Bacharach PCA3 Addendum

This addendum applies to the PCA
0024-9472 Rev 1 (Domestic) and 0024-9473 Rev 2 (Siegert). It covers the
new Manual Zero feature. If you have any questions, contact Bacharach
Customer Service.
The new manual zero feature provides a choice of zero mode during startup:
the existing Auto Zero or the new Manual Zero.
Manual Zero: When the CO channel is set to manual zero, the analyzer
does not zero the CO sensor to ambient conditions during start up. In this
mode, the "fresh air zero" established during manual mode setup is stored
in memory and used during the calculation of CO.

Auto Zero:

zeroed to the ambient CO level during start up. Important: When using
this mode, the analyzer must be turned ON in fresh air; otherwise,
incorrect CO readings will occur.
Auto Zero (among other things) determines the zero reading of the CO
channel in fresh air and provides an offset for the CO measurements. Manual
zero is used to detect CO that may be present during start-up.
auto/manual zeroing option allows the operator to select the start-up mode. It
is selectable from the CO Zero Setting of the Setup Menu.
1. From the SETUP MENU, use the ▲▼ buttons to highlight CO Zero
Setting, and then press ENT to display the CO ZERO SETTING MENU.
2. Use the ▲▼ buttons to highlight the desired option (Manual or Auto
Zero), and press ENT to save the selection and re-display the SETUP
MENU.
Both methods take the user through a 60-second count down to establish a
new zero. The manual mode establishes a fresh air zero and stores it for use
during instrument startup.
A
DDENDUM
When the CO channel is set to auto zero, the CO sensor is
PCA
®
3 Operation and Maintenance Manuals
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®
3 Manual Addendum
September 2011
0024-9483 Rev 0
The