
5) When the call for heat is satisfied, the solenoid valve closes,
the flame goes out and the burner motor stops (after post purge
delay, if applicable).
6) The blower stops shortly after the burner. The delay depends
on the adjustments that were made on the electronic board that
controls the blower. Refer to Sections 2.11 and 2.12 above as
well as to the airflow tables 7 and 8 for more details.
Note: A detailed operating sequence of the oil burner is outlined in the
instructions provided with the burner.
3.3 CHECKS AND ADJUSTMENTS
3.3.1 Purging the oil line
Open the 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. Slowly close and
tighten the bleed screw. Once closed, the flame will light up.
3.3.2 Pressure adjustment
The oil pressure must be adjusted according to the Technical
Specifications of this manual. An adjustment screw and a connection
for a pressure gauge are located on the oil pump for that purpose. Also
refer to the burner instruction manual.
3.3.3 Combustion Check
IMPORTANT
The heat exchanger metal surfaces may have oil and the baffle
insulation also contains binders. These products will burn or
evaporate when the unit operates for the first time. Because
of this, the smoke reading may be inexact during the first
minutes of operation. Therefore, the unit must operate during
at least 60 minutes before taking any readings to adjust the
combustion quality. Let the unit cool down before making any
adjustments.
IMPORTANT
The combustion check verification MUST be performed after
the nozzle replacement or the burner cleaning. After these
manipulations, the combustion parameters are necessarily
modified. Refer also to the burner instruction manual.
1. Drill a test hole in the flue pipe, approximately 18 inches from
the furnace breech. Insert the smoke test probe into the hole.
For installation using a sidewall venting, use the orifice provided
on the breech plate;
2. From a cold start, let the unit operate for about 5 minutes;
3. Set the burner air setting until you have between 0 and 1 on the
Bacharach Scale (or a “trace”);
4. Take a CO2 sample at the same test location where the #1
smoke reading was taken and make note of it. Example: 13.8%
of CO2 or 2.5% of O2;
5. Adjust the burner air setting to obtain a CO2 reading 1.5% lower
(or a O2 reading 2.0% higher) than the reading associated with
the “trace” of smoke. Example: 12.3% of CO2 or 4.5% of O2;
6. This method of adjusting the burner will result in clean
combustion (Bacharach smoke scale between 0 and a trace)
and ensure the proper functioning of the system. The optimum
CO2 level is around 12% to 13% (or 3.5% to 5.0% of O2).
3.3.4 Draft Regulator adjustment
On chimney installations only, a barometric draft regulator (supplied
with the furnace) must be installed, in order to ensure proper draft
through the furnace. The barometric damper must be mounted with the
hinge pins in a horizontal position and the face of the damper vertical
for proper functioning (see instructions included with the damper.) After
the furnace has been firing for at least five minutes, the draft regulator
should be set to between -0.025" and -0.060" W.C.
3.3.5 Overfire pressure test
The overfire draft that is taken through the observation port, located
above the burner, is a measurement necessary to determine if there
is a blockage in the heat exchanger or the flue pipe. Refer to the
Technical Specifications in this manual for overfire pressure values. A
high pressure condition may be caused by excessive combustion air,
due to the air band being too wide open, or a lack of flue draft (chimney
effect) or some other blockage, such as soot in the secondary section
of the heat exchanger or the use of an oversize nozzle input or high
pressure pump.
3.3.6 Vent Temperature Test
1. After having adjusted the burner combustion, insert a
thermometer into the test hole in the breech pipe;
2. The total vent temperature should be between 204 and 302°C
(400 and 575°F). If not, check for improper air temperature rise,
pump pressure, nozzle size or a badly sooted heat exchanger.
CAUTION
Low flue gas temperature increases the risk of condensation.
Adjust the total temperature at or higher then 204°C (400°F) in
order for the heat exchanger warranty to remain in force.
3.3.7 Supply Air Temperature Rise Test
1. Operate the burner for at least 10 minutes;
2. Measure the air temperature in the return air plenum;
3. Measure the air temperature in the largest trunk coming off the
supply air plenum, just outside the range of radiant heat from
the heat exchanger. 0.3 m (12") from the plenum of the main
take-off is usually sufficient;
4. The temperature rise is calculated by subtracting the return air
temperature from the supply air temperature;
5. If the temperature rise is lower or exceeds the temperature
specified in Table 6, change to the next lower or higher blower
speed tap, until the temperature rise falls to the target. If the
excessive temperature rise cannot be increased or reduced by
changing fan speed, investigate for ductwork obstructions, dirty
or improper air filter, improper firing caused by improper pump
pressure or nozzle sizing.
3.3.8 Limit control check
After operating the furnace for at least 15 minutes, restrict the return
air supply by blocking the filters or the return air register and allow the
furnace to shut off on High Limit. The burner will shut off but the blower
will continue to run.
Remove the obstruction and the burner should restart after a few
minutes. The time required for the restart also depends on the
adjustment of the blower “OFF” delay.
3.3.9 Restart after Burner Failure
1. Set the thermostat lower than room temperature;
2. Press the reset button on the burner primary control (relay);
3. Set the thermostat higher than room temperature;
4. If the burner motor does not start or ignition fails, turn off
the disconnect switch and CALL A QUALIFIED SERVICE
TECHNICIAN.
CAUTION
Do not attempt to start the burner when excess oil has
accumulated, when the furnace is full of vapour or when the
combustion chamber is hot.
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