Farris Engineering Curtiss-Wright 2600 Series User manual

Technical Manual 1098T R1
Pressure Relief Valve
Maintenance Manual

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Table of Contents
Introduction & Safety Tips ..........................................................................1
2600 Series Disassembly Instructions .......................................................2
2600 Series Cutaway Drawing ..................................................................3
Threaded Valve Disassembly Instructions ..................................................4
Threaded Valve Cutaway Drawings ............................................................5
Test Lever Assemblies ...............................................................................6
Cleaning & Lapping Procedures .................................................................7
Testing Procedures ................................................................................ 8-9
1. Introduction
This Maintenance Manual is intended to present information you will
require to keep your Farris valves in proper working order. Generally,
maintenance becomes necessary as a result of dirt or scale in the lines,
exposure to service conditions, or improper installation.
This manual is designed to provide basic maintenance and repair
information for all Farris spring loaded ASME Section VIII Pressure Relief
Valves. In all cases, repairs should only be performed by personnel who
have received proper training. Training programs designed to meet your
needs can be arranged by contacting the Farris Factory.
If a valve repair requires replacement parts, only Farris manufactured
components should be used. Use of parts from other than the original
manufacturer will lead to potentially dangerous operating conditions.
When following these instructions refer to the drawing for your specific
product.
2. Safety Tips
Make sure that the Pressure Relief Valve is isolated from the pressure
source before it is removed.
Wear protective clothing when removing valves from service in order to
prevent coming in contact with any toxic or corrosive fluids which may
be trapped inside the valve.
Stand clear of the discharge side of a Pressure Relief Valve
when testing.
Pressure Relief Valves should always be installed upright in the vertical
position as the internal parts are designed to operate in this position.
Do not carry valves by the test levers.
Make sure all piping is properly supported to avoid placing excessive
stress on the body or bonnet.
3. Inspection
Upon receipt of the valve at the repair facility, a detailed examination
should be made prior to disassembly. Flange facings and threaded
connections should be examined for signs of damage or corrosion. If
possible the valve should be tested to verify its as-received set pressure.
The valve should be examined to determine if the wire seals are still in
place. These seals are designed to prevent unauthorized tampering with
external adjustments.

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4. 2600, 2600L, & 2600S
Series Valves
The disassembly of all valves follows the same basic procedure. This
section pertains to 2600, 2600S, and 2600L Series Valves. Please refer
to Figure 1.
1. Place the valve at a suitable height. The work surface should be clean
and strong enough to handle the weight of the parts and the forces
required during disassembly and assembly.
2. Valves should be secured to the work surface to prevent them
from falling over.
3. Remove all wire seals from external adjustments.
4. Unscrew the cap by turning counterclockwise. For valves with open or
packed lever assemblies see Section 6. Remove the cap gasket.
5. Remove the blow down ring lock screw and gasket. Rotate the blow
down ring up on the nozzle and record the number of notches and/or
turns required for it to hit the disc holder. This number will be used
during assembly to place the blow down ring in the proper location.
6. Measure the distance from the top of the spring adjusting screw to the
top of the bonnet. Use this measurement when reassembling the valve
to approximately duplicate the original set pressure.
7. Using a smooth jaw wrench, hold the spring adjusting screw and
remove the spring adjusting screw jam nut.
8. While holding the stem, remove the spring adjusting screw by
turning counterclockwise.
9. Remove the body hex nuts and lift the bonnet (yoke) off the body.
10. Remove spring and buttons. Note: on some valves the upper and lower
spring buttons are different.
11. Pull up on stem and lift out the trim assembly consisting of the sleeve
guide, stem retainer, disc holder, disc and bellows (if so equipped).
12. Hold the top of the stem retainer and pull up on stem and turn
counterclockwise to remove from the stem retainer. Remove the
sleeve guide.
13. Remove the disc from the disc holder by holding the assembly with the
disc facing down and rotating the disc clockwise with the tip of your
finger. The disc will then drop free of the disc holder. See Figure 1 for
details on O ring seat valves.
14. On all but the “D” and “E” orifice bellows valves, the disc holder and
stem retainer are held together by the disc holder lock screw. Insert
the proper size allen wrench into the opening in the disc holder. Turn
the allen screw into the stem retainer clockwise. Mount the disc holder
in a vise using the machined flats on the side. Insert a rod in the hole in
the stem retainer and unscrew the two parts. On bellows valves the
bellows and gasket can now be removed.
15. Turn the body over and remove the nozzle from the body. Remove the
blow down ring from the nozzle.
16. Remove any body drain plugs and bonnet vent plugs.
17. Proceed to Section 7 for instructions on cleaning and lapping.
18. Reassemble valve in reverse order, making sure that lapped nozzle and
disc seating surfaces are not damaged. All threaded connections
should be coated with an appropriate lubricant. Gaskets and O rings
should be replaced.
19. Proceed to Section 8 for testing procedures.

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Details - Optional O Ring Seats
L through T orifice
D through K orifice
Figure 1: 2600, 2600L & 2600S Series Parts List
1 Body 12 Lock Screw (B.D.R.) 23 Bonnet Gasket
2 Bonnet or Yoke 13 Lock Screw Stud 24 Lock Screw Gasket
3 Cap 14 Stem Retainer 25 Hex Nut (B.D.R.L.S.)
4 Disc 15 Bellows* 26 Lock Screw (Disc Holder)
5 Nozzle 16 Bellows Gasket* 27 Pipe Plug (Body)
6 Disc Holder 17 Spring Button 28 Pipe Plug (Bonnet)*
7 Blow Down Ring (B.D.R.) 18 Body Stud 29 Flat Head Machine Screw
8 Sleeve Guide 19 Hex Nut (Body) 30 O Ring Retainer
9 Stem 20 Spring 31 O Ring Seat Seal
10 Spring Adjusting Screw 21 Cap Gasket 32 Jack Screw Plug
11 Jam Nut (Spr. Adj. Scr.) 22 Body Gasket
*Conventional design does not use bellows and bellows gasket, but does have bonnet pipe plug. Bellows valves do not come with a bonnet pipe plug.
Figure 1: 2600, 2600S & 2600L

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5. Threaded Valves
The disassembly of all valves follows the same basic procedure. This
section pertains to 2700, 2850, 2856, 1890, and 1896M Series Valves.
Please refer to the appropriate drawings.
1. Place the valve at a suitable height. The work surface should be clean
and strong enough to handle the weight of the parts and the forces
required during disassembly and assembly.
2. Mount valve vertically in a vise using the flats on the body.
3. Remove all wire seals from external adjustments.
4. Unscrew the cap by turning counterclockwise. Remove the cap gasket.
For valves with open or packed lever assemblies, see Section 6.
5. Measure the distance from the top of the spring adjusting screw to the
top of the bonnet. Use this measurement when reassembling the valve
to approximately duplicate the original set pressure.
6. Using a smooth jaw wrench, hold the spring adjusting screw and
remove the spring adjusting screw jam nut.
7. While holding the stem with a smooth jaw pliers, remove the spring
adjusting screw by turning counterclockwise.
8. On 2850 & 2856 Series, remove the blow down ring lock screw
and gasket.
9. Thread a pipe into the outlet and turn the bonnet counterclockwise,
removing it from the body.
10. Remove the stem with spring and buttons attached. On Series 2850
and 2856 valves, the upper and lower spring buttons are different.
11. Remove the spring and buttons from the stem.
12. On the 2850 and 2856 Series, the disc is held to the stem with a pin.
The disc will come off when the pin is removed.
13. 2700 Series Only: Remove the body from the vise and invert assembly,
carefully removing the guide which contains the disc and disc holder.
The disc and disc holder may now be removed from the guide.
2850 & 2856 Series Only: Unscrew the blow down ring from the body.
1890 & 1896M Only: Remove the lift stop ring from the guide. Remove
the body from the vise and carefully invert it, allowing the disc to fall
free. Unscrew the guide from the body.
14. Proceed to Section 7 for instructions on cleaning and lapping.
15. Reassemble valve in reverse order making sure that lapped body and
disc seating surfaces are not damaged. All threaded connections
should be properly coated with an appropriate lubricant.
16. Proceed to Section 8 for testing procedures.
Figure 2: Series 1890 & 1896M

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Figure 3: Parts List - Threaded Valves
1 Body 8 Spring Adjusting Screw 15 Grooved Pin
2 Bonnet 9 Jam Nut (Spr. Adj. Scr.) 16 Lift Stop Ring
3 Cap 10 Blow Down Ring 17 Retaining Ring, Stem Shoulder
4 Disc 11 Lock Screw (B.D.R.) 18 Cap Gasket
5 Disc Holder 12 Spring 19 Body Gasket
6 Guide 13 Spring Button 20 Guide Gasket
7 Stem 14 Stem Shoulder 21 B.D.R. Lock Screw Gasket
Series 2700 Series 2850 & 2856
Figure 3

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6. Lever Assemblies - Figure 4
A. 2600 & 2600S Series
Open Lever: Single Acting
150# & 300#LW Flanges
All Sizes Except 8 x 10
Open Lever
Threaded Valves
Packed Lever
All Sizes
Open Lever: Double Acting
1 x 2 thru 6 x 10 300# thru 2500# Flanges
Sizes 8 x 10, All Types
Packed Lever
Threaded Valves
B. Threaded Valves
Parts List - Lever Assemblies
Item Part Name Item Part Name
1 Cap 12 Test Lever Fork
2 Test Lever 13 Lever, RD. HD. Rivet
3 Cam 14 Groove Pin
4 Cam Shaft 15 Set Screw
5 Gland 16 Gland Nut
6 Stem Test Washer 17 Cap Screw
7 Stem Jam Nut 18 Cap Stud
8 Button Head Rivet 19 Fork, RD. HD. Rivet
9 Packing Ring 20 Cotter Pin
10 Plain Washer* 21 Gland Nut Gasket
11 Lever hex Jam Nut* 22 Cap Hex Nut
*These Items used on 2600 with packed lever are not shown.

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Table 1
Part No. Grade Finish Size
18632X1 (055) 3F Roughing 1/2 oz. tube
18633X1 (075) 38-500 Medium 1/2 oz. tube
18634X1 (105) 38-1200 Final 1/2 oz. tube
7. Cleaning & Lapping
Each part should receive a visual examination for signs of wear and
corrosion. Parts that show signs of excessive corrosion or wear should be
replaced with genuine Farris Factory supplied parts.
All parts should be thoroughly cleaned with an appropriate solvent.
Particular attention should be paid to guiding surfaces such as stems,
stem retainers, and guides. These surfaces should be free of corrosion or
signs of pitting.
Stems should be examined to determine if they are straight. The nozzle
(body on screwed valves) should be examined to ensure there is no foreign
matter that could restrict the valve’s flow. All threads should be examined
to make sure there is no damage that will interfere with assembly or
operation of the valve.
Flange facings should be examined for signs of damage that would inhibit
proper sealing. Gaskets and soft goods, such as O ring seals should always
be replaced. Never perform a repair using the old gaskets and O rings.
To ensure proper valve performance, the nozzle (seat) and disc must be
lapped flat to a mirror finish. This can be accomplished using cast iron
lapping blocks, Pyrex lapping glasses or on a lapping machine. These
devices are used in conjunction with special lapping compounds (See
Table 1).
Lapping Procedure:
1. Use a cast iron lapping block or Pyrex lapping glass that is perfectly flat.
2. Select the appropriate compound from Table 1 and place a small
amount on the lap. When lapping the disc, use a light figure eight
motion (Figure 5). Frequently lift the disc away from the glass or block
to get a new bite on the compound.
3. Follow the same procedure when lapping nozzles or screwed valve
bodies except that the lapping block should be placed on the nozzle.
Use the same figure eight motion, frequently lifting the glass or block to
get a new bite on the compound.
4. Lap to a mirror finish. When done, make sure all compound is
completely removed from the parts using a suitable solvent. Handle the
parts with care to avoid scratching the seating surfaces.
Figure 5

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8. Testing Procedures
Testing consists of adjusting the valve set pressure, performing a seat
leakage test, and a back pressure test. The set pressure test is always
performed first.
Set Pressure Test:
1. Set pressure testing must always be performed using the appropriate
test fluid shown below.
2. Mount the valve on the test stand making a note of the set pressure and
cold differential test pressure (CDTP). The valve will be set at the CDTP.
On valves with blow down rings, set the ring two notches down from
contact with the disc holder (2600 Series) or disc (2850 & 2856 Series).
3. Hold the stem tightly and tighten (turn clockwise) the spring adjusting
screw to increase the set pressure. Make sure the stem does not
rotate while tightening the adjusting screw as this can damage the
seat and disc.
4. Slowly raise the test drum pressure and observe the opening (set)
pressure. The set pressure on air and steam is the point at which it
makes an audible pop. For water, the set point is the first continuous
flow of liquid that forms a stream perpendicular to the outlet approxi-
mately 1/16" thick.
5. If necessary, reduce the test drum pressure 25% below the opening
pressure and adjust the spring adjusting screw. Repeat this until the
valve opens at the required pressure, designated as the cold differential
test pressure (CDTP). The set pressure tolerance is equal to +3% of the
set pressure.
Pressure Relief Valve Test Fluids
Service Fluid Test Fluid
Air, gas & vapor Air or gas
Steam Steam*
Liquid Water
Table 2
*Air may be used for ASME Code Section VIII valves.
6. Lock the jam nut in place and pop the valve once more to ensure the
set pressure adjustment was not disturbed.
7. On 2600 Series valves, run the blow down ring down to the original
position recorded during disassembly. For the 2850 & 2856 Series, set
the ring at the following position down from contact with the disc: 3/4"
inlet - 6 notches, 1" & 1 1/2" inlets - 22 notches, and 2" & 3" inlets -
33 notches. Install the cap or lever assembly and wire seal the cap and
blow down ring lock screws to prevent tampering.
Back Pressure Testing:
1. The back pressure test applies to all valves designed to discharge to a
closed system. This includes valves with plain caps and packed lever
assemblies. Open lever valves and valves with exposed springs (open
bonnet) do not require this test.
2. The secondary pressure zone of all valves exceeding 1" inlet size shall
be tested with air or other suitable gas at a pressure of at least 30 psi. A
suitable leak detection solution will be used to verify tightness of all
gasket joints and vent/drain plugs.
3. If leakage is detected at any location, the valve should be reworked to
eliminate the leak path.

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8. Testing Procedures (continued)
Seat Leakage Test:
1. Next perform a seat leakage test. With the valve mounted on the test
stand, attach a blind flange test fixture as shown in Figure 6 (air, gas, &
vapor service valves only). For steam and water seat leakage testing,
see paragraphs 4 and 5.
2. For metal and soft seated valves the pressure is held at 90% of cold
differential test pressure when the CDTP is greater than 50 psig. For
CDTP 50 psig and below, the pressure should be held 5 psig below the
CDTP.
3. Bring the pressure up and hold it for one minute for valves up to 2" inlet
size, 2 minutes for valves from 2 1/2" to 4" inlet size, and 5 minutes for
valves with inlet sizes 6" and larger. Then count the number of bubbles
for one minute. The acceptance criteria for metal seat valves are per the
following table. For O ring and soft seat valves, there should be no
leakage (zero bubbles per minute).
Table 3
Seat Tightness: Air, Gas & Vapor Service
Set Pressure Leakage Rate in Bubbles Per Minute
psig barg Orifice Size ≤ 0.307
Sq. In (200 mm2)
Orifice Size < 0.307
Sq. In (200 mm2)
15 to 1000 1.03 to 68.9 40 20
1500 103 60 30
2000 138 80 40
2500 172 100 50
3000 207 100 60
4000 276 100 80
5000 345 100 100
6000 413 100 100
4. Steam: Test pressure per paragraph 2 shall be applied for 3 minutes
before the seat tightness test. The valve should be observed for leakage
for at least one minute. There should be no visible sign of leakage at the
valve outlet when viewed against a black background.
Where the Code allows ASME Section VIII steam valves to be tested on air,
seat leakage may be verified using the procedure for air, gas, and vapor
service valves as listed in paragraphs 1 to 3.
5. Water: Liquid valves are tested on water. Test pressures per paragraph
2 should be applied for a period of two minutes. There should be no
visible sign of leakage.
Note: When performing the seat leakage test on valves with open levers, a
plain screwed test cap must be used. This will prevent the venting of the
test pressure through the top of the bonnet.
Tube 5/16" (7.9 millimeters)
OD x 0.035 inch
(0.89 millimeter) Wall
Note: The cover plate should be fitted with a
suitable device to relieve body pressure in case
of accidental popping of the valve.
1/2" (12.7 millimeters)
WATER
AIR RECEIVER
Figure 6

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© 2010 Farris Engineering
Printed in U.S.A.
11/10 3M R1
10195 Brecksville Road, Brecksville, OH 44141 USA • Telephone: [phone] • Fax: [phone] • http://farris.cwfc.com
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Offices Worldwide: For a listing of our global sales network, visit our website at http://farris.cwfc.com.
While this information is presented in good faith and believed to be accurate, Farris Engineering, division of Curtiss-Wright Flow Control Corporation, does not guarantee satisfactory
results from reliance on such information. Nothing contained herein is to be construed as a warranty or guarantee, expressed or implied, regarding the performance, merchantability,
fitness or any other matter with respect to the products, nor as a recommendation to use any product or process in conflict with any patent. Farris Engineering, division of
Curtiss-Wright Flow Control Corporation, reserves the right, without notice, to alter or improve the designs or specifications of the products described herein.
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