Cashco DA6 - Manual

INSTALLATION, OPERATION & MAINTENANCE MANUAL (IOM) IOM-DA6
11-13
I. DESCRIPTION AND SCOPE
The Model DA6 is a pressure loaded back pressure regulator used to control upstream (inlet or P1) pressure. Sizes
are 1/2" (DN15), 3/4" (DN20), 1" (DN25), 1 1/4" (DN32), 1 1/2" (DN40), 2" (DN50), 3" (DN80) and 4" (DN100). With
proper trim uti li za tion, the unit is suitable for liquid, gaseous, or steam service. Typically installed in a more com-
mon “reverse” fl ow direction arrangement that is balanced (to outlet). Refer to Technical Bulletin DA6-TB for design
conditions and selection rec om men da tions. (NOTE: This product was formerly iden ti fi ed as a Model D6; a Model
DA6 and D6 are one and the same product.)
MODEL DA6
DA6 - DIRECT-ACTING, PRESSURE LOADED
BACK PRESSURE REGULATOR
SECTION I
II. REFERENCES
Refer to Technical Bulletin DA6-TB and DAG-TB for
tech ni cal specifi cations of a Model DA6 regulator.
ABBREVIATIONS
CCW – Counter Clockwise
CW – Clockwise
ITA – Inner Trim Assembly
III. INSTALLATION
1. Install per direction of fl ow arrow indicated on body,
or "IN" and "OUT" markings.
2. Regulator may be rotated around pipe axis 360
degrees. For ease of maintenance, the rec om -
mend ed position is with the cover dome (25)
up wards. In liquid service it is recommended that
the cover dome (25) be oriented down wards, and
that a cus tom er supplied and installed vent valve
be pro vid ed at the external sensing connection
to bleed-off trapped gas/air under the diaphragm
during initial startup.
3. Provide space below, above, and around reg u la tor
for removal of parts during maintenance.
4. Install block valves and pressure gauges to pro-
vide means for adjustment, operation, bypass,
or removal of the regulator. A pipeline strainer
is recommended before inlet to remove typical
pipe line debris from entering valve and damaging
internal “soft goods”, primarily the dynamic side
seal and V-TFE seat when applied.
5. Upstream Sensing Installation Considerations
– Internal or External Sensing:
a. The regulator may be installed with internal or
external sensing. Unless otherwise spec i fi ed,
the regulator is supplied by factory with internal
sensing. The regulator may be con vert ed in
the fi eld to external sensing. (See Section VII
Maintenance, Part H – Converting Internal/Ex-
ternal Sensing.)
b. Reference DAG-TB, Table DAG-12 for rec-
om men da tions for applying external pressure
sensing.
c. For internal sensing, no external line is re-
quired. For external sensing, use an external
control line. The line is connected from the
port 1/4" (DN8) NPT tap (Port 5 – See Fig. 5)
on the side of the body di a phragm fl ange to a
pressure tap upstream of the regulator. Use
1/4" (6.4 mm) or 3/8" (9.5 mm) outer di am e ter
tubing or 3/8" (DN10) pipe having an inner
di am e ter equivalent to schedule 40 pipe.
d. For condensable vapors (i.e. steam) slope the
external sensing line downward 2 to 5 de grees
to inlet piping to prevent water pock ets, which
allows the diaphragm chamber to al ways be
self draining. The external sensing line may
be sloped upward for gas or liquid service; i.e.
non-condensibles.
SECTION III
SECTION II
CAUTION
Installation of adequate overpressure pro tec tion
is recommended to pro tect the reg u la tor from
over pres sure and all down stream equip ment from
dam age in the event of regulator failure.