Emerson 75A Instruction Manual
Instruction Manual
Form 511
September 2009
Type 75A Water Pressure Regulator
Application
The Type 75A is designed to reduce domestic or
industrial water pressures to a constant pressure,
thus protecting plumbing xtures and meters from
high-pressure surges. As shown in Figure 1, it is selfcontained, requiring no external control line
for operation.
Installation
Check the unit for shipment damage. Clean all foreign
material from the pipelines and regulator interior.
Install the Type 75A in a horizontal line with the spring
case above or below the line, and with ow through
the regulator as indicated by the arrow cast on the
body. Coat the external threads with pipe compound
and draw up the connections tightly but not severely.
If a snap-acting valve (solenoid valve) is used in the
system, the snap-acting valve should be installed
upstream of the Type 75A. The Type 75A may be
damaged by high shutoff pressure if a snap-acting
valve is installed downstream.
Type 75A
Adjustment
One spring for each size regulator allows operation
over an outlet pressure range of 20 to 80 psi (1,4 to
5,5 bar). Maximum inlet pressure is 200 psi (13,8 bar).
Minimum operating differential pressure is 5 psi (0,34 bar).
To change the reduced pressure, loosen the adjusting
screw locknut (key 9) and turn the adjusting screw
(key 8) into the spring case to increase the reduced
pressure, or out of the case to decrease it. Re-tighten
the locknut.
www.emersonprocess.com/regulators
W0057-1
Figure 1. Type 75A Water Pressure Regulator
Maintenance
To replace the valve disk (key 13), unscrew the guide
plug (key 3) from the body. The valve disk holder
(key 5) may now be unscrewed from the yoke (key 4). Be
careful not to twist and rupture the diaphragm (key 12).
D100254X012
Type 75A
8
9
10
11
2
7
6
12
14
4
1
17
13
16
5
3
Note
A piece of hex bar stock can be drilled
out and slipped over the disk holder shaft
to t inside the holder. This simplies
removal of the holder from the yoke.
Use the following sizes of hex bar:
NPS 1/2 (DN 15) body – 7/8-inch (22 mm) hex;
NPS 3/4 (DN 20) body – 1-inch (25 mm) hex;
NPS 1 or 1-1/2 (DN 25 or 40) body –
1-1/4-inch (32 mm) hex; NPS 2 (DN 50)
body – 2-inch (51 mm) hex; NPS 2-1/2 (DN 65)
body – 2-1/2-inch (63 mm) hex.
To replace valve disk, unscrew the disk retaining screw
(key 16), remove old disk (key 13), apply gasket sealer
to new disk and install.
To replace the diaphragm, rst remove tension of the
regulator spring (key 11) by turning out the adjusting
screw (key 8). Remove the bolting that holds the spring
case (key 2) to the body and lift off the casing and
regulator spring. Unscrew the diaphragm nut (key 7)
and diaphragm head (key 6). Replace the diaphragm.
Parts Ordering
APPLY GASKALAC
20A5581-B
A0209
NPS 1/2, 3/4, 1, AND 1-1/2 BODY (DN 15, 20, 25, AND 40)
Figure 2. Type 75A Assemblies
When corresponding with your local Sales Ofce
or sales representative about this regulator, always
reference the type number which is found on the
nameplate (key 21).
When ordering replacement parts, reference the key
number of each needed part as found in the following
parts list.
Parts List
Key Description Part Number
1 Body
Bronze
NPS 1/2 (DN 15) 2A940812012
NPS 3/4 (DN 20) 2D226312012
NPS 1 (DN 25) 2V361512012
NPS 1-1/2 (DN 40) 3D174012012
NPS 2 (DN 50) 3D626712012
NPS 2-1/2 (DN 65) 3E231012012
2 Spring Case
Cast Iron
NPS 1/2 (DN 15) 1D878619042
NPS 3/4 (DN 20) 00085719042
NPS 1 (DN 25) 2A480119042
NPS 1-1/2 (DN 40) 3V361319042
NPS 2 and 2-1/2 (DN 50 and 65) 00132019042
Key Description Part Number
3 Guide Plug
Bronze
NPS 1/2 (DN 15) 0W099412012
NPS 3/4 (DN 20) 1A971912012
NPS 1 (DN 25) 1A950812012
NPS 1-1/2 (DN 40) 1A974612012
NPS 2 (DN 50) 1A975212012
NPS 2-1/2 (DN 65) 0D023212012
4 Valve Yoke
Bronze
NPS 1/2 (DN 15) 1A942712012
NPS 3/4 (DN 20) 1A945512012
NPS 1 (DN 25) 1A951412012
NPS 1-1/2 (DN 40) 2V361412012
NPS 2 (DN 50) 2V361612012
NPS 2-1/2 (DN 65) 2V361712012
5 Valve Disk Holder
Bronze
NPS 1/2 (DN 15) 1B590112012
NPS 3/4 (DN 20) 1B590212012
NPS 1 (DN 25) 1B867312012
NPS 1-1/2 (DN 40) 1B867712012
NPS 2 (DN 50) 1B867912012
NPS 2-1/2 (DN 65) 1B869812012
6 Diaphragm Head
NPS 1/2 (DN 15), Steel 1A941524092
NPS 3/4 (DN 20), Cast Iron 1A945619042
NPS 1 (DN 25), Cast Iron 1A950919052
NPS 1-1/2 (DN 40), Cast Iron 1V361219042
NPS 2 and 2-1/2 (DN 50 and 65), Cast Iron 1A975819042
2
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