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 Section 2.
OPERATION AND MAINTENANCE OF INSTRUMENTS
1 INSTRUMENT USAGE. The proper use and care of instruments are important
f a c t o r s i n t h e i r r e l i a b i l i t y a n d l i f e s p a n . P e r f o r m the following procedures
f o r the care of instruments.
( a ) Report any malfunction in the operation of any instrument or gauge.
( b ) Wind hand-wound chart drives of recording instruments with 24-hour
movements at the same time each day; wind those with 7--day movements at the
same time each week.
( c ) Protect gauges from violent fluctuations by throttling the gauge
n e e d l e valve or by installing snubbers.
( d ) Clean gauge glasses as required for ease of reading.
On steam meter installations, make sure the connecting pipes
b e t w e e n the meter and the primary element are filled with
c o n d e n s a t e before placing the meter in service.
(e) Protect flowmeters that operate on the principle of differential
p r e s s u r e by not placing them in service unless there is pressure and flow in
t h e metered pipeline. Remove the meter from service before shutting down the
p i p e l i n e . T h i s type of flowmeter is placed in service as follows:
( 1 ) Open equalizing valve.
( 2 ) Open low-pressure shutoff valve slowly.
(3) Close equalizing valve.
( 4 ) Open high-pressure shutoff valve slowly.
( f ) To take a differential pressure flowmeter out of service, or when
c h e c k i n g the zero adjustment, close high- and low-pressure shutoff valves and
o p e n equalizing valve. C o n s u l t manufacturer's instructions for recommended
procedures.
2 PREVENTIVE MAINTENANCE OF INSTRUMENTS. O n l y authorized and trained
p e r s o n n e l should repair, calibrate, or adjust instruments. The following
paragraphs present maintenance inspection routines adequate for average
installations.
2 . 1 Daily Inspection of Instruments. I n s p e c t all accessible instruments and
g a u g e s for defects such as leaks, cracked or broken glass, bent pointers,
l o o s e connections, changed terminals, b r o k e n wiring, or any other obvious
f a u l t s . Report any defects immediately.
6-21
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