Cashco 3381 - Manual

MODELS 3381 AND 4381
PRESSURE RE DUC ING REGULATORS
SECTION I
Models 3381 and 4381 are pressure reducing regulators used to control downstream (outlet or P
2
) pressure.
Sizes are 1/4" and 3/8" (DN8 and DN10) for the 3381. Sizes for the 4381 are 1/4", 3/8", and 1/2" (DN8, DN10,
and DN15). The 3381 is a bronze bodied unit; the 4381 incorporates a stainless steel body. With proper trim
utili za tion, both units are suitable for liquid, gaseous and steam service (the 4381 can also be used with vari-
ous chemi cals). Refer to Tech ni cal Bul le tins 3381-TB and 4381-TB for specifi c design conditions and selection
rec om men da tions.
The instructions in this manual will apply to both models, unless otherwise stated.
I. DESCRIPTION AND SCOPE
II. INSTALLATION
SECTION II
INSTALLATION, OPERATION & MAINTENANCE MANUAL (IOM) IOM-3381/4381
12-13
1. An inlet block valve should always be installed.
2. If service application is continuous such that
shut down is not readily accomplished, it is rec-
ommended that an inlet block valve, outlet block
valve, and a manual bypass valve be installed.
3. Pipe unions should be installed to allow removal
from piping.
4. An outlet pressure gauge should be located ap-
proxi mately ten pipe diameters downstream, and
within sight.
5. All installations should include a downstream re lief
de vice if the inlet pressure could exceed the pres-
sure rating of any downstream equip ment or the
maximum outlet pressure rating of the unit.
6. Clean the pip ing of all foreign material including
chips, welding scale, oil, grease and dirt before
installing the reg u la tor. Strainers are rec om -
mend ed.
7. In plac ing thread seal ant on pipe ends pri or to
en gage ment, ensure that excess material is re-
moved and not allowed to enter the regulator upon
startup.
8. Flow Direction: Install so the fl ow direction match-
es the arrow cast on the main regulator body.
9. For best performance, install in well drained hori-
zon tal pipe, properly trapped if a steam service
ap pli ca tion.
CAUTION
For welded installations, all internal trim parts, seals and
diaphragm(s) must be removed from reg u la tor body prior
to welding into pipeline. The heat of fusion welding will
dam age non-metallic parts if not re moved. NOTE: This
does not apply to units equipped with extended pipe
nip ples.
CAUTION
Installation of adequate overpressure pro tec tion is recom-
mended to pro tect the reg u la tor from overpressure and
all down stream equip ment from damage in the event of
regulator failure.
CAUTION
Option-1+6 contains single di a phragm con struc tion. In
the event of diaphragm fail ure, the process fl u id will mix
with the load ing fl uid. Please alert your rep re sen ta tive so
an al ter na tive product can be se lect ed.