Yokogawa YVP110 - Manual (Page 39)

<6. Maintenance>
6-1
IM 21B04C01-01E
6. Maintenance
6.1 General
The modular structure of the YVP110 increases the
ease of maintenance work. This chapter describes
cleaning and part replacement procedures that
should be done for maintenance of the YVP110.
The YVP110 is a precision instrument; read the
following carefully when carrying out maintenance.
For calibrations, see Chapter 5.
CAUTION
Precautions for ATEX flameproof type and
type nA instruments
• Flameproof type and type nA instrumets
must be, as a rule, removed to a non-
hazardous area for maintenance and be
disassembled and reassembled to the
original state.
• On the flameproof type and type nA
instruments the terminal cover is locked by
an Allen head bolt (shrouding bolt). When
a shrouding bolt is driven clockwise by an
Allen wrench, it is going in and cover lock is
released, and then the cover can be opened.
When a cover is closed it should be locked
by a shrouding bolt without fail. Tighten the
shrouding bolt to a torque of 0.7 N·m.
Shrouding Bolt
F0601.ai
Figure 6.1 Shrouding Bolts
6.2 Periodic Inspections
To maintain problem-free plant operation, periodic
inspections are essential. At each periodic
inspection, be especially careful when ensuring
that:
• No external damage can be seen.
• No leakage from the YVP110 or the piping
around it can be detected.
• No build up in the drain, or dust or oil adhering
to the air supply line has occurred.
6.2.1 Cleaning the Fixed Nozzle
The fixed nozzle of the YVP110 is attached to the
control relay’s surface that engages the YVP110’s
main structure (see Figure 6.2). Detach the
control relay from the main structure of YVP110 by
following the instruction shown in 6.3.1. Thread a
wire with a 0.25-mm diameter through the nozzle to
clean it. After cleaning the nozzle, place the nozzle
and O-ring at the original position and attach the
control relay again.
F0602.ai
Nozzle
O-ring
O-ring
Figure 6.2 Cleaning the Nozzle
CAUTION
All the O-rings used for the sealing of pneumatic
signal circuits are made of silicon rubber. The
sealing capability is degraded if general silicon
grease is applied. When applying grease to a
sealing part, use a type of grease compatible
with silicon rubber, such as fluoride grease and
grease for silicon rubber.