pg. 1 NATE -GAS & HEAT EXAM NEWEST 2025 ACTUAL EXAM|
COMPLETE QUESTIONS AND VERIFIED ANSWERS (100%
CORRECT ANSWERS) ALREADY GRADED A+
The measurements required to calculate the CFM of a gas furnace are: -
ANSWER - Entering air temperature Leaving air temperature Outdoor ambient and rated capacity
The reason for checking the temperature rise across the heat exchanger of
a gas furnace is to: - ANSWER - Compare temperature differential to
nameplate rating
The technician is servicing a gas furnace located in a basement and the complaint is "not enough heat". The following conditions exist: Properly sized furnace is operating correctly; Temperature rise is within specification; Filter is clean and CFM from blower is running. - ANSWER - The most likely problem with this system is the air side is leaking at one or more supply ducts
The technician is checking the operation of an induced draft furnace with
an atmospheric burner and a direct ignition system. On a call for heat the:
Vent blower comes on; Igniter glows; Main burner does not light; - ANSWER - The next check would be the gas supply and/or gas valve
The complaint is that there is static electricity throughout the house. The home has a bypass humidifier. The technician has checked the humidistat and verified that it is set properly. - ANSWER - The next check would be to see if the humidifier damper is open. 1 / 3
pg. 2 A customer complains the unit is "blowing cold air". The technician determines that the problem occurs at the end of the heating sequence.The furnace used an electronic integrated blower control. - ANSWER - The likely problem with the system is the blower off delay is set too long.
Undersized ductwork causes: - ANSWER - High sound levels; Insufficient
air quantities; High static pressure
For accuracy, the preferred locations for the temperature probes when
measuring temperature rise across a heat exchanger in a gas furnace is to:
- ANSWER - Read inlet temp in the return plenum as close as possible to
the heat exchanger. Read outlet temp in supply plenum as close as possible, but beyond "line of sight" to the heat exchanger.
A system airflow check determines that supply static is 0.15 in. W.C. And
return static are a -0.55 in. W.C. These readings tell the technician: -
ANSWER - The difference between supply static and return static is unacceptably low.
The following measurements would be needed to properly evaluate a
complaint of "drafty" operation with a gas heating system: - ANSWER -
System TD, Drop and static pressure
A furnace is inoperative because of a failure in the ignition sequence at the flame proving stage. To check the flame proving circuit the technician
would: - ANSWER - Connect a microammeter set to DC microamps in the
sensor circuit and operate the furnace.
What is the problem when a flame on a high efficiency gas furnace is burning primarily yellow? - ANSWER - The flame is burning without sufficient combustion air 2 / 3
pg. 3 A technician receives a call that a gas furnace is running constantly in heating and cannot be shut off. While checking the thermostat, the technician observes the burner shuts off by removing the wire on the R terminal on the thermostat subbase. - ANSWER - Most likely there is a short in the thermostat subbase
The continuity of a fuse should be tested by: - ANSWER - Checking
resistance with power off
A standing pilot furnace uses a relay for controlling the supply blower. On a call for heat, the burner lights, the fan control closes, but the blower does not run. A check of voltage at the blower relay coil shows 24V. The load
side measures 0V. The technician should replace what: - ANSWER - Fan
relay
The following is true about fan run capacitors. - ANSWER - The fan capacitor shifts the electrical phase angle
The pressure switch on an induced draft blower system is not closing
properly, the technician can check the pressure using a: - ANSWER -
Bourdon tube pressure gauge
The blower access door is removed from a powered-up gas furnace with a door interlock switch. Assume the switch has not been modified, the
technician read across the door interlock switch terminals should get: -
ANSWER - Volts
A damaged section of double wall vent pipe is to be replaced with a section
produced by a different manufacturer: - ANSWER - The installer should
check the new section for compatible locking joints
- / 3