MD HVAC MASTERS EXAM WITH
CORRECT ACTUAL QUESTIONS AND
CORRECTLY WELL DEFINED ANSWERS
LATEST ALREADY GRADED A+ 2025 – 2026
An 18" high-heat metal chimney shall have a minimum
sheet steel thickness of ____________. - ANSWERS-12 gauge
A residential heating system has 16" galvanized duct. The
minimum thickness required by code is __________. -
ANSWERS-26 gauge
When installing an exhaust duct for down flow domestic
range hoods, a _____________ is required. - ANSWERS-
Backdraft Damper
,The purpose of a condenser is ________________. -
ANSWERS-Reject heat which is absorbed by the refrigerant
Prior to retrofitting refrigerant systems containing 250 lbs.
of refrigerant, what must be done? - ANSWERS-Notify code
officials
______________ is a tube or pipe used to carry refrigerant
gas from evaporator to the compressor - ANSWERS-Suction
line
Commercial appliance exhaust outlets that terminate above
roof shall have the discharge opening located not less than
___________ inches above the roof surface. - ANSWERS-40
A run winding in a compressor has _____________
resistance than the start winding. - ANSWERS-Less
A duct that has an operating temperature of 150 deg F shall
be insulated to limit the exposed surface temperature to
___________. - ANSWERS-120 °F
,Hydronic pipe system should be cleaned with water and
_____________ after installation. - ANSWERS-Trisodium
Phosphate
Using a psychrometric chart in the Modern Refrigeration,
what will the wet bulb be if the dry bulb is 80 degrees and
the humidity is 30%? - ANSWERS-60 °F
Outside air exhaust and intake openings shall be located a
minimum of ____________ feet from lot lines or building on
the same lot. - ANSWERS-10
Down - pipe support material must not promote: -
ANSWERS-Galvanic action
Central HVAC systems shall have air filters installed in which
of the following locations? - ANSWERS-Upstream from any
exchanger coil
An auxiliary drain pan used in secondary drain systems for
an a/c systems shall have a minimum depth of ________
inch. - ANSWERS-1 ½
, A ventilation supply system shall deliver the required rate of
supply air within an occupied space minimum of
____________ above the floor. - ANSWERS-3"
In a unit controlled by a thermostat the differential is the
difference between ____________. - ANSWERS-Temperature
at which the switch turns the burners on and the
temperature at which the switch turns the burners off
A ___________ is used to measure relative humidity by
comparing wet/dry bulb temperatures. - ANSWERS-Sling
Psychrometric
A (n) ___________ prevents slugging in a heat pump system.
- ANSWERS-Accumulator
Any appliance in which the products of combustion at the
point of entrance to the flue under normal operating
conditions have a temperature of 1000 degrees is a
____________ appliance. - ANSWERS-Low
A connector to a chimney flue shall be at least __________
the lowest portion of the interior of the flue. - ANSWERS-
12" above
CORRECT ACTUAL QUESTIONS AND
CORRECTLY WELL DEFINED ANSWERS
LATEST ALREADY GRADED A+ 2025 – 2026
An 18" high-heat metal chimney shall have a minimum
sheet steel thickness of ____________. - ANSWERS-12 gauge
A residential heating system has 16" galvanized duct. The
minimum thickness required by code is __________. -
ANSWERS-26 gauge
When installing an exhaust duct for down flow domestic
range hoods, a _____________ is required. - ANSWERS-
Backdraft Damper
,The purpose of a condenser is ________________. -
ANSWERS-Reject heat which is absorbed by the refrigerant
Prior to retrofitting refrigerant systems containing 250 lbs.
of refrigerant, what must be done? - ANSWERS-Notify code
officials
______________ is a tube or pipe used to carry refrigerant
gas from evaporator to the compressor - ANSWERS-Suction
line
Commercial appliance exhaust outlets that terminate above
roof shall have the discharge opening located not less than
___________ inches above the roof surface. - ANSWERS-40
A run winding in a compressor has _____________
resistance than the start winding. - ANSWERS-Less
A duct that has an operating temperature of 150 deg F shall
be insulated to limit the exposed surface temperature to
___________. - ANSWERS-120 °F
,Hydronic pipe system should be cleaned with water and
_____________ after installation. - ANSWERS-Trisodium
Phosphate
Using a psychrometric chart in the Modern Refrigeration,
what will the wet bulb be if the dry bulb is 80 degrees and
the humidity is 30%? - ANSWERS-60 °F
Outside air exhaust and intake openings shall be located a
minimum of ____________ feet from lot lines or building on
the same lot. - ANSWERS-10
Down - pipe support material must not promote: -
ANSWERS-Galvanic action
Central HVAC systems shall have air filters installed in which
of the following locations? - ANSWERS-Upstream from any
exchanger coil
An auxiliary drain pan used in secondary drain systems for
an a/c systems shall have a minimum depth of ________
inch. - ANSWERS-1 ½
, A ventilation supply system shall deliver the required rate of
supply air within an occupied space minimum of
____________ above the floor. - ANSWERS-3"
In a unit controlled by a thermostat the differential is the
difference between ____________. - ANSWERS-Temperature
at which the switch turns the burners on and the
temperature at which the switch turns the burners off
A ___________ is used to measure relative humidity by
comparing wet/dry bulb temperatures. - ANSWERS-Sling
Psychrometric
A (n) ___________ prevents slugging in a heat pump system.
- ANSWERS-Accumulator
Any appliance in which the products of combustion at the
point of entrance to the flue under normal operating
conditions have a temperature of 1000 degrees is a
____________ appliance. - ANSWERS-Low
A connector to a chimney flue shall be at least __________
the lowest portion of the interior of the flue. - ANSWERS-
12" above
