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Appendix B - (continued)
Figure B.1: Gas Valve Detail (High Altitude Only)
4. After 5 minutes of operation check CO
2
and CO
(Air-Free) and ensure it is within the limits outlined
in Table B.3. Air-Free Carbon Monoxide in Flue Gas
must be less than 200 ppm during all operation. If
CO(Air-Free) and CO
2
is within these limits, move
to Step 6 and check fan speed at high fire operation
only.
5. If CO
2
is outside the range outlined in Table B.3,
adjust throttle screw such that the CO
2
falls in this
range while boiler is locked manually in high fire.
Turning throttle screw counter-clockwise increases
the CO
2
, while clockwise rotation leans the mixture,
reducing the CO
2
. Once CO
2
is within the limits in
Table B.3, check CO (Air-Free) again to ensure it is
below 200 ppm. If CO (Air-Free) is above 200 ppm
turn throttle screw clockwise in 1/8 turn increments
until CO (Air-Free) is below 200 ppm, while
ensuring CO
2
remains in the range specified in Table
B.3. If CO
(Air-Free) is still above 200 ppm, reduce
fan speed in 100 rpm increments until CO (Air-Free)
is less than 200 ppm.
6. Start boiler five times at the above settings to ensure
boiler lights off without delay and without noise.
Check CO
2
and CO (Air-Free) to ensure that the
CO
2
is within the range specified in Table B.3 and
CO (Air-Free) is below 200 ppm. Be sure to replace
the screw cap in the vent adapter when combustion
testing is complete.
7. Lock boiler in low fire. Ensure CO
2
and CO
are within limits. If CO
2
is not, adjust offset on
gas valve at minimum input rate to bring into
specification.
8. Verify that the gas inlet pressure is between the
following limits with all gas appliances (including
the converted boiler) both on and off:
• Natural Gas: 4.0 - 14.0 inches w.c.
• LP Gas: 8.0 - 14.0 inches w.c.
If inlet pressure is not within limits, adjust before
performing high altitude setup procedure.
Offset Regulator
- Do Not Adjust
Tube to Air
Proving Switch
Gas Outlet
Throttle Screw
Outlet Tap
Gas Inlet
Inlet Tap
