ESCO GAS FURNACE QUESTIONS
AND CORRECT ANSWERS
A customer complains that a 2-year-old, direct, hot surface ignition furnace will not light. The
inducer motor runs, the pressure switch closes, and the igniter begins to glow, but there is no
ignition. The furnace locks out while attempting to light. After resetting the furnace, 17 VAC is
measured at the gas valve and the technician correctly concludes: ANSW✅✅The Electonic board
is faulty
The efficiency rating of gas-burning appliance is determined using: ANSW✅✅Annual Fuel
Utilization Efficiency (AFUE)
when the burners of a furnace are ignited the blower motor operation is delayed to:
ANSW✅✅Allow heat exchanger to warm up
Typical condensing furnaces have an AFUE rating of at least ANSW✅✅90%
Burning one cubic foot of natural gas will produce approximately _____ BTU's ANSW✅✅900-
1,100 BTU
The Natural Fuel Gas code classifies a vent system for a condensing furnace as :
ANSW✅✅Category IV
what type of draft is used to move flue gas through the heat exchanger and into the venting system
in modern gas-fired furnaces? ANSW✅✅Mechanical
A gas furnace has an integrated furnace control (IFC). How is the fan cycled during heating?
ANSW✅✅Heat Relay
What reading should a good thermocouple produce on a DC meter ANSW✅✅30 millivolts
A furnace nameplate specifies a temperature rise of 40 to 70 degrees. Temperature measurements
indicate a rise of 80 degrees. The most appropriate action is to: ANSW✅✅Increase the fan speed
The most common burner used in induced draft furnace is: ANSW✅✅In-shot
, You are installing 1/2 and 3/4 black iron pipe to a natural gas furnace. When threading, what is the
approximate number of threads to cut? ANSW✅✅7-10
When exposed to low concentrations of carbon monoxide, healthy adults may exhibit:
ANSW✅✅Headaches and Nausea
If voltage is applied across two speed terminals on a fan motor, the motor will ANSW✅✅Short-
out/Burn-out
to react to a change in temperature, the fan/limit switch in a standing pilot furnace uses a helical
shaft made of ANSW✅✅Bi-metal
How much combustion air is required to burn and properly vent once cubic foot of natural gas?
ANSW✅✅10 Cu.Ft
most thermostats contain one or more sets of contacts to control the heating system of a
conditioned space. These contacts ANSW✅✅Are thermally Actuated.
Carbon monoxide (C0) is dangerous. What is the maximum level of undiluted CO that is acceptable in
a sample of the flue gas? ANSW✅✅400 ppm
Burning on cubic foot of liquid petroleum (LP) gas completely will produce approximately?
ANSW✅✅2,000-2,500 BTU
Pressure drop in a natural gas piping system primarily occurs due to: ANSW✅✅Friction or
Resistance caused by the pipe and fittings installed in the piping system.
liquefied petroleum (LP) gas has a specific gravity of: ANSW✅✅1.5 to 2.0
The reason for a cross-lighter or carry over on a gas burner is to: ANSW✅✅Provide smooth
lighting of all burners.
AND CORRECT ANSWERS
A customer complains that a 2-year-old, direct, hot surface ignition furnace will not light. The
inducer motor runs, the pressure switch closes, and the igniter begins to glow, but there is no
ignition. The furnace locks out while attempting to light. After resetting the furnace, 17 VAC is
measured at the gas valve and the technician correctly concludes: ANSW✅✅The Electonic board
is faulty
The efficiency rating of gas-burning appliance is determined using: ANSW✅✅Annual Fuel
Utilization Efficiency (AFUE)
when the burners of a furnace are ignited the blower motor operation is delayed to:
ANSW✅✅Allow heat exchanger to warm up
Typical condensing furnaces have an AFUE rating of at least ANSW✅✅90%
Burning one cubic foot of natural gas will produce approximately _____ BTU's ANSW✅✅900-
1,100 BTU
The Natural Fuel Gas code classifies a vent system for a condensing furnace as :
ANSW✅✅Category IV
what type of draft is used to move flue gas through the heat exchanger and into the venting system
in modern gas-fired furnaces? ANSW✅✅Mechanical
A gas furnace has an integrated furnace control (IFC). How is the fan cycled during heating?
ANSW✅✅Heat Relay
What reading should a good thermocouple produce on a DC meter ANSW✅✅30 millivolts
A furnace nameplate specifies a temperature rise of 40 to 70 degrees. Temperature measurements
indicate a rise of 80 degrees. The most appropriate action is to: ANSW✅✅Increase the fan speed
The most common burner used in induced draft furnace is: ANSW✅✅In-shot
, You are installing 1/2 and 3/4 black iron pipe to a natural gas furnace. When threading, what is the
approximate number of threads to cut? ANSW✅✅7-10
When exposed to low concentrations of carbon monoxide, healthy adults may exhibit:
ANSW✅✅Headaches and Nausea
If voltage is applied across two speed terminals on a fan motor, the motor will ANSW✅✅Short-
out/Burn-out
to react to a change in temperature, the fan/limit switch in a standing pilot furnace uses a helical
shaft made of ANSW✅✅Bi-metal
How much combustion air is required to burn and properly vent once cubic foot of natural gas?
ANSW✅✅10 Cu.Ft
most thermostats contain one or more sets of contacts to control the heating system of a
conditioned space. These contacts ANSW✅✅Are thermally Actuated.
Carbon monoxide (C0) is dangerous. What is the maximum level of undiluted CO that is acceptable in
a sample of the flue gas? ANSW✅✅400 ppm
Burning on cubic foot of liquid petroleum (LP) gas completely will produce approximately?
ANSW✅✅2,000-2,500 BTU
Pressure drop in a natural gas piping system primarily occurs due to: ANSW✅✅Friction or
Resistance caused by the pipe and fittings installed in the piping system.
liquefied petroleum (LP) gas has a specific gravity of: ANSW✅✅1.5 to 2.0
The reason for a cross-lighter or carry over on a gas burner is to: ANSW✅✅Provide smooth
lighting of all burners.
