A furnace that uses a direct hot surface ignition system will not ignite the burners. Tech A measures 50 ohms on the hot surface igniter and says that it is defective. Tech B also measures 50 ohms on the igniter and says that the igniter is not defective; the problem is probably a bad control module. Which tech is correct?

A tech observes a furnace with an intermittent pilot retrofit ignition system and finds that although a pilot light exists, the main burners will not ignite: he concludes that

When a measurement is taken to record temperature rise, the supply air temperature should be taken

One of the reasons that a pressure switch fails to close is;

When there is not sufficient air available for the combustion process, one element of incomplete combustion that can become fatal is

A tech observes a gas furnace in operation in which the inducer motor is operating but no ignition is occurring. The component most likely at fault is the

To check a gas furnace with flame rectification, the tech would check;

The type of voltage that a thermocouple produces is

When installing thermostat wire to a gas furnace using a millivolt thermopile generator, care should be taken to prevent extreme lengths of wire because

To help reduce noise transmitting from a furnace installed in an attic the installer could

The reason for the International or National Fuel Gas Code is to

When installing a electromechanical heating and cooling thermostat which of the following is true?

When installing a programmable thermostat that is used on a heating and cooling system that uses only one control circuit transformer,

Which of the following will cause excessive temperature rise on a forced air furnace?