AERCO KC Standard to Low NOx Convertion Instructions - Manual (Page 39)

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5.4 Combustion Calibration For Units With Digital (CCC) Control Systems
The Combustion Calibration procedures for KC1000 Boilers or Water Heaters equipped with older
style Digital (CCC) Control Systems differ from those used for C-More or Modular Control Systems.
The primary difference is that the combustion readings are checked at different low and mid-range fire
rates. In addition, the Control Panel display shows the manual fire rate in % for KC Boilers and in
Volts (1.0 to 5.0) for KC Water Heaters. Using the following procedures will minimize readjustment of
combustion.
NOTE
For a review of the control panel operating procedures for the installed control
system, refer to Section 3 of GF-101 (Water Heater) or GF-102 (Boiler).
1. Open the supply and return valves to the unit and ensure that the system pumps are running.
Open the gas supply valve(s) to the unit.
2. 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.
3. Set the unit to the MANUAL mode.
4. With the display showing the Power Level, rotate the MANUAL adjustment to display 25%
(Boiler) or 2.0 volts (Water Heater).
5. Press the green ON button if the unit is not already ON.
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.
In the following steps and Tables, firing rates for KC1000 Boilers are shown in
% and the corresponding firing rates for Water Heaters are shown in
parentheses in volts (V).
6. Following the warm-up period, increase the firing rate in 25% (1.0V) increments while
monitoring the gas pressure after every increase. If gas pressure dips below 9.5” W.C. for FM
gas trains and 9.9” for IRI gas trains at any input firing rate percentage, stop and raise the
pressure. Once 100% (5.0V) is reached, adjust the gas pressure for 9.5” (FM) W.C. or 9.9”
W.C. (IRI).
NOTE
If 9.5” W.C. for FM gas trains or 9.9” 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.
7. Once 9.5” W.C. or 9.9” W.C. is set at the 100% (5V) level, change the firing rate to 25%
(2.0V). Insert the combustion analyzer probe into the stack.