Sequence Of Operation - Napoleon NBM030S2A Installation And Operating Instructions Manual

SHOULD OVERHEATING OCCUR OR THE GAS BURNERS FAIL TO SHUT OFF, CLOSE THE
MANUAL GAS VALVE FOR THE FURNACE BEFORE SHUTTING OFF THE ELECTRICAL
POWER TO THE FURNACE. FAILURE TO DO SO CAN CAUSE AN EXPLOSION OR FIRE
RESULTING IN PROPERTY DAMAGE, PERSONAL INJURY OR LOSS OF LIFE.
BEFORE RESTARTING THE FURNACE, CHECK ALL PLASTIC VENTS AND WIRES FOR

17.3 SEQUENCE OF OPERATION

1. Room temperature drops causing the room thermostat call for heat by connecting "W" to "R". The control
verifi es the limit switch is closed and the pressure switch(s) are open. The control energizes the exhauster
motor and waits for the pressure switch(s) to close. The exhauster remains energized for a 15 second pre-
purge period. If the pressure switch(s) do not close within 60 seconds, the control will fl ash "2" on the Red
Status LED, and de-energize the exhauster for 60 minutes.
2. When the 15 second pre-purge time has elapsed, the control energizes the HSI output for a 5 second
warm-up period (10 seconds on retries). The control energizes the gas valve. 4 seconds after the gas
is energized, the control de-energizes the HSI output and leaves the gas energized another 1 second
for fl ame proving. If fl ame is present at the end of trial for ignition time, the control leaves the gas valve
energized, exhauster on, and begins heat blower on delay.
3. Blower on delay time begins when the gas valve is energized.
4. Blower off delay is handled by the control board. When the thermostat "W" call ends, the control de-
energizes the gas valve, and starts the blower off delay period.
IN THE EVENT OF FLAME FAILURE:
If fl ame is lost, the control de-energizes the gas valve within 2 seconds, continues running the exhauster
motor, and begins timing the inter-purge delay. The indoor blower motor will be energized and/or remain
energized on heat speed for the delay off time. When the inter-purge delay is over, the control will re-cycle up
to 5 fl ame losses (4 re-cycles) within a single call for heat before going into lockout. The control fl ashes "8" on
the Red LED if lockout is due to too many fl ame dropouts (1 hour lockout).
WARNING
! !
DAMAGE.
45
H3.24
H21.3.1A
W415-1117 / F / 11.02.17
IOM