28
Muffle (Heating Element) Replacement
a.
Disconnect from power supply.
b.
Set furnace on its door.
c.
Remove (one piece) top, back and bottom cover.
d.
Disconnect element lead wires from relays. (Note
placement and connection of.)
e.
Remove clip from thermocouple and pull thermocouple
out of muffle.
f.
Remove metal retaining band from defective muffle.
g.
Loosen top adjustment bracket and remove defective
muffle.
h.
Insert new muffle with vent hole facing the top of unit.
i.
Readjust top bracket to fit snugly up against muffle.
Make sure muffle is laying flush against front case sec-
tion.
j.
Reinstall metal retaining band and tighten until muffle
seats firmly into case section.
k.
Reconnect element lead wires.
On the 120V or 100V muffle there are three element
lead wires. Connect the front and the back element
lead wires to the mechanical relay. Connect the middle
element lead wire to the solid state relay.
On the 230V and 240V muffles there are two element
lead wires. Connect the front element lead wire to me-
chanical relay. Connect the back element lead wire to
the solid state relay.
l.
Reinstall the thermocouple and the retaining clip.
m.
Reinstall the cover section.
n.
Set the furnace upright and test the operation of the
furnace.
M
AINTENANCE
AND
S
ERVICIMG
NOTE
Make sure yellow thermocouple lead wire is con-
nected to terminal #9 on back of the controller.
Make sure red thermocouple lead wire is con-
nected to terminal #10 on back of the controller.
Make sure the exposed section of the T/C lead
wires are not contacting each other.
NOTE
Make sure the black insulation sleeving covers
the exposed portion of the element lead wires.
NOTE
Make sure the exposed section of the T/C lead
wires are not contacting each other.
NOTE
Perform only maintenance described in this
manual. Contact an authorized dealer or our fac-
tory for parts and assistance.
