Rinnai RCB Serie Manuel page 10

3. Use a combustion analyzer to verify CO2 is within the range listed on Table 4 for both maximum and
minimum firing rates (Figure 12). If not, adjust the throttle screw counterclockwise incrementally to
increase CO2 and clockwise to decrease CO2 for maximum firing rate. For minimum firing rate, adjust the
offset screw counterclockwise to decrease CO2 and clockwise to increase CO2 (Figure 13).
IMPORTANT
When making adjustments to the gas valve, it is critical to make a small adjustment first, then wait for the
combustion to settle before making further adjustments. The boiler is pre-set at the factory and only a slight
adjustment should be made to the gas valve for tuning. Make adjustments to the minimum firing rate first,
and then proceed to the maximum firing rate adjustment.
Figure 12
Figure 13
Throttle Screw
Table 4
TYPE OF GAS
NG
PROPANE
4. After measurement, remove the gas analyzer probe and replace the combustion port plug.
WARNING
10
Information in table applies to both Minimum and Maximum adjustments.
CO2 TARGET (%)
9.0
10.0
You must replace the combustion plug in the vent adapter to avoid flue gas leak
into the room. Failure to comply could result in severe personal injury, death, or
substantial property damage.
Manifold
Pressure Port
Manometer
Offset
Screw
Torx Plug
CO2 RANGE (%)
8.5 - 9.5
9.5 - 10.5
Rinnai Commercial Boiler Conversion Manual
Inlet
Pressure Port
CO LIMIT (PPM)
< 175 PPM
< 175 PPM