18
Routine Maintenance
Responsibility
To preserve the life and efficient operation of the equipment it is important that the
equipment is properly maintained. Regular maintenance of the equipment is the
responsibility of the end user and must be performed by qualified personnel who
understand the operation of the equipment.
General
The equipment should be disconnected from the electrical supply when not in use.
After use the feed bottles, reactor vessel, sump tray and pipework should be washed
through with water to remove chemical residues and then drained.
RCD Test
Test the RCD by pressing the TEST button at least once a month. If the RCD button
does not trip when the Test button is pressed then the equipment must not be used
and should be checked by a competent electrician.
Temperature sensor calibration
The temperature sensors are calibrated before delivery and should not require re-
calibration. However should calibration become necessary follow the below
procedure. This should only be done once the unit has fully warmed up.
The temperature conditioning circuit (which provides the reading from the
conductivity probe supplied with the CEXC service unit) is located on a printed circuit
board inside the plinth on the right-hand side. This circuit is calibrated before
despatch and should not require re-calibration. However, should re-calibration
become necessary the appropriate calibration potentiometers can be located using
the diagram given in the CEXC manual (Routine Maintenance).
Connect CEXC service unit to a PC and start up the Armfield software. Open mimic
diagram screen where T1, T2 and T3 windows are displayed.
If a thermocouple calibrator is available:
Connect Thermocouple calibrator simulator to T1 input socket. Set to 25ºC and
adjust VR1 (T1 ZERO) and VR2 (T1 SPAN) on the PCB to give 25ºC displayed on
PC. Check accuracy at 15º and 40ºC.
Repeat the same procedure for T2 by adjusting VR3 (T2 ZERO) and VR4 (T2 SPAN)
on the PCB to give 25ºC displayed on PC, and VR5 (T3 ZERO) and VR6 (T3 SPAN)
for T3.
If a thermocouple calibrator is not available:
Temperature sensor T1, T2 and T3 should be dipped into crushed ice, and then
adjust the ZEROS to give 0ºC, then sensors should be dipped into boiling water and
then adjust the SPANS to 100ºC.
Calibration of the conductivity sensor
The Low and High conductivity conditioning circuits (which provide the reading from
the conductivity probe supplied with the CEXC service unit) are located on the
printed circuit board shown above inside plinth. These circuits are calibrated before
