Readings Menu - Seitron CHEMIST 400 Use And Maintenance Manual

4.15

Readings Menu

This menu is used to access the following readings:
Carbon black:
It is possible to enter the data concerning one to three CARBON BLACK measurements taken by means of an
optional device (BACHARACH PUMP); see the relevant instructions.
The method consists in taking a certain quantity of combustion gas from the middle of the flue behind the
surfaces of the exchangers at the end of the boiler, and make it pass through a special filter paper. The soot
stain obtained is compared with the surfaces blackened in a different way according to a comparison scale; it is
thus determined the "soot number", which will be entered in the instrument by hand.
These measurements can be either stored in memory together with the combustion analysis data or printed on
a ticket.
Ambient CO, NO:
This type of analysis lets the user measure the CO and NO values present in the environment, with the scope of
checking the personal safety conditions of a specific working environment. The instrument leaves our factory
with the following preset threshold values:
COmax: 35 ppm Recommended exposure limit (REL) stipulated by the National Institute for Occupational
Safety and Health (NIOSH), equivalent to 40 mg/m
Average (TWA).
NOmax: 25 ppm Recommended exposure limit (REL) stipulated by the National Institute for Occupational
Safety and Health (NIOSH), equivalent to 30 mg/m
Average (TWA).
It is compulsory to perform the autozero in the clean air, so that the ambient CO and NO
measurement is correct. It is advisable to turn on the instrument and wait for the autozero
completion outside the area where the test is being performed.
The result of the test can be either associated to the combustion analysis and consequently stored in memory
or immediately printed through the 'Print' menu.
Pressure:
It is possible, through the use of the external flexible pipe made in RAUCLAIR (supplied), to measure a
pressure value within the range stated in the technical features (connect the pipe to P+ input). During the
pressure measurement the 'HOLD' function is made available, which allows to 'freeze' the value shown on the
display, by pressing 'HOLD' key.
Tightness test:
Chemist 400 can perform the tightness test on heating plants which use combustible gases according to the
standards UNI 7129 and UNI 11137: 2012, respectively applicable to new or renewed pipings and to existing
pipings. The result of this tightness test, whose steps are described in the following, can be printed, once
acquired, by starting the ' print menu ' in any of the screens of the ' Tightness Test ' menu.
New piping: UNI 7129 STANDARD
The standard UNI 7129 can be adopted for testing new piping systems or reconditioned ones. This test requires
to charge the piping up to a pressure of at least 100 mbar, then wait for a stabilization time of at least 15
minutes required for nulling the thermal effects caused by the test gas compression and finally check for the
tightness of the piping by analysing the way the pressure eventually decays against time. This check expects for
no difference between two pressure readings performed in 15 minutes and with a manometer having a
minimum resolution of 10 Pa.
Chemist 400 allows the user to customize the stabilization phase through the following parameter:
WAIT TIME: it is the stabilization time and can be set by the user from 15 to 99 minutes. Please note that UNI
7129 standard requires a stabilization time of at least 15 minutes, anyway there is the possibility to skip
stabilization by pressing '
Once the stabilization parameter has been set the user can proceed with the tightness test. Selecting the item
'Start Test', the test pressure required by the standard is shown, then a screen with actual pressure applied to
the instrument inputs is displayed. After having zeroed the instrument and, subsequently, having charged the
piping with at least 100 mbar, the tightness test can be started through the option 'TEST', which actually starts
the stabilization phase. In the stabilization screen the following values are displayed:
K900000000SE 022628A0 071013
' button.
3
and calculated as an 8-hour Time-Weighted
3
and calculated as an 8-hour Time-Weighted
1
2
3
4
5
6
7
8
43