7. Inspection and Maintenance
To ensure the long service life of the DR20/A-DR20, the following inspection and maintenance
should be performed regularly, at least once a year. It is especially important to perform an
inspection immediately after the initial run of a new line or before or after equipment such as a
heater is out of service for a long period of time.
Wait for the body to cool before attempting to remove the DR20/A-DR20 from the line. Then
remove the DR20/A-DR20 from the piping and secure it in a vise to perform the inspection.
Parts Inspection Procedure
Body, Cover
Screen
Valve and Valve Seat
Valve Stem
Bellows
Gaskets
Check inside for damage, dirt, grease, oil film, rust or scale
Check for clogging, damage or deformation
Check for rust, scale, oil film, wear or damage
Check for wear or damage
Check for cracks, damage or deformation
Check for warping or damage
7.1 Disassembling the Adjustment Section
Loosen the adjustment handle completely
and remove the cover bolts. After removing
the cover, you will see the steel ball, the
spring guide and the coil spring.
Check for seizure or any damaged screw
threads.
7.2 Disassembling the Bellows Section
Remove the bellows from the body, then the
valve stem. Pinch the straight sections of
the snap ring that is holding the spacer
together using a tool such as a needle-nose
pliers and remove the snap ring. Remove
the spacer.
•
Installation, inspection, maintenance, repairs, disassembly, adjustment
and valve opening/closing should be carried out only by trained
maintenance personnel.
•
Before attempting to open the product, close the inlet and outlet isolating
valves and wait until the body has cooled completely. Failure to do so may
result in burns.
•
Be sure to use the proper components and NEVER attempt to modify the
product.
CAUTION
Cover
Cover Bolt
Locknut
Adjustment
Handle
Retaining
Ring
Spring
Guide
Steel Ball
Coil Spring
* Cannot be removed individually as it is incorporated
with the spacer and must be replaced as a set with the spacer.
Bellows
Cover
Gasket
Snap Ring
Valve Stem
Snap Ring*
Slide Bearing*
Spacer
Slide Bearing*
Snap Ring*
Body
̶ 12 ̶
English
