AERCO KC1000 Heater 2002 - Manual (Page 31)

INITIAL START-UP
4-3
1. Open the supply and return valves to the unit
and ensure that the system pumps are
running.
2. Open the gas supply valve(s) to the unit.
3. If a lockup style regulator is installed as a
gas supply regulator, adjust the gas supply
until a reading of 12” W.C. static pressure is
obtained.
4. Set the
ON/OFF switch in the OFF position.
Turn on AC power to the unit. The display
will show LOSS OF POWER and the time
and date.
5. Set the unit to the Manual Mode by pressing
the
AUTO/MAN switch. A flashing Manual
Fire Rate message will be displayed with the
present rate in %. Also, the
MANUAL LED
will light.
NOTE:
For a review of control panel operating pro-
cedures
, see Section 3.
6. Adjust the rate to 0% by pressing the
▼
arrow key.
7. Set the
ON/OFF switch to the ON position.
8. Change the firing rate to 25% using the
▲
arrow key. This will put the unit into the
starting sequence.
NOTE:
On initial start-up, or return to service from a
fault condition, the unit will remain at a 29% firing
rate for two-minutes, although the control signal
may indicate a greater input.
9. Following the warm-up period, increase the
firing rate in 20% increments while monitor-
ing the gas pressure after every increase. If
gas pressure dips below 8.5” W.C. for FM
gas trains and 8.9” for IRI gas trains at any
input percentage, stop and raise the pres-
sure. Once 100% is reached, adjust the gas
pressure for 8.5” W.C. or 8.9” W.C.
NOTE:
If 8.5” W.C. for FM gas trains or 8.9” W.C. for IRI
gas trains cannot be obtained at the 100% firing
rate, it will be necessary to stop calibration and
contact the local AERCO representative in your
area. Running the unit on insufficient gas
pressure will void the warranty.
10. Once 8.5” W.C. or 8.9” W.C. is set at the
100% level change the firing rate to 30%.
Insert the combustion analyzer probe into
the stack.
NOTE:
Always go to a percentage of firing rate from the
same direction, (i.e., 100% to 30% or 30% to
20%). Whenever going to a firing rate from
below (i.e., 20% to 30%), first go above then
back down to the desired firing rate. This is
necessary due to hysteresis in the air/fuel
stepper motor. Hysteresis causes the air/fuel
valve to stop in a slightly different position if the
firing rate percentage is approached from below
or above. This results in a difference in oxygen
readings for the same firing rate percentage
causing unnecessary recalibration
.
11. Allow enough time for the combustion
analyzer to settle. Compare the measured
oxygen level to the oxygen range for intake
air temperature in Table 1.
Table 1
Combustion Oxygen Levels for a 30%
Firing Rate
Inlet Air
Temp
Oxygen
(+0.2/-1.0)
Carbon
Monoxide
-20°F 7.5 % <50 ppm
0°F 7.3 % <50 ppm
10°F 7.2 % <50 ppm
30°F 6.8 % <50 ppm
50°F 6.4 % <50 ppm
60°F 6.2 % <50 ppm
70°F 6.0 % <50 ppm
80°F 5.8 % <50 ppm
90°F 5.6 % <50 ppm
100°F 5.4 % <50 ppm
12. If the measured oxygen level is within the
range in Table 1, no adjustment is neces-
sary. Proceed to step 17.
13. If the measured oxygen level is below the
range in Table 1, rotate the differential
regulator adjustment tool counterclockwise
1/4 to 1/2 revolution to decrease gas flow.
14. Wait for the combustion analyzer to settle,
then compare the new oxygen reading to
Table 1. Repeat adjustment until oxygen is
within the specified range.