One major difference between a gas-fired furnace and a packaged unit with gas heat is that packaged units _____.

If a gas furnace continually trips on the temperature limit, a likely cause is a _____.

A packaged electric-electric unit _____.

One of the purposes of using a two-speed blower is to provide _____.

Which of the following is not part of the operating sequence of a natural-draft furnace?

If you can hear a spark from a spark ignitor, but the gas does not ignite, a likely cause is _____.

Each of these is a device for igniting the gas at the gas burners, except the _____.

A pilotless system is one in which _____.

The minimum reading you should expect when testing a loaded thermocouple is ___________.

What method is used to prove the burner flame in a furnace with a hot surface ignitor?

A service call is made to a customer who complains that when his furnace ignites, the flame rolls out in front of the heat exchanger. Tech A says that it’s due to a poor draft, possibly a blocked flue or heat exchanger. Tech B says that it has to do with the limit control or the fan switch control circuit. Which tech is correct?

A customer complains of headaches, sleepiness, and nausea. Tech A finds a crack in the heat exchanger and says that the furnace should be shut down. Tech B says the crack isn’t too serious, and that the furnace can operate temporarily but it must be cleaned. Which tech is correct?

A tech is servicing a standing pilot gas fired furnace. The complaint is that the burners are not lighting. Where should the tech start troubleshooting the system?

On a spark ignition system, the spark for ignition continues with no ignition of gas at the burners. Tech A concludes that the thermostat is defective. Tech B concludes that it is possibly the control module. Which tech is correct?

Which of the following is the correct test for a faulty cable on a direct spark ignition system?

A customer complains that the burners light on her system, but then immediately shut down. The problem is most likely to be

Which of the following would not be a proper procedure to perform on a direct spark ignition system where the spark continues, the burners light and the flames are immediately extinguished?

A hot surface ignition system does not ignite the main burner. After measuring voltage to the igniter, the tech should

The burners of a gas furnace that is equipped with an 115v hot surface igniter light for approximately 7seconds and then go out. What is problem that could cause this symptom?

The burners on a furnace having a hot surface ignition system light up, but quickly shut off. Tech A says that after testing the gas valve, he has determined that it is shorted. Tech B visually checked the flame sensor, cleaned it, and performed a continuity test. He faults a dirty sensor. Which tech is most likely to be correct?