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.

The primary way to affect change in combustion efficiency when working with modern gas fired equipment is through gas manifold pressure adjustment.

Confirm manifold pressures are within manufacturers specifications prior to performing a combustion test. Once manifold pressures are within limits a combustion test can be performed to provide information regarding any
adjustments that may be needed.

10,000ppm is equal to 1%.

The formula to convert percent to ppm is: ppm = %gas X 10,000. The formula to convert ppm to percent is: % = ppm / 10,000.

The 709, 712, and 714 incorporate a differential manometer.

Pressure applied to the (-) port is subtracted from the pressure applied to the (+) port. Examples of pressures being measured:
(+) port = 10"H2O, (-) port = Not Connected, Displayed reading =10"H2O
(+) port = 10"H2O, (-) port = 5"H2O, Displayed reading = 5"H2O
(+) port = Not Connected, (-) port = 10"H2O, Displayed reading = -10"H2O

Sensor Calibration

The sensors in your analyzer will need to be replaced periodically and calibration is recommended once every year. Electrochemical sensors by nature are always active. Therefore the time the analyzer is off and not being used must be taken into account when determining sensor life. The sensors in your analyzer are warranted for two years. This warranty does not cover sensors damaged through misuse of the analyzer.