OVEN-HEATING ELEMENTS.The ovens of
electric ranges are equipped with open or enclosed
elements. These include the rod and coil, suspended
coil, spiral-wound, or tubular types. Ovens have two
heating elements. One is located in the upper part of the
oven and the other in the lower part. Oven elements
work off a thermostat to control heat temperature and a
timing device for automatic shutoff, as shown in figure
start by checking to ensure that proper voltage is going
to the unit; then check each element and control device.
The heating element, though ruggedly constructed,
might become open-circuited. That can be checked
with an ohmmeter. Normal resistance is somewhat less
than 100 ohms. If elements are opened, replacement is
If the heating element checks normal but the unit
does not heat up, the controls should be checked.
Voltage measurement is the most reliable test for a
switch. When turned off, the measurement across the
switch terminals should read FULL-LINE
VOLTAGE, 120 or 240 volts. When the switch is ON,
the reading should be zero across the terminals. Any
voltage reading across the terminal of a closed switch
indicates a fault. Replacing a faulty switch involves the
disconnection and replacement of many wires. A sketch
or identifying tags should be used to ensure the correct
relocation of the wires.
Oven thermostats control temperature and are
factory-calibrated for that unit. Some units can be
recalibrated but most must be replaced. When
replacement is necessary, the exact type is preferred;
however, universal type replacement is available. The
Figure 7-6.Oven-heating circuit with two heating units.
manufacturers instructions that come with a thermostat
will give you the exact method for installing and
calibrating the device.
Faulty wiring is the final check. Unless arcing
damage is evident, test a wire by disconnecting both
ends from the circuit; then check it with an ohmmeter. A
good wire checks 0 ohms; a faulty one, infinity
Table 7-2 is a guide that should help you when
troubleshooting electric ranges; it lists the trouble,
probable cause, and remedy.
A hot-water heater is nothing more than a metal
water-storage tank with one or two electric heating
elements, thermostatically controlled to heat water in
the tank. Some of the electrical problems you may
encounter are as follows:
no power, defective
thermostat, thermostat out of calibration, or a defective
heater element or elements.
The hookup for a hot-water heater will vary
depending on the size and application of each unit.
Always refer to the manufacturers manual for wiring
instructions and the NEC© for any special
requirements. Most hot-water heaters that you will be
installing will have a wiring diagram similar to the one
shown in figure 7-7. The thermostat is in series with the
Figure 7-7.Wiring connections for an electric water beater,
having two heating units