Cashco DA4 - Manual

INSTALLATION, OPERATION & MAINTENANCE MANUAL (IOM) IOM-DA4
11-13
I. DESCRIPTION AND SCOPE
Model DA4 is a pressure reducing regulator used to control downstream (outlet or P2) 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. Refer to Technical Bulletin DA4-TB
for design conditions and selection recommendations. (NOTE: This product was formerly identifi ed as a Model
D4; a Model DA4 and D4 are one and the same product.)
This manual does not include instructions related to the various methods of pressure loading a Model DA4
main valve.
MODEL DA4
(Formerly DA3/4)
DIRECT-ACTING, PRESSURE LOADED
PRESSURE REDUCING REGULATOR
(Model DA3 was identical to DA4 except that the DA3 did not include a lower return spring.)
II. REFERENCES
Refer to Technical Bulletin DA4-TB for tech ni cal
specifi cations for this reg u la tor.
ABBREVIATIONS
CW – Clockwise
CCW – Counter Clockwise
ITA – Inner Trim Assembly
III. INSTALLATION
SECTION III
SECTION II
SECTION I
1. 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 con-
nection to bleed-off trapped gas/air under the
diaphragm.
2. Provide space below, above, and around reg u la-
tor for removal of parts during maintenance.
3. 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 seal.
4. Downstream 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/
External Sensing.
b. Reference DA4-TB, Table DAG-11 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
1/4" (DN8) NPT tap (Port 5 – See Fig. 6) on
the side of the body di a phragm fl ange to a
pressure tap down stream of the regulator.
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.