Calibration/Aspirator Setup Checks - Ametek Thermox Series 2000 WDG-IV User Manual

Calibration/Aspirator Setup Checks

Calibration Gas Check
To check calibration gas
values:
select the Cal Gas Value
menu option from the Cali-
brate key on the control unit
and check that the calibra-
tion gas values entered
match the analyzed concen-
tration of the cylinders.
Calibration Line Check
The best calibration gas to
use for this check is an O
zero calibration gas.
Aspirator Not Turned OFF
during Calibration
Remote Calibration Unit
(RCU) Problem
Plumbing Leak
Solenoid Not
Energizing
6-8 | Thermox Series 2000 WDG-IV / IVC / IVCM
Check that the correct calibration gas values have been en-

tered into the control unit.
Check that the calibration gas cylinders are turned on and are

not empty.
Check for the proper flow rate and proper delivery pressure

of calibration gases when the remote calibration unit has
been activated (see the Inject Cal Gas menu option from the
Calibrate key chapter for help).
Ensure that your calibration line is not contaminated with such
things as pipe dope, cutting fluid, oil, or solvents. All these
contaminants produce hydrocarbon vapors that interfere with
the proper calibration of your analyzer, resulting in lower than
2
expected oxygen readings. To test for contaminated lines, you
must temporarily bypass your current calibration line with a clean
calibration line (directly from cylinder to the sensor calibration
inlet port, using a flow meter to set the proper flow) and compare
the response with that from the possibly contaminated line.
WDG-IV only
Verify that the aspirator air is turned off during calibration (man-

ual or through the RCU). If the problem is with the RCU, refer to
NOTE
the next section, "Remote Calibration Unit Problem."
The RCU contains one normally open solenoid-the aspirator air
solenoid. All other solenoids are normally closed. Problems with
the RCU are usually as follows:
To check for plumbing leaks, disconnect power from the RCU
and pressurize the inlets. Apply a leak detecting liquid along
the base of the solenoids and any plumbing fittings. Repair any
leaks found.
The solenoid drive signal is a 12 VDc signal. This is used to
close the aspirator solenoid and open the appropriate calibra-
tion gas solenoid. To test a solenoid valve, select Inject Cal Gas
from the Calibrate key menu to energize that solenoid. Verify
that the solenoid drive signal is present. The aspirator air sole-
noid is closed when the drive signal is applied. Other solenoids
are open when the drive signal is applied (cal gas flowing). With
the drive signal present, verify the proper flow. If no signal is
present, check the interconnecting wiring between the control
unit and the Rcu.
If wiring is correct, replace the Auto Cal Card. If the solenoid
drive signal is present, it indicates a problem with one of the
solenoid valves. Replace the solenoid valve, being sure that the
solenoid O-ring seals are properly positioned.