Supply Air Temperature Rise Test - Walter Wilson LOW-BOY OLV154F20A Guide D'installation Et Manuel Du Propriétaire

From a cold start, let the unit operate for about 5 minutes;
2.
Set the burner air setting until you have between 0 and 1
3.
on the Bacharach Scale (or a ''trace'');
Take a CO sample at the same test location where the
4.
2
''trace'' of smoke reading was taken and make note of it.
Example: 13.8% of CO
Adjust the burner air setting to obtain a CO
5.
lower (or a O reading 2.0% higher) than the reading
2
associated with the ''trace'' of smoke. Example: 12.3% of
CO or 4.5% of O ;
2 2
This method of adjusting the burner will result in clean
6.
combustion (Bacharach smoke scale between 0 and a
trace) and ensure the proper functioning of the system.
The optimum CO level is around 12% to 13% (or 3.5% to
2
5.0% of O ).
2
D R
3.3.4
RAFT EGULATOR 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.
O
3.3.5
VERFIRE 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.
V T
3.3.6
ENT EMPERATURE
After having adjusted the burner combustion, insert a
1.
thermometer into the test hole in the breech pipe;
The total vent temperature should be between 204 and
2.
302°C (400 and 575°F). If not, check for improper air
temperature rise, pump pressure, nozzle size or a badly
sooted heat exchanger.
proper flue pipe sizing.
CAUTION
Low flue gas temperature increases the risk of
condensation. Adjust the total flue gas temperature
at or higher then 204°C (400°F) in order for the heat
exchanger warranty to remain in force.
S T
3.3.7
UPPLY AIR EMPERATURE
1. Operate the burner for at least 10 minutes;
2. Measure the air temperature in the return air plenum;
3. Measuring 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;
or 2.5% of O ;
2 2
reading 1.5%
2
T
EST
Also refer to section 2.5 for
R T
ISE EST
4. The temperature rise is calculated by subtracting the
return air temperature
temperature;
5. If the temperature rise is lower or exceeds the
temperature specified in Table 7, p. 13, 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,
obstructions, dirty or improper air filter, improper firing
caused by improper pump pressure or nozzle sizing.
L C
3.3.8
IMIT ONTROL
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.
R
3.3.9
ESTART 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.
10
from the supply
investigate for ductwork
C
HECK
air