3 MAINTENANCE OF INSTRUMENTS. R e p a i r or replace defective parts as required
a f t e r the yearly inspection; for example:
(a) Replace distorted Bourdon tube assemblies which have been subjected
t o overpressure.
( b ) Replace temperature bulbs which are swollen as a result of excessive
(c) Replace all gauge movement linkages, pins, and bushings which have
lost motion caused by wear.
( d ) Replace or repair broken adjustment assemblies.
Mercury is poisonous.
A v o i d breathing mercury vapor. Avoid
r e p e a t e d skin contacts
which may cause serious skin irritations.
K e e p mercury in clean
dark containers with plastic bottle caps.
Mercury dissolves many
( e ) Clean dirty mercury by straining through chamois cloth.
(f) Repair all leaks in piping or meter.
(9) Repair or replace defective floats.
( h ) Replace defective gaskets.
( i ) Rod out all plugged or partly plugged pipeline connections.
( j ) Clean out the meter connecting piping by blowing down with the
( k ) Lubricate only those parts which the manufacturers' instructions
s t a t e r e q u i r e l u b r i c a t i o n . Use recommended lubricants.
( 1 ) Replace all corroded, b e n t , or otherwise defective parts.
( m ) Check calibration of all instruments and gauges.
4 TEST AND CALIBRATION OF INSTRUMENTS.
4 . 1 Thermometer Calibration. Calibrate thermometers weekly by comparing
readings with those of a glass-stemmed, s t a n d a r d i z e d laboratory thermometer.
Locate the bulb of the instrument and the laboratory thermometer in a heated
b a t h which is agitated to ensure uniform heating within range of
thermometers. T a k e readings as the temperature rises. Correct the instrument
under test by means of the adjusting screw or by displacing the scale as
r e q u i r e d . A f t e r making the corrections, repeat the calibration. Be careful
not to subject the instrument to temperatures above its designed maximum. See
p a r a g r a p h 4.4 for calibration of electronic temperature measurement