Installation Manual: DVU Series Dump Valves; models ... - FW Murphy

Installation and Operation Manual for 

DVU Series Dump Valves 

Models: DVU150, DVU175, DVU2105, DVU2115 and DVU2120 

Installation 00-02-0483 page 1 of 4 

00-02-0483 

Revised 03-06 

Section 15 

Please read the following information before installing. A visual inspection of this product for damage during shipping is recommended 

before mounting. It is your responsibility to have a qualified person install this unit and make sure it conforms to local codes. 

WARNING 

BEFORE BEGINNING INSTALLATION OF THIS MURPHY PRODUCT 

✔ Disconnect all electrical power to the machine. 

✔ Make sure the machine cannot operate during installation. 

✔ Follow all safety warnings of the machine manufacturer. 

✔ Read and follow all installation instructions. 

Description 

The DVU Series models are pneumatically controlled dump valves. 

The valves open and close automatically by pneumatic control from a 

Murphy L1200NDVOR or similar level controller and dump valve operator. 

Diaphragm actuated, the DVU series dump valves operate at 30–70 psi 

(207–483 kPa) [2.07–4.83 bar] and up to 2000 psi (13.8 MPa) [138 bar] 

vessel pressure (depending on the model). 

A key benefit of this design is a hex union that provides the ability 

to replace the seat without removing the valve from piping. 

Fig. 1 Control Pressure vs. Working Pressure 

Control Pressure (PSIG) 

70 

60 

50 

40 

30 

20 

10 

0 

DVU2105 

500 


GENERAL INFORMATION 

1000 1500 2000 

Vessel Pressure (PSIG) 

Minimum Actuation Pressure 


Model Inlet Outlet Trim Size 

DVU2120 2 NPT 1 NPT 0.436 in. (11 mm) 



DVU175 1 NPT 3/4 NPT 0.359 in. (9 mm) 

DVU150 1 NPT 1/2 NPT 0.359 in. (9 mm) 

DVU150/175 

Fig. 2 Dimensions (all models) 

Pressure 

Inlet Port 

1/8 in.-27 NPT 

F Drain 

Connection 

E 

Plug Seal 

A 

Manual Valve 

Operator 

Vent 

Weep Hole Valve Open/Closed 

Union 

Indicator Button 

C 

D 

B 

(dimension shown G for reference only) 

Model A B C D E F G 

DVU2120 7.50 (191) 8.0 (203) 2.75 (70) 1.0 (25) 2-11.5 NPT 1-11.5 NPT 1.03 



DVU175 7.50 (191) 6.75 (171) 2.06 (52) 1.0 (25) 1-11.5 NPT 3/4”-14 NPT 1.03 

DVU150 7.50 (191) 6.75 (171) 2.06 (52) 1.0 (25) 1-11.5 NPT 1/2”-14 NPT 1.03 

NOTE: Dimensions are in inches and (millimeters) 

Specifications 

Operating Temperature: -30 to 250°F (-34.4 to +121°C) 

Valve Operating Pressure: Refer to chart, Fig 1. 

Maximum Process Pressure: 

DVU2120: 2000 psi (13.8 MPa) [138 bar]. 



DVU150 and DVU175: 1800 psi (12.4 MPa) [124 bar]. 

Flow Characteristics: See chart, page 4 (DVU150/175 models only). 

Body Material: Electroless Nickel Plated 12L14 Carbon Steel 

Internal Wetted Parts: Plug Seal: 90 Durometer Urethane. 

Other: 303 stainless steel; Electroless Nickel Plated 12L14 Carbon Steel 

Shipping Weights: DVU150 and DVU175: 9 lbs. (4 kg.). 

Shipping Weights: DVU2105, DVU2115 and DVU2120: 14 lbs. (6.4 kg.). 

Shipping Dimensions: 7-1/2 x 7-1/2 x 10-3/4 in. (191 x 191 x 274 mm.).

Basic Operation 

As condensate rises in the scrubber, the float 

on the L1200NDVOR rises and trips its pneumatic 

valve. The valve opens allowing pressure 

to enter the dump valve pilot chamber. 

Once the pressure enters the pilot chamber it 

forces the diaphragm and valve stem forward 

thus opening the valve seat (valve open/closed 

indicator button pops out) and releasing condensate 

through the valve stem and out the 

drain. As the condensate level drops, the 

L1200NDVOR pneumatic valve closes to shut 

off the pressure to the dump valve causing it to 

close. 

If for any reason the condensate continues to 

rise beyond normal dump levels, model L1200 

operates the alarm and/or shuts down the 

equipment. 

The L1200NDVOR Filter/Regulator and the 

MURPHYGAGE ® help keep the control pressure 

clean and dry. They also allow the operator 

to adjust pressure to recommended levels. 

NOTE: Always use clean, dry, 

instrument quality gas. 

DVU Series Installation 

TYPICAL INSTALLATION ON GAS COMPRESSORS 

Fig. 3 

Scrubber/Separators 

CAUTION: ALWAYS USE “NON-SPARKING TOOLS” 

WHEN GAS IS KNOWN TO BE PRESENT. 

The following describes the “Direct Mounting” method to the 

tank wall. 

1. Install the valve so the drain connection is on the bottom. Use 

pipe thread sealant on all the connections. 

2. Be sure the unit is screwed tight and does not leak. 

3. Install the piping for the pneumatic input signal into the 

1/8 NPT threaded connection of the pressure inlet port (on 

top of the diaphragm housing of the DVU). 

6. Install a union between the DVU drain connection and the 

condensate out line. Use pipe thread sealant on all the connections. 

The Murphy Gas Compressor Scrubber Level System (SLS) 

The system provides for liquid 

control in gas scrubber 

applications, by dumping liquids 

to drain and protecting 

compressors with a high liquid 

level switch. Wetted metal 

parts are made to survive 

constant use in corrosive 

environments. 

See Bulletin: SLS-04005B for 

more details. 

Filter/Regulator & 

MURPHYGAGE ® 

“Instrument 

Quality Air/Gas 

Supply” 

Pneumatic Level Control 

Float actuated level snap-acting switch 

controls pneumatic pressure to open 

and close dump valve. 

L1200NDVOR: Dump Valve Operator, 

pressure regulator, and pressure indicating 

MURPHYGAGE. ® 

DUMP VALVE INSTALLATION 

Fig. 4 

Typical 

Dump Valve 

Installation 


Vessel Wall 

High Level Shutdown Switch 

Stainless steel float actuated level switches to alarm 

and/or shutdown the equipment. 

L1200: 2” NPT pipe connection; Rated 2000 psi 

(13.7MPa) [137bar]; Class I, Division 1. SPDT 

snap-switch standard. DPDT Optional. 

All Stainless Steel available. 

Pneumatic Dump 

Valves See DVU-01069B 

for more details. 

Two piece union design with manual valve operator 

allows soft plug and hard seat to be replaced without 

disassembling outlet piping or scrubber pipe 

connection. Diaphragm actuated valves operate on 

30-70 psi (207-483 kPa; 2-5 bar). 

Upper Assembly 

(removable) 

Valve 

Union 

Drain 

Connection 

Union 

Pneumatic 

Input Signal 

Maintenance 

Bolt 

Valve Indicator 

Weep Hole 

2-Way (Manual Drain) 

Shutoff Valve 

Control 

Panel 

Condensate Out

CAUTION: THE INSTALLATION AND REPAIR PROCEDURES SHOULD 

ONLY BE PERFORMED BY TRAINED, QUALIFIED, AND EXPERIENCED 

PERSONNEL. THE TRAINING, QUALIFICATION AND EXPERIENCE 

REQUIRED IS FOR WORK AROUND PRESSURE VESSELS, NATURAL GAS, POSSI- 

BLY SOUR GAS, OR ANY SUBSTANCE TO BE FOUND IN THE VESSEL. EXTREME 

CARE MUST BE TAKEN TO INSURE ANY RESIDUAL OR FULL PRESSURE IS 

RELIEVED FROM ALL PARTS OF THE SYSTEM TO BE SERVICED. 

Suggested Tools (Sizes listed are wrench openings. 

Adjustable crescent wrenches, socket and/or end wrench, pipe wrenches, 

flat edge screwdriver with 1/4” blade width, can also be used .) 

Model Valve Body Union Nut Plug Seal Hex Stem Nut 

DVU2120 3” 3” 7/8” 1/2” 

DVU2115 3” 3” 1” 1/2” 

DVU2105 3” 3” 1-1/4” 1/2” 

DVU150/DVU175 2-1/4” 2-1/4” 3/4” 3/8” 

Replacing the Plug and Seat 

1. Close the pressure block valves (suction & discharge valves) on the inlet 

and outlet of the skid. Lock them closed if possible. 

2. Open the blowdown valve to remove pressure from the unit. Lock the 

blowdown valve open if possible. 

3. After taking all possible precautions to insure there is no pressure in the 

vessel. (If the condensate line is pressurized, it must also be blocked and 

locked.) Open the manual drain valve so it bleeds into the vessel so it 

can also be bled down. Disconnect the pneumatic input signal connection 

after insuring it also has been de-pressurized. 

4. Using a back-up wrench on the valve body, with a quick "breaking" 

action loosen the union nut on the valve. There is a "weep" hole in the 

nut. If at any time while loosening and taking off the nut pressure is 

escaping through the "weep" hole, immediately stop loosening the nut. 

Retighten the nut and check the preceding procedures to ensure the pressure 

is bled off the vessel. Never remove the assembly if pressure is 

coming through the weep hole. See Figure 4 on page 2. 

5. With the upper assembly removed from the vessel the plug and/or seat can 

be replaced. Loosen the 9/16” jam nut on the maintenance bolt on top of 

the diaphragm cover. Spin the nut up against the head of the bolt. Tighten 

the bolt to extend the shaft and plug. DO NOT OVERTIGHTEN. 

Fig. 5 

Washer(s)* 

Stem 

Nut 

O-Ring 

Plug 

Seat 

Stem 

Crush Washer Seal 

Stem 

Packing 

Seat butts into here 

O-Ring Seals 

Against Outlet 

*Number of washers varies depending on the model from 1 to 3. 

Seal Washer Maintenance 

Pressure Inlet 

Bolt 

Diaphragm 

1/2" Nut 

Fig. 6 

Backup 

Plate 

1-1/8" or 

1" round nut 

Stem 

Spring 

REPAIR PROCEDURE 

Diaphragm 

Housing 

Diaphragm 

Assembly 


6. Using a back-up wrench on the plug, remove the stem nut on the shaft 

under the plug. Once the stem nut is broken loose, the 9/16” head maintenance 

bolt and top assembly will keep the stem from turning. The plug 

turns freely on the stem once loose. The plug and seat can now be 

removed. All soft seals should be replaced. Refer to kit part numbers 

under service parts on page 4. 

Replacing the Diaphragm 

6A. If the diaphragm is to be replaced, all preceding steps have to be 

done. Additionally, do the following: 

6B. Loosen the 9/16” head maintenance bolt, allowing the diaphragm 

spring to relax, and the stem to retract. Make alignment marks on 

the top and bottom halves of the diaphragm assembly for alignment 

during re-assembly. 

6C. Remove the 8, 7/16" bolts/nuts holding the diaphragm housing 

together. 

6D. Using a straight edge screwdriver, gently separate the 2 halves of 

the diaphragm housing, and remove the top, or outside portion. 

6E. Lift the diaphragm and support plates far enough for the 1-1/8" hex 

or 1” round nut on the bottom of the diaphragm assembly to be 

accessible to a wrench and not have the spring interfere. If it is 

desired to replace the packing, pull the stem all the way out. The 

packing can be easily removed using a small screwdriver to pry the 

packing out. The new packing can be simply pressed in, making 

sure the orientation of the packing installed is the same as the orientation 

of the packing removed. The packing is wider toward the 

plug end. You will have to use the seat to hold the packing in place 

when re-inserting the stem. 

6F. With the 1-1/8" hex or 1” round nut held by a wrench, use a 

wrench to loosen and remove the 1/2" nut on top of the diaphragm. 

The diaphragm can now be removed and replaced. 

6G. With the new diaphragm in place and the 1/2" nut tightened, place 

the assembly, diaphragm down on a clean, smooth sturdy surface. 

6H. Have the seat, plug, washers and stem nut handy (if any of these 

parts are to be replaced, use the old parts for this procedure). Press 

down evenly and smoothly on the bottom of the diaphragm assembly 

to cause stem to come up. Place the seat and plug in place. 

Then push the bottom of the diaphragm assembly down far enough 

to install the washers and stem nut on the stem. Tighten the stem 

nut enough to hold against the diaphragm spring. 

6J. Align the diaphragm holes to the bolt holes (bottom half of the 

housing). Install the upper diaphragm housing using the alignment 

marks from step 6B. Install the 8, 7/16" bolts and nuts. Tighten the 

bolts evenly going from one bolt then 180° around to the next bolt, 

then either 120°or 240° around to the next bolt and so forth until 

all 8 bolts are evenly tight. 

6K. Using the 9/16” head maintenance bolt, tighten, pushing the stem 

out until the 9/16"bolt stops – DO NOT OVERTIGHTEN. 

6L. Remove the stem nut holding the plug. (If old parts were used, prepare 

to install the new parts now.) 

7. Install the seat and plug. Place the O-ring on the stem, followed by the 

washer and stem nut. 

8. Tighten the stem nut. Loosen the 9/16” head maintenance bolt by at least one 

turn past the point where it is no longer in contact with the stem. Tighten the 

9/16" jam nut holding the 9/16” head maintenance bolt. 

9. Replace the crush washer and the O-ring hidden by the union nut. 

NOTE: If pressure or fluid comes out the weep hole of the union nut, 

either the O-ring under the union nut is leaking, or the packing could be 

leaking through the internal weep hole above that O-ring. 

10. The assembly is ready to be re-installed. Check for relative position of 

the pneumatic input signal connections before tightening the union nut.

Fig. 7 

Pressure (psid) 

250 

200 

150 

100 

50 

0 

0 

Part No. Description 


55-00-0237 Seal Kit (includes plug) 

55-00-0236 Diaphragm Kit 










5 

PRESSURE VS. FLOW CHART 

Pressure vs. Flow for DVU150 and DVU175 models only 




Typical Seal Kit includes: Nut, Washer (1 to 3), “O” Ring, Plug and 

Seal, Seat, Crush Washer. 

www.fwmurphy.com 

918.317.4100 Email: sales@fwmurphy.com 

10 15 20 25 30 35 40 45 

Flow (gpm) 

SERVICE PARTS 


Typical Diaphragm Repair Kit includes: 

Diaphragm; Diaphragm Washer (upper), Diaphragm Nut, Diaphragm Plate 

(1 or 2 pcs.), Packing, “O” Ring, Stem, Seal Washer for Maintenance Bolt. 

The DVU Series Valve is included in the 

following Scrubber Levels Systems. 

(Includes L1200, L1200NDVOR, and DVU valve) 

SLS2120: Includes DVU2120 valve 





-LR: Less Regulator option 

Warranty 

A limited warranty on materials and workmanship is given with this FW 

Murphy product. A copy of the warranty may be viewed or printed by going 

to www.fwmurphy.com/support/warranty.htm 

MURPHY, the Murphy logo are registered and/or common law trademarks of Murphy Industries, Inc. This document, 

including textual matter and illustrations, is copyright protected by Murphy Industries, Inc., with all rights reserved. 

(c) 2006 Murphy Industries, Inc. Other third party product or trade names referenced herein are the property of 

their respective owners and are used for identification purposes only.

Installation Manual: DVU Series Dump Valves; models ... - FW Murphy

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