Model 422 & Model 422CC Instruction Manual
D01187869
Revision A, December 2015
42
11
Maintenance and Basic Servicing
Regular maintenance and basic servicing procedures are described in this section. If
more extensive maintenance or service of the instrument is required, please contact
Fann Instrument Company.
11.1 Pressure Vessel and Hydraulic System Maintenance
The metal o-ring, the pressure vessel o-ring seat, and the bottom of the seal shaft
are the keys to reliable pressure sealing. If these components are free from debris
and scratches/dents, reliable sealing will be easily achieved.
1.
Inspect the pressure vessel’s o-ring and the seat below it after each test and
wipe it free of cement particles and other debris. Do not use sharp objects,
such as screwdrivers, when removing the o-ring as it will likely bend or
scratch the o-ring, ruining it. Should the seat below the o-ring or the seal
shaft become pitted or scratched from cement particles that have migrated
into the seal, lapping of the seat and seal shaft may be required.
2.
The cylinder plug threads have been coated with a friction reducing PTFE
coating by the factory to help prevent thread seizing and galling. However,
it is still recommended to apply a molybdenum disulfide anti-seize
compound to the threads periodically.
If the transfer of the oil from the pressure vessel to the reservoir is
slow, the filter should be cleaned or replaced.
3.
The high-pressure filter is located just to the right of the pressure vessel.
This filter protects the air operated valves and capillary tubes from cement
particle damage and/or blockage. It also prevents cement particles from
being carried into the oil reservoir. This filter must be disassembled and the
filter element cleaned or replaced periodically.
4.
The mineral oil in the reservoir should be drained and replaced when it
becomes dirty. The low-pressure oil filter element should also be replaced
periodically. The oil reservoir is equipped with drain valve on the bottom
and a filling plug at the top. To thoroughly clean the reservoir, the entire
unit may be taken out of the instrument and the bottom removed. Mineral
oil may be conveniently added by pouring oil into the pressure cylinder and
