IBC VFC 45-225 - Transformer and Temperature Sensors; 4.2.7 Transformer Function; 4.2.8 Temperature Sensors

3-3
STARTUP AND COMMISSIONING
VFC 15-150 - VFC 45-225 MODULATING GAS BOILERS
4. Withacombustionanalyzerprobeintheuegastestport,turntheGas:Air
Ratio Adjustment screw (see Figure 31, “B”) to achieve 28% excess air
(corresponding CO2 values are 9.2% for natural gas and 10.4% 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 31, “A”)
to obtain 28% 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.
Figure 31: Gas Valve and Pressure Reference System
Zero-offset adjustment screw
Gas:Air ratio adjustment screw
Insertion of ue gas analyzer probeRemoval of ue gas test port plug
NOTE
Upon installation of this
boiler, you must use an
indelible marker on the rating
plate to mark an X in the box
associated with the fuel used.