9
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. Each burn cycle should be 3 minutes in duration. The exhaust
will have a pungent odour and produce a white cloud of steam.
2.2.4) Perform the smoke / CO
2
test
1.
On chimney installations, pierce a test hole in the smoke pipe
near the furnace breech;
2.
Starting with a zero smoke reading, gradually reduce the burner
air setting until just a trace of smoke results (#1 on the
Bacharach Scale);
3.
Take a CO
2
sample at the same test location where the smoke
sample was taken. Note the CO
2
reading associated with the #1
smoke condition;
4.
On chimney vented installations, adjust the burner air setting to
obtain a CO
2
reading 1% lower than the reading associated with
the #1 smoke.
2.2.5) 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; 12 inches 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,
change to the next higher blower speed tap until the temperature
rise falls to that 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,
or overfiring caused by excessive pump pressure, or improper
nozzle sizing;
6.
Check and adjust all controls in accordance with the
manufacturer’s instructions. The temperature rise between
return plenum and supply plenum should be approximately 70 to
80
o
F (21 to 27
o
C).
2.2.6) Vent temperature test
1.
Place a thermometer in the test hole located in the breech pipe.
2.
The vent temperature should be between 204 and 302
o
C (400
and 575
°
F). If not, check for improper air temperature rise,
pump pressure, nozzle size, or for a badly sooted heat
exchanger.
2.2.7) Fan Limit adjustment
FAN LIMIT
:
The temperature adjustment must correspond to the
following table:
TABLE 3
MODEL
TEMPERATURE
CCC-A
200
o
F
93
o
C
MBPF-A
150
o
F
66
o
C
MBP1-A
180
o
F
82
o
C
MBP2-A
220
o
F
104
o
C
MBP-U
180
o
F
82
o
C
