
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 Tech-
nical 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 oper-
ates 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 ad-
just the combustion quality. Let the unit cool down be-
fore making any adjustments.
IMPORTANT
The combustion check verification MUST be per-
formed 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. the burner air setting to obtain a CO2 reading 1.5%
lower (or a O2 reading 2.0% higher) than the read-
ing 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 be-
tween 0 and a trace) and ensure the proper func-
tioning 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 regula-
tor (supplied with the furnace) must be installed, in order
to ensure proper draft through the furnace. The baro-
metric 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 neces-
sary to determine if there is a blockage in the heat ex-
changer or the flue pipe. Refer to the Technical Specifi-
cations in this manual for overfire pressure values. A high
pressure condition may be caused by excessive combus-
tion air, due to the air band being too wide open, or a
lack of flue draft (chimney effect) or some other block-
age, 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 im-
proper air temperature rise, pump pressure, nozzle
size or a badly sooted heat exchanger.
CAUTION
Low flue gas temperature increases the risk of con-
densation. 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;
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