103448-02 - 6/13
89
Warning
The throttle adjustments shown in Table 28 are approximate. The final throttle setting must be found using
a combustion analyzer. Leaving the boiler in operation with a CO level in excess of the value shown in
Table 27 could result in injury or death from carbon monoxide poisoning.
nOTiCE
if the throttle is very far out of adjustment on the “rich” (counter-clockwise) side, the boiler burner may be
running at 0% Excess Air or even with air deficiency.
At 0% Excess Air the CO
2
readings will be either 11.9% CO
2
for Natural Gas or 13.8% CO
2
for LP gas (O
2
will
be 0%) and CO level will be extremely high (well over 1000
PPM).
If the burner operates with air deficiency, the following phenomena may be observed:
% CO
2
will actually drop
(% O
2
will increase) as the throttle is turned counterclockwise
% CO
2
will actually increase
(% O
2
will drop) as the throttle is turned clockwise
If the boiler appears to operate with air deficiency, turn the throttle
clockwise to increase the amount of
Excess air to the burner.
as the throttle is turned clockwise, the CO
2
level will rise
, eventually peaking @ 11.8% or 13.8%, depending
of the type of gas being used, before falling (conversely, O
2
level will drop
to 0% before rising). After this
happens, continue turning the throttle clockwise, until CO
2
level drops (or O
2
level increases) to the values
shown in Table 26 or Table 27.
Warning
The pressure regulator (offset screw) has been factory set using precision instruments and must never
be adjusted in the field unnecessarily. The gas valve outlet pressure is the same for both natural gas and
propane. Make sure that all adjustments are made with the throttle, not the pressure regulator. attempting
to adjust the pressure regulator unnecessarily, may cause property damage, personal injury or loss of life.
iX. System Start-up
(continued)
