Exam
Before working on an electric furnace the tech should - ans-Review diagram, remove jewelry, and
follow safety procedures. ALL OF THE ABOVE.
A GFCI circuit breaker - ans-detects current leaks to groound
the conductor in an electric heat element is usually made of - ans-Nichrome
An example of resistive load is - ans-crankcase heater
an example of an inductive load is - ans-motor
an electric furnace is marked 208/230 single phase 60Hz A tech reads 200 vac at the power supply and
determines - ans-the voltage is too low
voltage imbalance between any leg of 3 phase power supply may not exceed - ans-2%
the limit switch on an electric furnace is a - ans-Automatic reset switch
the sequencer timers on electric heater will usually energize the 1st heating element after a time delay
of - ans-1 to 30 sec
, the amount of btus produced by 1 watt of electricity is - ans-3.413 btus
a tech reads 60 amps with a clamp on amp meter on a forced air furnace. the supply voltage is 230 volts
AC, approx how many watts is the furnace using - ans-13,800
a furnace is using 15,500 watts approx Kw - ans-15.5 Kw
a sequencer timer use _____ to close the contact points to the heater element - ans-heated snap-discs
or bi-metal strips
an electric furnace heating thermostat must - ans-open on rise close on drop
a standard thermostat heat anticipator is ____ and wired in ____ with the heating control - ans-
adjustable/series
some thermostat manufacturers require a jumper connection on the thermostat subbase of heating and
cooling thermostat in order to - ans-use a single transformer
most electric heat elements use the following safties to prevent overheating - ans-snap disc and
fusible link
a tech reads 70 amps to the single phase heater . the supply voltage is 230 volts Ac. Approx how many
btus is the furnace producing - ans-54,949
the control that prevents duct heater from operating unless there is adequate supply air is - ans-fan
interlock
the COP for electric resistance heat is - ans-1 to 1