PN 9000-280-VE, Rev B
Possible Cause
Corrective Action
Calibration gas solenoid stuck open:
To check if a calibration gas solenoid is stuck open, verify that no
drive signal is present and check for flow on the RCU flow meter.
If flow is indicated when no solenoids are energized, a solenoid
is stuck open. Shut off your calibration gases (one at a time) until
the flow drops to zero. This identifies the defective solenoid valve
(replace the solenoid valve, being sure that the solenoid o-ring
seals are properly positioned).
Calibration Gas Time Inadequate:
If you are having problems running an auto calibration, you may
not have allowed the calibration gases enough time to flow
through the analyzer and stabilize. To correct this problem, select
Inject Cal Gas
from the
Diagnostic
menu.
Turn on each calibration gas and determine how long it takes for
each gas to stabilize on the control unit display. Then add a one
minute buffer to each of these times. Also make sure the cylinder
regulators are set to the correct pressure. See the
Flow Section of
the System Interconnect Drawing
for the system flow and pressure
requirements. This drawing is included with your installation
package.
Select
Cal Gas Duration
from the
Calibration
menu to set
calibration gas times.
AC Power Checks
Possible Cause
Corrective Action
Loss/Inadequate AC Volt-
age to the Analyzer
Measure the AC voltage to the
Sensor
board at terminals
L
and
N
. Ensure that this voltage is sufficient. Check the measure-
ment technique used by the Volt meter (for example, RMS, aver-
age, peak, etc.). Specifications are based on RMS measurements.
Furnace Checks
Possible Cause
Corrective Action
Open Furnace
Disconnect power to the control unit and the analyzer. With Ohm
meter, measure across Terminals
FURN
on the connector. At
room temperature, the resistance should be:
115 VAC furnace coil: 49 ohms
230 VAC furnace coil: 177 ohms
If the furnace resistance is open, replace the furnace.
Loss of AC Power
to the Furnace
Verify the correct line voltage at
L
and
N
of the
Sensor
board.
With line voltage present, check the voltage at terminals
FURN
on the
Sensor
board. If voltage is present and the system is
not heating, remove power and check the furnace resistance. If
no voltage is present at terminals
FURN
on the
Sensor
board,
replace the
Sensor
board.
3-8 | Thermox
®
WDG-V UOP ATEX-IECEx Analyzer
