Carrier 48HC D17 Series Service And Maintenance Instructions page 43

Limit Switch
Remove blower access panel. Limit switch is located on
the fan deck for sideshot units and on the vestibule plate
for downshot units. See Fig. 50.
48HC*D08 only
GAS VALVE
All 48HC*D except *D08
Fig. 51 - - LP Low Pressure Switch (Installed)
LP LPS
IGC
BRN C
J2-11
IGC
J2-12
TSTAT
W2 PNK
Fig. 52 - - LP Supply Line Low Pressure Switch Wiring
C09396
LP LOW PRESSURE
SWITCH
C08238A
BRN
NO
C
MGV
GRA
C08285
This switch also prevents operation when the propane tank
level is low which can result in gas with a high
concentration of impurities, additives, and residues that
have settled to the bottom of the tank. Operation under
these conditions can cause harm to the heat exchanger
system. Contact your fuel supplier if this condition is
suspected.
Flue Gas Passageways
To inspect the flue collector box and upper areas of the
heat exchanger:
1. Remove the combustion blower wheel and motor as-
sembly according to directions in Combustion- - Air
Blower section. See Fig. 53.
2. Remove the flue cover to inspect the heat exchanger.
3. Clean all surfaces as required using a wire brush.
Combustion- -Air Blower
Clean periodically to assure proper airflow and heating
efficiency. Inspect blower
periodically during heating season. For the first heating
season, inspect blower wheel bi- - monthly to determine
proper cleaning frequency.
To access burner section, open the heater access door
below the indoor fan panel.
To inspect blower wheel, shine a flashlight into draft hood
opening. If cleaning is required, remove motor and wheel
as follows:
1. Remove the seven screws attaching the induced- - draft
motor housing to the vestibule plate. See Fig. 53.
2. The blower wheel can be cleaned at this point. If ad-
ditional cleaning is required, continue with Steps 3
through 5.
3. Remove the blower from the motor shaft, by
loosening two setscrews.
4. Remove the motor by removing the four screws that
hold the motor to mounting plate. Remove the motor
cooling fan by removing one setscrew.
5. Remove the nuts that hold the motor to the mounting
plate.
6. To reinstall, reverse the procedure outlined above.
43
wheel every fall and