Manual instruction MM850482 ed.04
11
N
OTE
:
T
O OBTAIN AN ACCURATE MEASURE IT IS RECOMMENDED TO WAIT
3-5
MINUTES
.
If an excessive (>150% of F.S.) gas concentration is applied to toxic gas sensor, then a ±2% drift and a long
resuming time can be present. In that case it is recommended to wait for a measured value lower than 20
ppm, by sucking fresh air before switching the analyzer off.
Four acoustic and visual alarm levels can be set on four programmable parameters.
3.2 Auxiliary
Measurements
3.2.1 Temperature
Measurements
The instrument is equipped with two temperature inputs to measure exhaust gas and the burner air input
temperatures (combustion gas).
♦
A thermocouple type K (nickel-nickel chromium) is included in the tip of the gas sampling probe to
measure the
flue gas/exhaust gas temperature
. This thermocouple is suitable for permanent
measurements at temperatures up to 800°C and for short-term measurements up to 1000°C.
Temperature measurement and gas sampling from the flue gas pathway are thus always performed at the
same site. The probe is connected to the apparatus with compensated cable and connector. An internal
Pt100 resistance thermometer is used for cold junction compensation.
♦
A remote Pt100 sensor can be supplied on request with a 2-meter cable to measure the
air inlet
temperature
in forced air boiler. This option is very important for an accurate efficiency calculation.
3.2.2
Pressure and Draft
The analyzer is equipped with a temperature compensated pressure sensor to measure the chimney draft or
pressure. The pressure/draft sensor is based on the principle of the extension metric measuring bridge. The
pressure range is -100 to 100mbar. The sensor is factory calibrated and does not require manual adjustment.
The zero drift, caused by ambient air temperature variation, is automatically cancelled at each instrument
start-up. In addition, for more accurate readings the operator can reset, using the pertinent key, the zero if
required. Leave open the “
∆
P” connector during this phase.
N
OTE
:
W
E SUGGEST EXECUTING THE AUTOZERO PROCEDURE FOR MORE ACCURACY BEFORE PERFORMING THE
MEASUREMENT
.
CAUTION
I
F A SINGLE TUBE GAS SAMPLING PROBE IS USED FOR
P
RESSURE
/
DRAFT MEASUREMENTS
,
BE SURE THAT IT IS CLEAN AND
DRIED BEFORE CONNECTING TO THE PRESSURE INPUT
.
CAUTION
A
+300
H
P
A
(
OR
–300
H
P
A
)
OVER
-
PRESSURE CAN PERMANENTLY DAMAGE THE PRESSURE SENSOR
.
