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Defrost Heater
The defrost heater is a single-tube, glass-enclosed
radiant heater. It is held in place by 2 tabs on the
evaporator (1 on each side) and by a ceramic and
wire support.
To remove the defrost heater:
Access the freezer evaporator. (See
1.
Evaporator
.)
Note
:
During defrost, the heat conducting clip assists
•
in preventing the drain from icing closed. During
assembly, the clip must be installed on the
evaporator and inserted in the drain to prevent
drain freeze-up.
A ceramic and wire support prevents the heater
•
from sagging and touching the metal drain
trough if the glass is broken.
2. Remove the ceramic and wire support and the
heat conducting clip from the evaporator.
Bend the aluminum tabs back (located at each
3.
end of the defrost heater) and lower the heater
out of the evaporator.
Disconnect 2 lead wires and remove the heater.
4.
Heat Conducting
Clip
Ceramic and Wire
Support
Return Duct Heaters
A return duct heater has been added to each of
the 2 fresh food compartment return air ducts. The
heaters prevent water from freezing and blocking
the air
fl
ow in the ducts. Restricted ducts can cause
warm fresh food temperatures. (See
Airfl ow
.)
Return Duct
Outlets
Icemaker Fill Tube Heater
The
fi
ll tube heater is energized during the
defrost cycle when the defrost thermostat is
closed. Remove the evaporator cover to access
the icemaker
fi
ll tube heater. (See
Evaporator
.)
Disconnect the
fi
ll tube heater wire harness. The
resistance of the
fi
ll tube heater is approximately
2644
Ω
.
The heaters operate with 120 VAC and each heater
has an approximate resistance value of 440
Ω
.
The heaters are in a parallel circuit consisting of
2 duct heaters, icemaker
fi
ll tube heater, and the
defrost heater. The line voltage wires of the duct
heaters and the
fi
ll tube heater are connected to
the blue wire of the defrost heater. The neutral wires
of the heaters go through the over temperature
thermostat. The 2 duct heaters and the
fi
ll tube
heater are energized (along with the defrost heater)
during the defrost cycle when the over temperature
thermostat is closed.
Return Duct Heaters Test
If open duct heaters are suspected, perform the
following:
With the over temperature thermostat closed,
1.
test for approximately 27
Ω
(the equivalent
resistance of this parallel circuit) between J9
and J7-9 .
For a resistance reading other than
2.
approximately 27
Ω
, remove the evaporator
cover (See
Evaporator
.), disconnect the
fi
ll tube
heater, and one lead from the defrost heater.
Insert a volt ohm meter into the
fi
ll tube heater
receptacle. A reading of approximately 220
ohms at 70°F indicates both heaters are good.
Note:
The return duct heaters are integral to the
foamed in place internal ductwork of the refrigerator
and are not replaceable.
