Nordyne E2EB 010H, Service Manual

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7 E2 Service Manual
Figure 4. Heating Element
then the transformer is nonfunctional and should
be replaced. Observe the transformer there should
be no distortion in shape, oil residue or odor. If any
of these symptoms exist replace the transformer.
Heating Elements (Figures 4 & 5)
The heating elements used are of modular design
consisting of helical-coiled nichrome resistance wire.
An insulated wire formed assembly supports the heating
elements. All elements are rated at 240 volts. Each
element is individually controlled by a switch of the
sequencing system and is protected by a limit switch.
The function of the heating element, of course, is to
heat the air passed across them by the blower system.
Testing Heating Elements (Ohmmeter)
1. Shut off all electric supply to furnace
2. Remove all wires from terminals of heating coils
3. Using the ohmmeter test from terminal to terminal
of the coil-must show continuity-if not replace
element assembly.
4. Using the ohmmeter test from heating element
terminal to ground wire in the control panel, there
should be no continuity. If there is the coil is
grounded and must be replaced.
Caution: Heating elements must always be replaced
by an identical kW replacement. Substitution by higher
kW’s or elements of a different design may result in
unsafe operation of the furnace. Lower kW rated
elements will reduce output and may result in
unsatisfactory operation of the appliance. Refer to
element rating labels and furnace wiring diagrams.
Refer to unit wiring diagram section for wiring of
sequencer for each model furnace.
Control Transformer (Figure 3)
All E2 furnaces are equipped with a 30 VA, 240/208
vac primary, 24 vac secondary transformer.
The function of the transformer is to supply the 24
volts for the low voltage circuit which activates the
controls. Note: never replace a transformer with one
of less VA rating: however a higher rated transformer
can replace a lower rated unit. Example: unit has 30
VA replacement can be 40 VA.
Checking Transformer
1. Using a voltmeter, test power supply on the primary
leads of the transformer- must be 240 v +/- 10%.
If less than 226 vac switch black and blue primary
leads.
2. Remove wires from the secondary side of the
transformer. Or find the area where the wires
terminate and remove from component.
3. Use the voltmeter check the output of the
transformer, it should read 22 to 28 volts. If not,
Figure 3. Transformer
Figure 5. Heating Elements in Furnace