e. Refrigerator Maintenance.
b. Cleaning. Clean the steel tray and the chamber
interior, using a clean cloth and mild soap and water
Door seal adjustment.
(a) Each hinge is provided with slotted mounting
c. Removal and Replacement Procedures.
holes in the wing that is fastened to the door.
Procedures for removing and replacing the muffle unit,
(b) If it becomes necessary to remove the complete
thermocouple, on-off switch and pilot light are as follows:
door assembly, remove the screws that secure the hinge
Removal of burned-out muffle and
to the cabinet exterior; the door gasket pressure will not
(a) Remove three screws (7, fig. 3-1) from sides of
the case and remove the backplate (6).
(a) The thermostat is mounted on the right side of
(b) Remove loose insulation blocks.
top interior, and is secured by two screws.
(c) Lay the furnace on its face. Remove the
(b) To adjust the thermostat for a warmer or colder
thermocouple (5) from the instrument, marking each
setting, an indicator knob is provided. Turn the knob
wire. Withdraw the thermocouple from the hole. Remove
clockwise for a warmer temperature.
the metal air vent from the hole.
(c) Changing the thermostat indicator setting to a
(d) Remove the nuts and the wires from the muffle
warmer or colder position changes the cutout
temperature only. The thermostat indicator should not be
changed more than once each 24 hours, and then by
(e) Remove the terminal plate.
only one or two numbers. Usually, 24 hours are required
(f) Remove the insulating blocks at the back of the
for the temperature to stabilize.
muffle carefully, laying out both layers so that they may
(d) A thermostat check can be made by using a
be installed in the same order that they were removed.
piece of wire as a temporary bridge across the two
Grasp lead wires. Gently work the muffle unit out.
thermostat terminals. If the compressor starts and runs
Remove the insulating sleeves from the muffle lead wire.
with the bridge, the thermostat is at fault and should be
(e) If the test lamp check shows power supply at the
(a) Replace the insulating sleeves over the wire.
Insert the muffle with the hole for the thermocouple
manual test set.
f. Troubleshooting. The operator should be
insulating blocks over the rear of the muffle.
guided by the following chart (table 3-6) in diagnosing
(b) Replace the terminal plate, drawing lead wires
and correcting operating difficulties.
(c) Attach leads to the terminals.
(d) Attach the thermocouple to the instrument in the
Inspect the thermocouple regularly for
base, making sure that each wire goes to the terminal
from which it has been removed. Replace metal air vent
Inspect the protection tube for leaks.
with spring in hole. Stand the furnace up. Open the hole
b. Cleaning. Keep the instrument free from
from inside of the muffle and insert the thermocouple (5,
accumulation of oil or moisture.
(e) Replace the loose insulation blocks.
c. Lubricating. Do not grease or lubricate any part
(f) Replace the backplate (6) and tighten three
of the unit.
3-13. Muffle Furnace.
On-Off switch and timer.
(a) Turn muffle furnace on its side and tag all wires
Inspect the thermocouple and muffle
Check the on-off switch and pilot light
and remove knob, remove attaching nut securing switch
and replace if necessary.
and timer assembly to lower oven chassis.