Sequence Of Operation - Riello 40-Bf Side-Wall Venting; Sequence Of Operation - Beckett Afg And Riello 40-F, Chimney Venting; Sequence Of Operation Vtk Venting System; Checks And Adjustments - Dettson OLR105A12D Mode D'emploi

Thermostat is satisfied:
9. SPDT relay contacts open, solenoid valve closes,
burner fan motor post-purges the combustion chamber
and vent for a pre-set time (15 seconds.). The ignition
transformer also continues to spark for this time period;
10. During the post-purge cycle, the Fan-Limit Control cools
down to the factory set point of 32°C (90°F) and the
circulating air blower turns off.
3.2.2 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 15 seconds (5"
breech 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.
3.2.3 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;
3.2.4 Sequence of operation, VTK 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 15 seconds 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.
3.3

CHECKS AND ADJUSTMENTS

3.3.1

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 3 to 5.
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