Model 405 nm NO
2
/NO/NO
x
Monitor Manual Rev. D
31
Required calibration
parameters are outside the
adjustable range when
calibrated using a known
calibration gas.
Flow path is contaminated.
Solenoid valve is
contaminated and not
opening & closing properly.
Air pump is not drawing
sufficient flow.
Contact 2B Technologies for
instructions if contamination
is suspected.
Remove solenoid valve, rinse
with methanol, dry with zero
air, and replace.
As a first check, hold your
finger over the air inlet to
determine whether air is
being drawn in. If there is
flow, measure the flow rate
by removing the top cover
and attaching a high
conductance flow meter to
the exit port of the pump. Air
flow should be greater than
1.4 L/min. If flow is lower,
check for leaks. If there are
no leaks, replace air pump.
Instrument always reads
close to zero for NO
2
concentrations.
Solenoid valve cable is not
properly connected to circuit
board.
Internal NO
2
scrubber is
exhausted.
Reattach solenoid valve
cable to circuit board.
Contact 2B Technologies
about replacement of the
internal NO
2
scrubber.
