HVAC (100 Question) Exam with All Correct & 100%
Verified Answers |Latest Version| Already Graded A+
A gas furnace installed in a garage, the burners need to be ______" above the ground ✔Correct
Answer-18in above the floor
A description of how a bi-metal switch operates the blower motor? ✔Correct Answer-temperature
on-Time off
Redundant gas valves used on a gas furnace will shut down if gas pressure exceeds ______?
✔Correct Answer-13.5 in W.C (1/2psi)
Burning one cubic foot of LP gas completely will produce approximately _______BTUs? ✔Correct
Answer-2000-2500
LP gas has a specified gravity of_______? ✔Correct Answer-1.5-2.0
What is the purpose of a spoiler screw located on a burner or adjustable shutter? ✔Correct
Answer-mix gas and primary air
Furnace limit switches are wired in series with the _____ ______? ✔Correct Answer-gas valve
The top of a ladder should be ____ above the support point? ✔Correct Answer-1-3ft
A technician determines a furnace has a bad heat exchanger. They should? ✔Correct Answer-
inform the homeowner and turn the gas off
A natural gas furnace should have _____"WC at the manifold ✔Correct Answer-3.5
The vent system for a condensing furnace is category ______? ✔Correct Answer-IV
Type B vent must be kept ____" away from combustible material? ✔Correct Answer-1
Typical condensing furnaces have a rating of _____% ✔Correct Answer-at least 90%
You have installed a condensing furnace vent(category IV) on a roof the elbow of the combustion air
should point _______? ✔Correct Answer-down
The reason thermostats have anticipators is to ___________________________? ✔Correct
Answer-reduce overshoot
The proper name for natural gas is? ✔Correct Answer-fossil gas
Burning one cubic foot of natural gas will produce approximately _______BTUs? ✔Correct Answer-
1015
A furnace nameplate says temp rise is 40-70 but you have 80 what should you do? ✔Correct
Answer-increase fan speed
, A BTU is the amount of heat required to raise the temp of one pound of water ____________?
✔Correct Answer-one degree Fahrenheit
Natural gas piping must be sized to prevent excessive pressure drop. The allowable drop by code is
___? ✔Correct Answer-.55 in WC
Gas piping must be installed with a pitch of ✔Correct Answer-1/4 inch per 15 foot run
Pipe dope should be applied to. ✔Correct Answer-male threads less two end threads
A tech is installing a copper elbow on a copper LP gas line should use? ✔Correct Answer-15% silver
solder
The ignition temperature of natural gas is? ✔Correct Answer-1100 F - 1200 F
Air that is mixed with gas in the burner is called? ✔Correct Answer-Primary air
What is the volume of flue gas produced from a natural gas furnace with a draft diverter?
✔Correct Answer-30 cu ft
The purpose of a flue baffle is to ✔Correct Answer-Increase heat exchange
The LP gas pressure supplied to the gas valve should be? ✔Correct Answer-11-13 in WC
An installed furnace should have a minimum service access of _____"? ✔Correct Answer-24
Which conditions below would cause the temperature limit safety switch to shut off the burners>
✔Correct Answer-fan motor failure
The cut off plate is part of the _______? ✔Correct Answer-blower housing
A spud or burner orifice does ? ✔Correct Answer-meters gas to the burners
A good thermocouple should read _____ on a DC meter ✔Correct Answer-30 Millivolts (MV)
Fan time/temperature delay switches are used on a gas furnace to ______? ✔Correct Answer-
allow the heat exchange to warm up
What tool would a tech use to measure airflow? ✔Correct Answer-Anemometer
A furnace with a hot surface ignitor will not light Before changing the ignitor you should? ✔Correct
Answer-check voltage to ignitor
A tech starts a standing pilot furnace and notices on main ignition the flames roll out the tech
suspects? ✔Correct Answer-a faulty vent
A tech servicing a LP furnace finds large amounts of soot in the heat exchanger What could cause
this? ✔Correct Answer-orifice to large
A tech lights a furnace and tries to adjust the gas but the flames don't change what could the cause?
✔Correct Answer-a defective gas valve regulator
Verified Answers |Latest Version| Already Graded A+
A gas furnace installed in a garage, the burners need to be ______" above the ground ✔Correct
Answer-18in above the floor
A description of how a bi-metal switch operates the blower motor? ✔Correct Answer-temperature
on-Time off
Redundant gas valves used on a gas furnace will shut down if gas pressure exceeds ______?
✔Correct Answer-13.5 in W.C (1/2psi)
Burning one cubic foot of LP gas completely will produce approximately _______BTUs? ✔Correct
Answer-2000-2500
LP gas has a specified gravity of_______? ✔Correct Answer-1.5-2.0
What is the purpose of a spoiler screw located on a burner or adjustable shutter? ✔Correct
Answer-mix gas and primary air
Furnace limit switches are wired in series with the _____ ______? ✔Correct Answer-gas valve
The top of a ladder should be ____ above the support point? ✔Correct Answer-1-3ft
A technician determines a furnace has a bad heat exchanger. They should? ✔Correct Answer-
inform the homeowner and turn the gas off
A natural gas furnace should have _____"WC at the manifold ✔Correct Answer-3.5
The vent system for a condensing furnace is category ______? ✔Correct Answer-IV
Type B vent must be kept ____" away from combustible material? ✔Correct Answer-1
Typical condensing furnaces have a rating of _____% ✔Correct Answer-at least 90%
You have installed a condensing furnace vent(category IV) on a roof the elbow of the combustion air
should point _______? ✔Correct Answer-down
The reason thermostats have anticipators is to ___________________________? ✔Correct
Answer-reduce overshoot
The proper name for natural gas is? ✔Correct Answer-fossil gas
Burning one cubic foot of natural gas will produce approximately _______BTUs? ✔Correct Answer-
1015
A furnace nameplate says temp rise is 40-70 but you have 80 what should you do? ✔Correct
Answer-increase fan speed
, A BTU is the amount of heat required to raise the temp of one pound of water ____________?
✔Correct Answer-one degree Fahrenheit
Natural gas piping must be sized to prevent excessive pressure drop. The allowable drop by code is
___? ✔Correct Answer-.55 in WC
Gas piping must be installed with a pitch of ✔Correct Answer-1/4 inch per 15 foot run
Pipe dope should be applied to. ✔Correct Answer-male threads less two end threads
A tech is installing a copper elbow on a copper LP gas line should use? ✔Correct Answer-15% silver
solder
The ignition temperature of natural gas is? ✔Correct Answer-1100 F - 1200 F
Air that is mixed with gas in the burner is called? ✔Correct Answer-Primary air
What is the volume of flue gas produced from a natural gas furnace with a draft diverter?
✔Correct Answer-30 cu ft
The purpose of a flue baffle is to ✔Correct Answer-Increase heat exchange
The LP gas pressure supplied to the gas valve should be? ✔Correct Answer-11-13 in WC
An installed furnace should have a minimum service access of _____"? ✔Correct Answer-24
Which conditions below would cause the temperature limit safety switch to shut off the burners>
✔Correct Answer-fan motor failure
The cut off plate is part of the _______? ✔Correct Answer-blower housing
A spud or burner orifice does ? ✔Correct Answer-meters gas to the burners
A good thermocouple should read _____ on a DC meter ✔Correct Answer-30 Millivolts (MV)
Fan time/temperature delay switches are used on a gas furnace to ______? ✔Correct Answer-
allow the heat exchange to warm up
What tool would a tech use to measure airflow? ✔Correct Answer-Anemometer
A furnace with a hot surface ignitor will not light Before changing the ignitor you should? ✔Correct
Answer-check voltage to ignitor
A tech starts a standing pilot furnace and notices on main ignition the flames roll out the tech
suspects? ✔Correct Answer-a faulty vent
A tech servicing a LP furnace finds large amounts of soot in the heat exchanger What could cause
this? ✔Correct Answer-orifice to large
A tech lights a furnace and tries to adjust the gas but the flames don't change what could the cause?
✔Correct Answer-a defective gas valve regulator
