron pipe size shall be of
approved threaded, flanged, or brazed types. The tubing
,2|Page
joints and connections shall be approved flared, lapped,
swaged, or brazed joints, but shall NOT be of ________
type? - Answer-Compression
Mechanical room ventilation shall be designed to maintain
what condition within the room? - Answer-Negative
pressure
Where infrared heaters are installed, the minimum CFM of
ventilation air per 1,000 Btu/h input shall be? - Answer-4
Rafrigeration machinery rooms shall be provided with a
continuous source of outside air for ventilation and
removal of rejected heat. The exhaust system shall
continuously maintain the refrigeration machinery room at
______ water guage negative relative to adjacent spaces?
- Answer-0.05 inche
How much heat is required to melt a 10 pound block of ice
that is sitting at 32 degrees F into warm water given that
the heating temperature is at 80 degrees F? - Answer-
1,920 Btu/h
, 3|Page
In many condensing unit applications, it is necessary to
heat the compressor to evaporate liquid refrigerant
trapped in the oil. Many large compressors for commercial
applications are manufactured and equipped to handle this
situation using a _________? - Answer-Crankcase heater
Find the MINIMUM size chimney required: A fan assisted
Category 1 appliance with an input rating of 55,000 Btu/h
is to be vented with a single wall connector into a masonry
chimney that is 20 feet high with a 10 foot lateral. -
Answer-It is not recommended that this appliance be
connected tot his chimney
Given that a motor compressor has a 2" bore and a 3"
stroke, what would be the calculated piston displacement
in cubic inches? - Answer-9.42
A grain is a unit of weight equal to ___________, used to
indicate the amount of moisture in the air. - Answer-1/7000
lb
Vertical refrigerant lines in commerical refrigeration should
be sized to maintain a velocity of? - Answer-1,000 to 1,500
ft/min
