44
START-UP PROCEDURES
This furnace is equipped with a silicon
carbide hot surface ignition (HSI) device.
Each time the room thermostat calls for
heat, the HSI lights the main burners
directly See the lighting instructions on
the furnace.
TO START THE FURNACE
1. Remove the burner compartment
control access door.
2.
IMPORTANT:
Be sure that the
manual gas control has been in the
“OFF” position for at least five
minutes. Do not attempt to manually
light the main burners.
3. Turn off the furnace electrical power
and set the room thermostat to its
lowest setting.
4. Turn the gas control knob to the
“ON” position.
5. Replace the burner compartment
control access door.
6. Turn on the furnace electrical power.
7. Set the room thermostat to a point
above room temperature to light the
main burners.
8. After the burners are lit, set the room
thermostat to a desired temperature.
TO SHUT DOWN
THE FURNACE
1. Set the room thermostat to its lowest
setting.
2. Remove the burner compartment
control access door.
3. Shut off the gas to the main burners
by turning the gas control knob to
the “OFF” position. See Figure 36.
SHOULD OVERHEATING OCCUR
OR THE GAS SUPPLY FAIL TO
SHUT OFF, CLOSE THE MANUAL
GAS VALVE FOR THE APPLIANCE
BEFORE SHUTTING OFF THE
ELECTRICAL SUPPLY. FAILURE TO
DO SO CAN CAUSE AN EXPLOSION
OR FIRE RESULTING IN PROPERTY
DAMAGE, PERSONAL INJURY OR
DEATH.
SEQUENCE OF OPERATION
Honeywell or UTEC Integrated
Controls with Hot Surface Ignition.
1. Each time the thermostat contacts
close, the induced draft blower
(inducer) begins a prepurge cycle.
2. The air proving negative pressure
switch(es) closes.
3.
30 seconds after the pressure
switch(es) close, the hot surface
igniter heats for 30 seconds
to full
temperature. The induced draft
blower operates for the complete
heating cycle.
4. After the 30-second igniter warm up,
the gas valve opens for a
9-second trial for ignition.
5. The igniter lights the gas burners
and
stays energized for the first 8
seconds after the gas valve
opens.
6. 8 seconds after the gas valve opens
the remote flame sensor must
prove flame ignition for
one
second
using the process of flame
rectification. If the burners don’t light,
the system goes through another
ignition sequence. It does this up to
four times.
7. The main blower starts
approximately 20 seconds after the
burners ignite.
8. When the thermostat cycle ends, the
gas valve closes, the burners go
out, the induced draft blower stops
after
a 5-second post-purge,
and
the negative pressure switch(es)
open.
9. The main blower continues until
timed off by the setting on the
integrated furnace control board.
Sequence if the system doesn’t light
or doesn’t sense flame:
1. On a call for heat, the control runs
the inducer for 30 seconds to
prepurge.
2. After the 30-second prepurge, the
hot surface igniter heats for 30
seconds. The inducer continues to
run.
3. After the 30-second igniter warm up,
the gas valve opens for a
9-second trial for ignition. The
inducer continues and the igniter
stays energized.
4. If flame is not sensed during the
ninth second after the gas valve
opens, the gas valve closes, and the
igniter de-energizes.
5. After a 30 second inter-purge, the
igniter heats for 30 seconds. After
30 seconds, the gas valve opens for
9 seconds. If no flame is sensed, it
closes the gas valve, the igniter de-
energizes.
Both the inducer and
main blower operate for 180
seconds.
6. It retries up to four times. At the end
of the last try, the inducer stops
immediately.
The system is in
“soft” lock out.
7. The above sequence will repeat
after a one hour delay. It will
continue repeating until ignition is
successful or the call for heat is
terminated.
8.
To reset the lock out, make and
break power either at the
thermostat or at the unit
disconnect switch for 5 to 10
seconds.
It then goes through
another set of trials for ignition.
UTEC or Johnson Controls Direct
Spark Ignition
1. Each time the thermostat contacts
close, the induced draft blower
(inducer) begins a prepurge cycle.
2. The air proving negative pressure
switch(es) closes.
3.
30 seconds after the pressure
switch(es) close, the spark
igniter energizes.
The induced
draft blower operates for the
complete heating cycle.
4. After the spark igniter energizes,
the gas valve opens for a 8
second trial for ignition.
5. The igniter lights the gas burners.
6. After the gas valve opens
the
flame sensor must prove flame
ignition for
one second
using the
process of flame rectification. If the
burners don’t light, the system
goes through another ignition
sequence. It does this
up to four
times.
7. The main blower starts 20 seconds
after the burners ignite.
8. When the thermostat cycle ends,
the gas valve closes, the burners
go out, the induced draft blower
stops after
a 5-second post-
purge,
and the negative pressure
switch(es) open.
9. The main blower continues until
timed off by the setting on the
integrated furnace control board.
Sequence if the system doesn’t
light or doesn’t sense flame:
1. On a call for heat, the control runs
the inducer for 30 seconds to pre-
purge.
2. After the 30-second pre-purge, the
spark igniter energizes. The
inducer continues to run.
3. After the spark igniter energizes,
the gas valve opens for a 8-
second trial for ignition. The
inducer continues and the igniter
stays energized.
4. If flame is not sensed within 8
seconds after the gas valve opens,
the gas valve closes, and the
igniter de-energizes.
5. After a 30-second inter-purge, the
igniter is energized, the gas valve
opens for 8 seconds. If no flame is
sensed, it closes the gas valve, the
igniter de-energizes.
Both the
main blower and the inducer
operate for 180 seconds before
the next ignition trial.
6. It retries up to four times. At the
end of the last try, the inducer
stops. The system is in “soft”
lockout.
7. The above sequence will repeat
after a one hour delay. It will
continue repeating until ignition is
successful or the call for heat is
terminated.
8.
To reset the lock out, make and
break power either at the
thermostat or at the unit
disconnect switch for 5 to 10
seconds.
It then goes through
another set of trials for ignition.
!
WARNING
Summary of Contents for RGRA SERIES
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