Carrier 48TC 04 Series, Service And Maintenance Instructions

Page: 47 / 152

47
Table 12 – Liquid Propane Supply Line Pressure
Ranges
UNIT MODEL UNIT SIZE MIN MAX
48TC
04---14
11.0 in. wg
(2740 Pa)
NA
13.0 in. wg
(3240 Pa)
NA
16
Manifold pressure for LP fuel use must be adjusted to
specified range. Follow instructions in the accessory kit to
make initial readjustment.
Table 13 – Liquid Propane Manifold Pressure Ranges
UNIT SIZES LOW FIRE HIGH FIRE
48TCD
48TCS
04---07
08---09
NA
10.0 in. wg
(2490 Pa)
12---14
5.7
(1419 Pa)
16
6.6.
(1643 Pa)
48TCE
48TCR
04---07
5.0 +
(1245 Pa)
10.0 in. wg
(2490 Pa)
08---09
5.7
(1419 Pa)
12---14
5.7
(1419 Pa)
16
6.6
(1643 Pa)
48TCF
48TCS
05---07
5.0
(1245 Pa)
10.0 in. wg
(2490 Pa)
08---14
5.0 +
(1245 Pa)
16
6.6.
(1643 Pa)
48TCL
48TCM
48TCN
04---06 NA
+: Size 04 only
NA : Not Available
Supply Pressure Switch —
The LP conversion kit
includes a supply low pressure switch. The switch
contacts (from terminal C to terminal NO) will open the
gas valve power whenever the supply line pressure drops
below the setpoint. See Fig. 58 and Fig. 59. If the low
pressure remains open for 15 minutes during a call for
heat, the IGC circuit will initiate a Ignition Fault (5
flashes) lockout. Reset of the low pressure switch is
automatic on rise in supply line pressure. Reset of the IGC
requires a recycle of unit power after the low pressure
switch has closed.
C08238
Fig. 58 -- LP Low Pressure Switch (Installed)
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.
PNK W2
TSTAT
GRA
BRN
IGC
J2-12
IGC
J2-11
BRN
C
NO
MGV
C
LP LPS
C08285
Fig. 59 -- LP Supply Line Low Pressure Switch Wiring
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. 60.
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 wheel every fall and
periodically during heating season. For the first heating
season, inspect blower wheel bi--monthly to determine
proper cleaning frequency.
To access burner section, slide the sliding burner partition
out of the unit.
To inspect blower wheel, shine a flashlight into draft hood
opening. If cleaning is required, remove motor and wheel
as follows:
1. Slide burner access panel out.
2. Remove the 7 screws that attach induced--draft mo-
tor housing to vestibule plate. See Fig. 60 and 61.
3. The blower wheel can be cleaned at this point. If ad-
ditional cleaning is required, continue with Steps 4
and 5.
4. To remove blower from the motor shaft, remove 2
setscrews.
5. To remove motor, remove the 4 screws that hold the
motor to mounting plate. Remove the motor cooling
fan by removing one setscrew. Then remove nuts that
hold motor to mounting plate.
6. To reinstall, reverse the procedure outlined above.
48TC