Heater Housing; O Verheat Sw Itch And C Ycling Sw Itch; Lockout Overheat Switch - Piper TWIN COMANCHE PA-30 Service Manual

13-62. HEATER HOUSING.
a. Clean inside and out with dry cleaning solvent, and inspect housing for round-
ness and dents. Straighten or reshape as necessary.
b. Replace all rubber grommets in the housing.
13-63.
FLAME DETECTOR SWITCH. Check bow spring to see if pressure of
quartz rod is causing it to bow up toward the top of the switch.
If the spring is
not bowed, but is in a straight position, the quartz rod is broken and must be re-
placed.
If such is the case, proceed as follows:
a.
Loosen the two switch mounting screws.
b. Remove the adjusting screw.
c.
Turn microswitch back on the bracket and remove the bow spring. Inspect
condition of the quartz rod.
d. If the quartz rod is broken or chipped on either end, it must be replaced.
If it is in good condition, replace it in the tube, turn the switch back into position
and reinstall the adjusting screw.
e. Back off the adjusting screw until the switch clicks, indicatingthat the micro-
switch has transferred.
f.
Turn the adjusting screw slowly in, until the switch just clicks again, to
determine point of transfer, then turn the screw exactly 3/4 turn past the trans-
fer point.
g. Hold the screws and tighten microswitch mounting nuts to lock switch se-
curely in place.
13-64.
OVERHEAT SWITCH AND CYCLING SWITCH. Visually inspect the cy-
cling switch, for damage and clean contacts by sliding a strip of clean bond paper
between the contacts.
Do not use a file or sandpaper, and do not attempt to bend
the contact arm.
These switches are adjusted at the factory and the adjustment
cannot be changed in the field. Replace switch if found defective.
13-65.
LOCKOUT OVERHEAT SWITCH.
a.
Connect wires to the two connector wires of the lockout overheat switch,
and suspend this assembly in an oven with an accurate thermometer. Provide a
test light or meter to indicate opening of the switch contacts. Press the reset
button of the switch.
b. Slowly raise the oven temperature
unul the switch contacts open. Note
temperature in the oven at the moment of switch operation. The switch must
open at a temperature
of 205 to 245
°
F. If not within limits, install anew switch.
This unit is not adjustable.
HEATING AND VENTILATING
^
Issued: 12/29/72
4 B20
PIPER TWIN COMANCHE SERVICE MANUAL