Appendix E: Technical Notes
Note 1:
When performing a pressure or draft test during a combustion test, the
pump can be turned on to provide a continuous sample to the sensors. This
enables pressure adjustments to be made and the affect to the combustion
process can be seen by returning to combustion analyzer mode. Use the FUNC
Key to activate manometer mode. Press and hold the Up Arrow Key until the
pump reactivates. Perform a pressure test and then use the FUNC key to acti-
vate combustion analyzer mode. Repeat this process until pressure adjustments
are complete.
Note 2:
Several factors affect combustion efficiency. Dirty or clogged air filters
reduce the amount of air available for combustion therefore reducing efficiency.
Obstructions in the flue block exhaust gases and alter the air mixture in the
combustion chamber which reduces efficiency. Air leaks in the combustion
chamber also alter the mixture causing decreased efficiency.
Note 3:
The primary way to affect change in combustion efficiency when work-
ing with modern gas fired equipment is through gas manifold pressure adjust-
ment. Confirm manifold pressures are within maufacturers specifications prior
to performing a combustion test. Once manifold pressures are within limits a
combustion test can be performed to provide information regarding any adjust-
ments that may be needed.
Note 4:
Gross efficiency calculation takes into account wet losses (latent heat)
and is the unit of measure used in the USA. Net efficiency only takes into
account dry losses (latent heat is not figured in) and is used in Europe.
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