Electric Heat ESCO - HVAC Excellence
Exam
Before working on an electric furnace the tech should - ✅✅
-Review diagram,
remove jewelry, and follow safety procedures. ALL OF THE ABOVE.
A GFCI circuit breaker - ✅✅-detects current leaks to groound
the conductor in an electric heat element is usually made of - ✅✅-Nichrome
An example of resistive load is - ✅✅-crankcase heater
an example of an inductive load is - ✅✅-motor
✅✅
an electric furnace is marked 208/230 single phase 60Hz A tech reads 200 vac at
the power supply and determines - -the voltage is too low
✅✅
voltage imbalance between any leg of 3 phase power supply may not exceed -
-2%
the limit switch on an electric furnace is a - ✅✅-Automatic reset switch
✅✅
the sequencer timers on electric heater will usually energize the 1st heating element
after a time delay of - -1 to 30 sec
the amount of btus produced by 1 watt of electricity is - ✅✅-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 - -13,800
a furnace is using 15,500 watts approx Kw - ✅✅-15.5 Kw
✅✅
a sequencer timer use _____ to close the contact points to the heater element -
-heated snap-discs or bi-metal strips
an electric furnace heating thermostat must - ✅✅-open on rise close on drop
✅✅
a standard thermostat heat anticipator is ____ and wired in ____ with the heating
control - -adjustable/series
, ✅✅
some thermostat manufacturers require a jumper connection on the thermostat
subbase of heating and cooling thermostat in order to - -use a single
transformer
✅✅
most electric heat elements use the following safties to prevent overheating -
-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 - -54,949
✅✅
the control that prevents duct heater from operating unless there is adequate supply
air is - -fan interlock
the COP for electric resistance heat is - ✅✅-1 to 1
✅✅
what is the maximum kW element used on each contact of a residential heat
sequencer - -5 kW
✅✅-240
electric heaters are generally rated at ____ volts ac for kW output -
the first stage of a sequencer usually has a set of contacts to - ✅✅-start the blower
fan motor
✅✅
an automatic reset safety on a heater element generally opens at ____*F -
-130-190*F
most heating elements are mounted on which type of insulator - ✅✅-mica or
ceramic
✅✅
a 10 kW electric heater operating at 240 v draws 42 amps, what will a 10 kW heater
wired to 480 volts draw - -21 amps
the purpose of a sequencer is to - ✅✅-avoid a sudden power load
✅✅
two major factors in determining the temp rise of an electric furnace are -
-furnace KW and CFM
a major cause of electrical heat element burn out - ✅✅-low airflow
✅✅
a tech is checking the resistance on delta wired 3 phase 240 v 15 kW electic duct
heater if one element is open he would read - -L1 to L2 22Ohm L1 to L3 22ohm
L2 to L3 infinity
the purpose of setting a heat anticipator properly is to - ✅✅-control cycling time
Exam
Before working on an electric furnace the tech should - ✅✅
-Review diagram,
remove jewelry, and follow safety procedures. ALL OF THE ABOVE.
A GFCI circuit breaker - ✅✅-detects current leaks to groound
the conductor in an electric heat element is usually made of - ✅✅-Nichrome
An example of resistive load is - ✅✅-crankcase heater
an example of an inductive load is - ✅✅-motor
✅✅
an electric furnace is marked 208/230 single phase 60Hz A tech reads 200 vac at
the power supply and determines - -the voltage is too low
✅✅
voltage imbalance between any leg of 3 phase power supply may not exceed -
-2%
the limit switch on an electric furnace is a - ✅✅-Automatic reset switch
✅✅
the sequencer timers on electric heater will usually energize the 1st heating element
after a time delay of - -1 to 30 sec
the amount of btus produced by 1 watt of electricity is - ✅✅-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 - -13,800
a furnace is using 15,500 watts approx Kw - ✅✅-15.5 Kw
✅✅
a sequencer timer use _____ to close the contact points to the heater element -
-heated snap-discs or bi-metal strips
an electric furnace heating thermostat must - ✅✅-open on rise close on drop
✅✅
a standard thermostat heat anticipator is ____ and wired in ____ with the heating
control - -adjustable/series
, ✅✅
some thermostat manufacturers require a jumper connection on the thermostat
subbase of heating and cooling thermostat in order to - -use a single
transformer
✅✅
most electric heat elements use the following safties to prevent overheating -
-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 - -54,949
✅✅
the control that prevents duct heater from operating unless there is adequate supply
air is - -fan interlock
the COP for electric resistance heat is - ✅✅-1 to 1
✅✅
what is the maximum kW element used on each contact of a residential heat
sequencer - -5 kW
✅✅-240
electric heaters are generally rated at ____ volts ac for kW output -
the first stage of a sequencer usually has a set of contacts to - ✅✅-start the blower
fan motor
✅✅
an automatic reset safety on a heater element generally opens at ____*F -
-130-190*F
most heating elements are mounted on which type of insulator - ✅✅-mica or
ceramic
✅✅
a 10 kW electric heater operating at 240 v draws 42 amps, what will a 10 kW heater
wired to 480 volts draw - -21 amps
the purpose of a sequencer is to - ✅✅-avoid a sudden power load
✅✅
two major factors in determining the temp rise of an electric furnace are -
-furnace KW and CFM
a major cause of electrical heat element burn out - ✅✅-low airflow
✅✅
a tech is checking the resistance on delta wired 3 phase 240 v 15 kW electic duct
heater if one element is open he would read - -L1 to L2 22Ohm L1 to L3 22ohm
L2 to L3 infinity
the purpose of setting a heat anticipator properly is to - ✅✅-control cycling time
