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2.2.2
Sequence of operation
Riello 40-BF Side-wall Venting
1.
Normally open contact (W-R) on SPDT relay closes when
thermostat calls for heat;
2.
Burner motor starts. The burner motor fan pre-purges the
combustion chamber and vent for 10 seconds, establishing the
combustion air pattern. During this time the solenoid valve
holding coil pressure will be approximately 100 psig;
3.
After the pre-purge period, the solenoid valve opens, allowing oil
to flow through the nozzle. At the same time, the burner motor
ignition coil produces spark;
4.
The ignition transformer spark ignites oil spray;
5.
Cad cell senses flame and burner continues to fire. Ignition
transformer ceases sparking;
6.
After Fan-Limit Control heats up to the factory set point, the
circulating air blower starts;
7.
The circulating air blower and burner motor remain on until the
thermostat is satisfied. Also, the solenoid valve remains open;
Thermostat is satisfied:
8.
Relay contacts opens, solenoid valve closes, and the burner fan
motor post-purges the combustion chamber and vent for a pre-
set time of up to 6 minutes (5" breach model only);
9.
During the post-purge cycle, the Fan-Limit Control bi-metal cools
down to the factory set point of 32°C (90°F), and the circulating
air blower turns off.
NOTE: With burner relay contact open, the Riello 40-
BF will post-purge when 115 volt power is applied to the
burner.
2.2.3
Sequence of operation - Beckett AFG and
Riello 40-F, chimney venting
1.
On the AFG burner, the T-T terminals have to be jumpered on
the primary control of the burner;
2.
Normally open contact (W-R) closes when thermostat calls for
heat;
3.
Burner motor starts. The burner motor fan pre-purges the
combustion chamber and vent for 10 to 15 seconds, establishing
the combustion air pattern. After the pre-purge period, the
solenoid valve opens, allowing oil to flow through nozzle. At the
same time, the burner motor ignition coil produces a spark;
4.
Spark ignites oil droplets;
5.
Cad cell senses flame and burner continues to fire. Ignition
transformer ceases sparking (Riello R40-F);
6.
After Fan-Limit Control heats up to the factory set point, the
circulating air blower starts;
7.
The circulating air blower and burner motor remain on until the
thermostat is satisfied;
Thermostat is satisfied:
8.
Relay contacts open, solenoid valve closes, burner fan motor
shuts down and the ignition transformer ceases sparking;
16
2.2.4
Sequence of operation
DV-2000™ Venting system
Normal operation
1.
Before a call for heat, the contacts of the pressure switch are
closed;
2.
When the room thermostat calls for heat, the normally open
contact W-R closes, the burner blower starts and creates suction
in the intake piping circuit and pressure in the vent piping circuit;
3.
The differential pressure set point of the pressure switch is not
exceeded and the thermostat circuit remains closed until the call
for heat has ended.
Abnormal operation
Start-up
1.
When the room thermostat calls for heat, the normally open
contact W-R closes, the burner blower starts and creates suction
in the intake piping circuit and pressure in the vent piping circuit;
2.
If there is a blockage in the intake or vent openings to cause a
pressure differential beyond the set point of the pressure switch,
then the thermostat circuit is opened and the burner will go into a
2 minutes post-purge and then shut down;
3.
Once the burner blower shuts down, after the post-purge, the
pressure switch contacts will re-close. If the call for heat remains,
the burner will re-start. If the blockage still exists, the thermostat
is again opened, and the burner post-purges again. The post-
purge function thus becomes an inherent anti-short cycling
device;
4.
The unit will essentially go into a continuous re-cycling/post-
purge mode with no heat being supplied to the dwelling, which
will prompt a service call;
5.
If, during the re-cycling/post-purges, the blockage of the terminal
is removed, the burner will immediately fire up at the end of the
current post-purge cycle.
During operation
If the terminal vent or intake openings become blocked to the point
where the set point of the pressure switch is exceeded during a firing
cycle, the flame will shut down and the burner will go into the indefinite
recycling post-purge mode as described above, until the blockage is
removed.
2.3
CHECKS AND ADJUSTMENTS
2.3.1
General
During initial start-up and subsequent yearly maintenance calls, the
furnace must be thoroughly tested.
Open the oil bleed port screw and start the burner. Allow the oil to
drain into a container for at least 10 seconds. The oil should flow
absolutely free of white streaks or air bubbles to indicate that no air is
being drawn into the suction side of the oil piping and pump. Then
slowly close and tighten the bleed screw. Fire the burner. Adjust the oil
pressure as indicated in Tables 4.1 to 4.3.
IMPORTANT
The burner must be put in operation for at least 10
minutes before any test readings are taken. For new
installations, set up the burner to the settings in Tables
4.1 to 4.3 before firing. These are rough adjustments
but they will ensure that the burner will start and run
smoke-free in advance of the final adjustments to be
made.
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