YOKOGAWA MC43 - Maintenance; Basic Troubleshooting; Component Identification

<5. Maintenance>
5-1
IM 02M04B01-01EN
5. Maintenance
5.1 Basic Troubleshooting
DIFFICULTY:Noreading(orverylowreading)at
output gauge.
F0501.ai
1
2
Output gauge
4
1. Check that 140 kPa (1.4 kgf/cm
2
) is supplied to
controller.
2. Check for measurement reading.
3. Clean restrictor. (refer to section 5.3).
4. Disconnect output line and plug controller
output with nger.
5. Adjust set point knob (or remote set point, if
present) so that set point index goes above and
below measurement pointer. If output gauge
indicates normal control action, there is a leak
in output line or control valve.
6. If output gauge still indicates no control action,
a. Check controller for damage or leaks.
b. Replace amplier (refer to section 5.4).
c. Check control unit alignment (refer to section
5.11 and 5.12).
DIFFICULTY:Maximumpressureatalltimesat
output gauge.
1. Check for mechanical damage resulting in
nozzle always being covered by apper.
2. Check for misalignment of amplier gasket,
resulting in plugging.
3. Replace pneumatic amplier (refer to section
5.4).
4. Clean nozzle (refer to section 5.3).
5. Check control unit alignment (refer to section
5.11 and 5.12).
5.2 IdenticationofMajor
Components in Controller
(1) Model MC43-N-N
F0502.ai
Measurement
pointer
Set point index
Set point and
measurement dial
Output gauge
Measurement
element
(pressure type
illustrated)
Reset
assembly
(optional)
Derivative
assembly
(optional)
Control unit Set point knob Controller without
automatic-manual
transfer system
Pneumatic
amplifier
(2) Model MC43-C-P
F0503.ai
Remote set point element
(optional)
Pneumatic amplifierAuto-man transfer system
(optional)
Shutoff for air to automatic
control section
(controller with automatic-manual
transfer system).