Table 11 Wash Troubleshooting - Vaisala PR-23 Series User Manual

PR-23 Series User Guide
Problem
Message TEMP MEASUREMENT
FAULT
Concentration drift during Normal
operation
Table 11 Wash troubleshooting
Problem
Message EXTERNAL HOLD
Messages PRECONDITIONING,
WASH, RECOVERING
Message PRISM WASH WARNING
Message PRISM WASH FAILURE
Message EXTERNAL WASH STOP
Message LOW TEMP WASH STOP
Message NO SAMPLE / WASH
STOP
96
Cause
Indicates faulty temperature
element.
For drift upward, suspect prism coating, see
Otherwise check calibration, see
(page 72), and sensor verification, see
Cause
The concentration measurement is on HOLD due to an external switch
closure. For explanation, see
PRECONDITIONING: An optional
preconditioning relay is closed.
WASH: The internal wash relay is
closed.
RECOVERING: The concentration
measurement is on HOLD during a
preset time.
No dip of n value during prism wash. The accepted size of the dip is set
D
as the WASH CHECK function, see
See also Testing prism wash (page
No dip of n value during any prism wash during wash tolerance time.
D
The wash tolerance time is set in wash parameters, see
wash parameters (page 82). See also
Tells that wash action is prevented because an EXTERNAL WASH STOP
switch is closed, see Configuring input switches (page
• NO SAMPLE indicates an empty pipe.
Tells that wash action is prevented
because of LOW TEMP: low
process temperature indicates
empty pipe.
Tells that wash action is prevented because of NO SAMPLE: the process
pipe is empty and the prism is clean.
Corrective action
Replace the temperature element.
A difference to
some other
process
temperature
measurement is
not a fault.
PR‑23 measures
the true
temperature of
the prism
surface.
Prism coating (page
Calibrating concentration measurement
Sensor verification (page
Corrective action
Configuring input switches (page
See Configuring prism wash
(page 77).
Configuring prism wash (page
Configuring prism wash (page
51).
Testing prism wash (page
To set the limit, see
prism wash (page
IM-EN-PR23-E
37).
242).
68).
77).
77).
Setting prism
51).
68).
Configuring
77).