22
M
AINTENANCE AND
S
ERVICING
Warning
Disconnect the furnace from the
power supply before servicing.
about 1-1/2" into the chamber. Make sure
porcelain insulator is in place for the ther-
mocouple to pass through on the steel
back plate. Replace clamp and screw.
(Excessive scaling, pitting, or cracks are
some indications that the thermocouple
may need to be replaced.)
20. Replace bottom cover of control unit.
21. Replace thermocouple cover.
22. If replacement of back insulation is neces-
sary, carefully redrill hole for thermocou-
ple, using back cover as guide.
23. Reconnect furnace to power supply.
24. Test operation of furnace.
To Replace Thermocouple
1.
Set furnace on its top.
2.
Remove thermocouple cover. (If equipped.)
3.
Remove screw and clamp holding the ther-
mocouple, then grasp the thermocouple at
the bend where it enters the chamber and
pull it straight back from the furnace. Retain
porcelain insulator.
4.
Remove bottom cover.
5.
Disconnect the thermocouple from the ter-
minal block by removing the screws on the
terminals. Pull the thermocouple through
the hole in the furnace base and discard.
6.
Insert the new thermocouple into the back
of the furnace chamber. Make sure the
porcelain insulator extends through the
steel back plate to prevent the lead wires
from touching metal.
Note
If the thermocouple touches metal,
this could short out the signal,
causing the control to display room
temperature. This could cause the
furnace temperature to run away,
possibly damaging furnace compo-
nents.
Summary of Contents for FB1310M
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