Restart After Burner Failure; Combustion Chamber Curing; Smoke / Co Test; Perform The Supply Air Temperature Rise Test - Dettson OLR105A12D Mode D'emploi

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 3 to 5 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.
3.3.2

Restart after burner failure

1. Set thermostat lower than the room temperature;
2. Press the reset button on the burner primary control
(relay);
3. With side-wall venting and Riello burner, set thermostat
higher than the room temperature for 10 seconds, then
set lower than room temperature. This will start pre-
purge cycle. Repeat twice;
4. Set thermostat higher than the room temperature;
5. 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 very hot. Always keep
the supply valve closed if the burner is shut down for an
extended period of time.
3.3.3

Combustion chamber curing

Some moisture and binders remain in the ceramic
combustion chambers after fabrication. It is important to
clear the chamber of this residue before testing. If you
smoke test before curing, the instrument may become
damaged. To cure the chamber, run the unit for 3
consecutive cycles, with 3 minutes of elapsed time in
between each cycle. The burner must operate for about 3
minutes per cycle. The exhaust will have a pungent odour
and produce a white cloud of steam.
3.3.4 Smoke / CO test
2
1. On chimney installations, pierce a test hole in the
smoke pipe 18'' above the furnace breech. On side-wall
vented installations, remove the threaded cap from the
extended test pipe that is welded into the 4-bolt breech
plate. Insert the smoke test instrument probe into the
open hole;
2. From a cold start, let the unit operate during 5 to 10
minutes;
3. Set the burner air setting until just a trace of smoke
results (#1 on the Bacharach scale);
4. Take a CO sample at the same test location where the
2
#1 smoke reading was taken and make note of it.
Example: 13.8% of CO
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 #1 smoke. Example: 12.3%
or CO2 or 4.5% of O2;
6. This method of adjusting the burner will result in clean
combustion and ensure the proper functioning of the
system.
or 2.5% of O ;
2 2
3.3.5

Perform the supply air temperature rise test

1. Operate the burner for at least 10 minutes;
2. Measure the temperature of the air in the return air
plenum;
3. Measure the temperature of the air in the largest trunk
coming off the supply air plenum, just outside the range
of radiant heat coming off the heat exchanger; 30 cm
(12") away from the plenum on 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 exceeds the temperature
specified in Tables 4.1 to 4.3, change to the next higher
blower speed tap until the temperature rise falls to this
temperature or below. If the excessive temperature rise
cannot be reduced by increasing fan speed, investigate
for ductwork restriction(s), dirty or improper air filter,
overfiring caused by excessive pump pressure, or
improper nozzle sizing.
3.3.6

Vent temperature test (chimney installation)

1. After 5 to 10 minutes of operation, place a thermometer
in the test hole located in the breech pipe;
2. The 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 for a
badly sooted heat exchanger.
3.3.7

Overfire pressure test procedure

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.
3.3.8

Fan-Limit adjustment

Modification of the "FAN ON" and "HI" limit settings on the
Fan-Limit can cause a malfunctioning of the furnace and
result in premature wear of the heat exchanger.
Please refer to the different adjustment values in Figure
3.
Modification of the factory set limits will void the
warranty.
3.3.9

Fan-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.
11
CAUTION