FNW X10P Water Hammer Arrestors Owner’s Manual

: September 18, 2024
: FNW

Table of Contents

X10P Water Hammer Arrestors
Specifications
Product Usage Instructions
Sizing Recommendations
Single and Multiple Fixture Branch Runs 20 ft And Shorter
- Example 1:
Multiple Fixture Branch Runs Over 20 ft
- Example 2:
Long Piping Runs (25 ft to 150 ft) To Remove Equipment

X10P Water Hammer Arrestors

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Specifications

Product: FNW Water Hammer Arrestors
Standard: PDI-WH 201, revision 1992
Flow Velocity: Not to exceed 10 FPS
Line Pressure: Branch pressure should not exceed 55 psig

Product Usage Instructions

Sizing Recommendations

1. Determine the total fixture-units required by the branch
based on the number and type of plumbing fixtures to be
protected.

2. Use the provided tables to select the correct size water
hammer arrestor based on the total fixture-units. Round up to the
nearest whole number for fractional fixture-units.

Single and Multiple Fixture Branch Runs 20 ft And Shorter

1. Review fixtures and determine total fixture-units.

2. Select the appropriate size water hammer arrestor from Table
2 based on total fixture-units.

Example 1:

Cold Water Branch: Total Fixture-Units: 26 –
Select P.D.I. B Unit

Hot Water Branch: Total Fixture-Units: 6 –
Select P.D.I. A Unit

Multiple Fixture Branch Runs Over 20 ft

1. Determine total fixture-units for the branch.

2. Select two water hammer arrestors from Table 2 whose combined
fixture-unit ratings are equal to or greater than the demand on the
branch.

Example 2:

Cold Water Branch: Total Fixture-Units: 52 –
Select Two P.D.I. B Units

Hot Water Branch: Total Fixture-Units: 12 –
Select Two P.D.I. A Units

Long Piping Runs (25 ft to 150 ft) To Remove Equipment

1. For branch line pressures under 65 psig, select the
appropriate water hammer arrestor from Table 3 based on nominal
pipe size and overall pipe length to the quick shut-off device.

FAQ

Q: Can I modify the water hammer arrestor?

A: No, modifying the water hammer arrestor in any way can void
the warranty and compromise safety.

Q: What should I do if branch pressures exceed 65 psig?

A: In such cases, it is recommended to use the next larger size
water hammer arrestor to maintain proper branch pressure.

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INSTALLATION INSTRUCTIONS
X10P/X11P
PIPING PRODUCTS

WATER HAMMER ARRESTORS

This instruction manual includes sizing and installation information for FNW water hammer arrestors. The detail presented here is interpreted from The Plumbing and Drainage Institute’s Water Hammer Arrestors Standard PDI-WH 201, revision 1992. It is recommended that this document be reviewed for further sizing, placement and reference data on water hammer arrestors.
CAUTION
1. Verify that the application does not exceed the pressure or temperature rating of the water hammer arrestor.
2. To ensure safety and to maintain warranty, never modify the water hammer arrestor in any way.
3. Always verify installation, sizing and use requirements with local plumbing codes.
STORAGE
If the water hammer arrestors will not be used immediately, the following precautions should be taken:
1. Storage should include protection for threaded or sweat ends so that they are not damaged prior to use.
2. Water hammer arrestors should be protected to safeguard against humidity, moisture, dust, dirt, sand, mud, salt spray, sea water or other forms of corrosive and erosive environments.
SIZING
Sizing recommendations are based on an average flow velocity not exceeding 10 FPS. Ideally, the line pressure in a branch should not exceed 55 psig. To maintain proper branch pressure, a water pressure reducing valve should be installed. If, however, branch pressures exceed 65 psig, the next larger size water hammer arrestor is recommended.
Single and Multiple Fixture Branch Runs 20 ft And Shorter
1. Review the number and type of plumbing fixtures to be protected on a given branch.
2. Using Table 1, determine the total number of fixture-units required by that branch. Note that there may be varying fixtureunit weights depending on whether the branch is a hot water (H.W.) or cold water (C.W.) supply. In addition, be sure to select the correct application type, either Public or Private Use.
3. Use the total fixture-units to determine the correct size water hammer arrestor in Table 2. In the case of fractional fixture-units, always round up to the nearest whole number.

UP TO 20 FEET B A

EXAMPLE 1

Cold Water Branch

· 2 Flush Valve Water Closets at 10 F.U. ea.

20

· 4 Lavatories at 1-1/2 F.U. ea.

6

· Total C.W. Branch Fixture Units

26

Select P.D.I. “B” Unit

Hot Water Branch

· 4 Lavatories at 1-1/2 F.U. ea

6

· Total H.W. Branch Fixture-Units

6

Select P.D.I. “A” Unit

Multiple Fixture Branch Runs Over 20 ft
1. Use the same procedures as above to determine the total fixture-units for a given branch using Table 1.
2. Select two water hammer arrestors from Table 2 whose fixtureunit ratings, when added, are equal to or greater than the demand on the branch. In the case of fractional fixture-units, always round up to the nearest whole number.

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INSTALLATION INSTRUCTIONS
X10P/X11P
PIPING PRODUCTS

WATER HAMMER ARRESTORS

EXAMPLE 2

Cold Water Branch

· 4 Flush Valve Water Closets at 10 F.U. ea

40

· 8 Lavatories at 1-1/2 F.U. ea.

12

· Total C.W. Branch Fixture Units

52

Select Two P.D.I. “B” Units

Hot Water Branch

· 8 Lavatories at 1-1/2 F.U. ea.

12

· Total H.W. Branch Fixture-Units

12

Select Two P.D.I. “A” Units

Long Piping Runs (25 ft to 150 ft) To Remove Equipment
1. For branch line pressures under 65 psig, select the appropriate water hammer arrestor from Table 3 based on the nominal pipe size and overall length of pipe to the quick shut-off device.
2. For branch line pressures between 65 psig and 85 psig, select the appropriate water hammer arrestor from Table 4 based on the nominal pipe size and overall length of pipe to the quick shut-off device.

TABLE 2
FNW Size
1/2″ = D 3/4″ = F 1″ = G 1-1/4″ = H 1-1/2″ = J 2″ = K

OVER 20 FEET

B

A

PDI Size Code

10P

11P

A

B

C

D

E

–

F

–

PDI Fixture Units
1 to 11 12 to 32 33 to 60 61 to 113 114 to 154 155 to 330

TABLE 1

Fixture

Type of Supply Control

Water Closet Water Closet Pedestal Urinal Stall or Water Urinal Stall or Water Urinal
Lavatory Bathtub Shower Head Bathroom Group Bathroom Separate Shower Service Sink Laundry Tubs (1-3) Combination Fixture

Flush Valve Flush Tank Flush Valve Flush Valve Flush Tank
Faucet Faucet Mixing Valve Flush Valve Closet Flush Tank Closet Mixing Valve Faucet Faucet Faucet

Total 10 5 10 5 3 2 4 4 3 –

Public C.W. 10
5 10 5 3 1-1/2 2 2 3 –

Weight in Fixture-Units

H.W. –
1-1/2 3 3 3 –

Total 6 3 1 2 2 8 6 2 3 3

Private C.W. 6 3 1 1-1/2 1 8 6 1 3 3

H.W. 1
1-1/2 2 3 3 2 3 3

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We reserve the right to modify or improve the designs or specifications of our products at any time without notice.

INSTALLATION INSTRUCTIONS
X10P/X11P
PIPING PRODUCTS

WATER HAMMER ARRESTORS
EXAMPLE 3
A 2″ pipe leads from the main to a process tank that is isolated by a quick closing valve. The overall pipe run to the valve is 98 feet. The line pressure is 60 psig and the velocity is 10 FPS. According to Table 3, two P.D.I “F” units should be installed. Had the line pressure been 70 psig, two P.D.I. “F” units and one P.D.I. “E” units should have been selected.

TABLE 3

Water Pressure up to 65 psig

Length of Pipe
1/2″

25′

A

50′

A

70′

B

100′

C

125′

C

150′

D

Nominal Pipe Diameter

3/4″

1″ 1-1/4″ 1-1/2″ 2″

A

B

C

D

E

B

C

D

E

C

D

AE

F

EF

D

E

F

CF

FF

D

F

AF

EF

EFF

E

F

DF

FF

FFF

FF

PROCESS TANK

QUICK CLOSURE VALVE WATER MAIN

TABLE 4

Water Pressure 65 psig to 85 psig

Length of Pipe
1/2″

25′

B

50′

B

70′

C

100′

D

125′

D

150′

E

Nominal Pipe Diameter

3/4″

1″ 1-1/4″ 1-1/2″

B

C

D

E

C

D

E

F

D

E

F

CF

E

F

CF

EF

E

CF

DF

FF

F

CF

FF

DFF

2″ F CF FF EFF BFFF FFFF

INSTALLATION
Placement:
Water hammer arrestors should be placed as close to the source of shock as possible. Both hot and cold water branches should have arrestors. There should be an unobstructed path from the shock source to the water hammer arrestor. In figure 1, two shock waves are allowed at points A and B. Figure 2 shows the proper vertical installation, and figure 3 shows the proper horizontal installation. Water hammer arrestors should not be installed in the inverted position.
In multiple fixture lines, the water hammer arrestor should be installed between the last two fixtures of the branch (as in example 1). On multiple fixture lines requiring two arrestors, one unit should be installed at the mid position of the branch, and the second arrestor should be installed between the last two fixtures of the branch (as in example 2).
Fig. 2
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B A
Fig. 1
Fig. 3 We reserve the right to modify or improve the designs or specifications of our products at any time without notice.

LIMITED WARRANTY
Warranty
Subject to the limitations expressed herein, Seller warrants that products manufactured by Seller shall be free from defects in design, material and workmanship under normal use for a period of one year from installation but in no case shall the warranty period extend longer than eighteen months from the date of sale. This warranty is void for any damage caused by misuse, abuse, neglect, acts of God or improper installation. For the purpose of this section, “Normal Use” means in strict accordance with the installation, operation and maintenance manual. The warranty for all other products is provided by the original equipment manufacturer.
Claim Process and Remedies
Seller shall repair or replace, at its option, any non-conforming or otherwise defective product, upon receipt of notice from Buyer during the Manufacturer’s warranty period at no additional charge. SELLER HEREBY DISCLAIMS ALL OTHER EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS OR FITNESS FOR A PARTICULAR PURPOSE. In order to file a claim under the terms of this Warranty, a claimant must promptly notify FNW that a Product may be defective within 30 days of the suspected failure or defect via the telephone number, mail or website listed below and may be required to submit proof of purchase and/or photographs. · Telephone: 1-800-221-3379 · Mailing Address:
751 Lakefront Commons, Newport News, VA 23606 · Website: fnw.com All products alleged to be defective must be sent to FNW for inspection and testing for determination of the cause of the alleged defect or failure.
Limitation of Liability
UNDER NO CIRCUMSTANCES SHALL EITHER PARTY BE LIABLE TO THE OTHER FOR INCIDENTAL, PUNITIVE, SPECIAL OR CONSEQUENTIAL DAMAGES OF ANY KIND. BUYER HEREBY ACKNOWLEDGES AND AGREES THAT UNDER NO CIRCUMSTANCES, AND IN NO EVENT, SHALL SELLER’S LIABILITY, IF ANY, EXCEED THE NET SALES PRICE OF THE DEFECTIVE PRODUCT(S) PURCHASED DURING THE PREVIOUS CONTRACT YEAR.
Labor Allowance
Seller makes NO ADDITIONAL ALLOWANCE FOR THE LABOR OR EXPENSE OF REPAIRING OR REPLACING DEFECTIVE PRODUCTS OR WORKMANSHIP OR DAMAGE RESULTING FROM THE SAME.
Recommendations by Seller
Seller may assist Buyer in selection decisions by providing information regarding products that it manufactures and those manufactured by others. However, Buyer acknowledges that Buyer ultimately chooses the product’s suitability for its particular use, as normally signified by the signature of Buyer’s technical representative. Any recommendations made by Seller concerning the use, design, application or operation of the products shall not be construed as representations or warranties, expressed or implied. Failure by Seller to make recommendations or give advice to Buyer shall not impose any liability upon Seller.
Excused Performance
Seller will make a good faith effort to complete delivery of the products as indicated by Seller in writing, but Seller assumes no responsibility or liability and will accept no back charge for loss or damage due to delay or inability to deliver, caused by acts of God, war, labor difficulties, accidents, inability to obtain materials, delays of carriers, contractors or suppliers or any other causes of any kind whatever beyond the control of Seller. Under no circumstances shall Seller be liable for any special, consequential, incidental, or indirect damages, losses or expense (whether or not based on negligence) arising directly or indirectly from delays or failure to give notice of delay.