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UNIT 63 REVIEW QUESTIONS ANSWER KEY GO BACK TO INDEX
63-1) List three ways of checking the heating elements of an electric furnace.
63-2) Describe how a clamp on ammeter can be used to check an electric furnace.
63-3) What would be the resistance reading of an open heating element?
63-4) A technician reads 240 volts across the thermal limit to the first strip heater on
an electric furnace. What does this mean?
63-5) List three ways of checking an overload in an electric furnace.
Voltage drop, current drop, tattle tale
63-6) What should always be checked when replacing a limit?
63-7) What should always be checked when replacing a transformer?
63-8) What is the airflow through a furnace with the following readings: Voltage at
the strips of 235 volts; Current draw of 39.5 amps; Return air temperature 72°F;
63-9) What type of oil should be used when lubricating the motor bearings?
63-10) Explain how a stuck heating sequencer can keep the fan operating
63-11) What is the correct remedy for a wire with one end that has overheated?
63-12) Why should relay slide-on posts not be sanded to clean off oxidation?
63-13) How can over lubricating a blower motor be detrimental?
63-14) What are the two general types of sequencers used on electric furnaces?
63-15) Describe two ways that electric furnaces control the blower motor.
63-16) What is the purpose of the white ceramic pieces on the strip heaters?
63-17) Why is a visual check of the heating strips on an electric furnace difficult to
accomplish?
63-18) Why are terminal and wire resistance values critical in electric furnaces?
63-19) What are two types of safety most electric furnaces utilize?
63-20) Why are the strips on an electric furnace staged to turn on in sequence instead
of being energized all at one time?
