Bryant 581J-17-28 Service And Maintenance Instructions page 38

Supply Pressure Switch
The LP conversion kit includes a supply low pressure
switch. The switch contacts (from terminal C to terminal
NO [Normally Open]) will open the gas valve power
whenever the supply line pressure drops below the
setpoint. See Figs. 47 and 48. The switch, HK02LB008,
opens contacts on pressure "fail" at 7.2 ±0.70 in. wg.
Contacts close on pressure rise above 10.2 in. wg. If the
low pressure remains open for 15 minutes during a call for
heat, the IGC circuit will initiate an 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.
Limit Switch
Remove the blower access panel. The Limit Switch is
located on the fan deck for sideshot units and on the
vestibule plate for downshot units. SeeFig 49.
581J*D08 only
GAS VALVE
Fig. 47 − LP Low Pressure Switch (Installed)
IGC
J2-11
J2-12
W2
Fig. 48 − LP Supply Line Low Pressure Switch Wiring
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-
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 the blower wheel every fall and
periodically during the heating season. For the first
heating season, inspect the blower wheel bi−monthly to
determine proper cleaning frequency.
To access the burner section, open the heater access door
below the indoor fan panel.
To inspect the blower wheel, shine a flashlight into the
C08238
draft hood opening. If cleaning is required, remove the
motor and wheel as follows:
1. Remove the seven screws attaching the induced−draft
2. The blower wheel can be cleaned at this point. If ad-
3. Remove the blower from the motor shaft by loosening
4. Remove the motor by removing the four screws that
LP LOW PRESSURE
SWITCH
5. Remove the nuts that hold the motor to the mounting
C08238A
6. To reinstall, reverse the procedure outlined above.
38
LP LPS
BRN C
IGC
GRA
TSTAT
PNK
sembly according to directions in the Combustion−
Air Blower section. See Fig. 49.
motor housing to the vestibule plate. See Fig. 49.
ditional cleaning is required, continue with Steps 3
through 5.
two setscrews.
hold the motor to the mounting plate. Remove the
motor cooling fan by removing one setscrew.
plate.
BRN
NO
C
MGV
C08285