IBC Technologies SL 80-399 - Page 45

3-3
STARTUP AND COMMISSIONING
SL 80-399 MODULATING GAS BOILER
4. Withacombustionanalyzerprobeintheuegastestport,turntheGas:Air
Ratio Adjustment screw (see Figure 28, “B”) to achieve 25% excess air
(corresponding CO2 values are 9.4% for natural gas and 10.7% for propane).
Thisscrewoffersveryneadjustment,andmayrequireseveralturns.
NOTE:Thisscrewhassignicantbacklash.Whenchangingdirectionofturn,
it may take up to a full turn before any change is indicated on the analyzer
reading.Clockthegasmetertoconrmfullmaximumratingplateinput.
5. Toconrmoradjusttheminimumrelevelsettings,Re-denetheloadas
“ManualControl”.UseHeatOutputin“CongureLoadx”tocontroltheoutput
as needed.
6. Attheminimumringrate,adjustthezero-offsetscrew(see Figure 28, “A”)
to obtain 25% excess air. It may be necessary to reduce the output in stages
if this adjustment has been tampered with.
7. Turnboileroffbyremovingthecallforheat(usetheHeatLoadConguration
screen to turn load to off if no other ready means available), then remove the
manometer connections, and turn the centre-screw in the manifold pressure
test port 1 full turn clockwise. Ensure fully closed, but not over-tightened.
Zero-offset adjustment screw
Gas:Air ratio adjustment screw
Insertion of ue gas analyzer probeRemoval of ue gas test port plug
Flue gas test port plug
DANGER
Making adjustments to
the IBC gas valve without
a properly calibrated gas
combustion analyzer and by
persons who are not trained
and experienced in its use
is forbidden. Failure to use
an analyzer can result in an
immediate hazard.
Figure 32: Gas Valve and Pressure Reference System