53
6. Remove the outdoor thermostat from the outside coil.
7. Carefully slide thermostat wiring through the center parti-
tion. When replacing, be sure all holes in the center parti-
tion are properly sealed with Permagum.S-5 Outdoor Coil
Thermostat or Thermistor (Switchover Thermostat)
Checking Switchover Thermostat
1. With power off, remove the switchover thermostat leads
from the circuit board.
2. Check, the switchover thermostat for continuity . Below
25° ±5°F the thermostat should read open. Above 60° +
6°F the thermostat should always read closed. Between
25° ±5°F and 50° ±5°F the thermostat will read open if coil
temperature has been below 25° ±5°F and not yet reset by
going above 50°±5°F otherwise the thermostat will read
closed
3. Replace the switchover thermostat if it does not test as
above.
4. The "C-K" models with the blue thermistor on the outdoor
coil, will lock out the compressor at 24°. The compressor
will re-engage when the coil temperature has warmed up
to 33°.
See Thermistor OHMS values in the chart on
page 53.
S-6 HEATER ASSEMBLY
1. Remove front cover.
2. Remove the two mounting screws holding the screen above
the indoor coil in place. Remove the screen. (Be sure to
slide the top of the screen between the top flange and
chassis when reassembling.)
3. Remove the two screws holding the blower inlet panel in
place. Lift the blower inlet panel out of the unit and set
aside.
4. Remove heater from the blower inlet panel by removing the
two #8 mounting screws.S-6 Heater Assembly
All heaters produced
May of 2004 have a
manual reset limit.
5. All heater assembly components are now accessible.
6. All heaters manufactured after May of 2004 have a manual
reset limit on the heater.
See image at bottom of previ-
ous column
.
Checking Heater Assembly
1. With power off to the unit and heater, remove the heaters
in question and visually inspect the element for broken
condition.
2. Remove the wires from the element and check for continu-
ity through the heater. If there is no continuity the heater
needs to be replaced.
S-7 DRAIN PAN VALVE (HEAT PUMP MODELS
ONLY)
1. Remove the chassis from the wall sleeve.
2. Remove the mounting screw and remove the drain valve.
The drain pan perates to remove condensate from base pan.
This is a thermal operated device that opens at 40°F and closes
at 60°F.
Checking Operation of the Drain Valve
1. Cool the valve to 40°F or below and the plunger should
open.
2. Warm the valve up to 60°F and the plunger should close.
S-10A FUSE REPLACEMENT
Control Board
The above boards fuse should be removed form the holder and
checked with a ohm meter. Continuous ohms indicate a good
fuse on reading indicates a open fuse replace fuse. The fuse
can only be replaced once. After the first replacement, the unit
must be checked for cause of repeated failure.
Ranco control boards have two fuses in a plastic holder. If the
fuse is blown, turn the holder over and insert the new fuse. If
the unit still does not operate check the fuse with a ohm meter.
The fuse can only be replaced once. After the first replace-
ment, the unit must be checked for cause of repeated failure.
"G" & "K" model boards do not have fuses.
SERVICING
