Emerson Rosemount 6888A Quick Start Manual page 25

October 2019
1.3.2 Calibration gas
The transmitter uses two calibration gas concentrations, low gas - 0.4% O
balance N
CAUTION
Calibration reading errors
Failure to use proper gases will result in erroneous readings.
Do not use 100% nitrogen as a low gas (zero gas). Emerson suggests that
gas for the low (zero) be between 0.4% and 2.0% O
Do not use gases with hydrocarbon concentrations of more than 40
parts per million.
CAUTION
Equipment damage
If the ducts will be washed down during outage, verify that 6888A units have
been powered down and removed from the wash areas.
CAUTION
Equipment damage
Damage can result from having a cold unit exposed to the process gases.
Upon completing installation, ensure that the transmitter is turned on
and operating prior to firing up the combustion process.
During outages, if possible, leave all units running to prevent
condensation and premature aging from thermal cycling.
See Figure 1-13
Quick Start Guide
, and high gas - 8% O
2
for the calibration gas connections.
, balance N .
2 2
Quick Start Guide
.
2
,
2
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