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Typical Installation

Using TWS Hydrant

NOTICE

PVB's must be installed a minimum of 12" (305mm) above the highest 

point of water in the sprinkler system. (See Fig. 1)

Service and Replacement Parts

Internal parts can be removed, repaired or inspected without removing the valve from the piping.

Disassembly

1. Shut off the supply pressure and drain the valve.

2. Remove the two hood screws and the hood.

3.  Place a wrench on the parallel flats of bonnet and stem assembly. 

Turn counter clockwise and remove.

4. Remove the vent assembly.

5.  Press down on the spring retainer and disengage it from the retaining 

lugs. Then turn 90° and remove.

6.  Remove the spring retainer and spring. Note that the large diameter of 

the spring is down on the guide assembly.

7.  Remove the check disc holder and guide assembly.

8. Disassemble the check disc holder assembly.

9.  Remove seat (if required) by turning counterclockwise.

Reassembly

Reassemble in the reverse order utilizing the new parts from the repair kit.

To

Sprinklers

Key

Drain Port

or

Blow Down

Water 

Supply

Watts TWS

TWS with Watts Series 800M4/LF800M4

Pressure Vacuum Breaker

Watts 800M4QT/LF800M4QT

1" - 2" (25 - 50mm)

Watts 800M4QT/LF800M4QT

1

2

", 

3

4

" (15 - 20mm)

Watts reserves the right to change or modify product design, construction, specifica-

tions, or materials without prior notice and without incurring any obligation to make 

such changes and modifications on Watts products previously or subsequently sold.

Fits 800M4FR/LF800M4FR Model

*The wetted surface of this product contacted by consumable 

water contains less than 0.25% of lead by weight.

RP/IS-800M4QT   1318 

EDP# 1915087 

© 2013 Watts

USA:

 Tel: (978) 688-1811 • Fax: (978) 794-1848 • www.watts.com

Canada: 

Tel: (905) 332-4090 • Fax: (905) 332-7068 • www.watts.ca 

Limited Warranty:

 Watts Regulator Co. (the “Company”) warrants each product to be free from defects in material and workmanship under normal usage for a period of one year from the date of 

original shipment.  In the event of such defects within the warranty period, the Company will, at its option, replace or recondition the product without charge.  

THE WARRANTY SET FORTH HEREIN IS GIVEN EXPRESSLY AND IS THE ONLY WARRANTY GIVEN BY THE COMPANY WITH RESPECT TO THE PRODUCT.  THE COMPANY MAKES NO OTHER 

WARRANTIES, EXPRESS OR IMPLIED.  THE COMPANY HEREBY SPECIFICALLY DISCLAIMS ALL OTHER WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE IMPLIED 

WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.

The remedy described in the first paragraph of this warranty shall constitute the sole and exclusive remedy for breach of warranty, and the Company shall not be responsible for any incidental, special 

or consequential damages, including without limitation, lost profits or the cost of repairing or replacing other property which is damaged if this product does not work properly, other costs resulting 

from labor charges, delays, vandalism, negligence, fouling caused by foreign material, damage from adverse water conditions, chemical, or any other circumstances over which the Company has no 

control.  This warranty shall be invalidated by any abuse, misuse, misapplication, improper installation or improper maintenance or alteration of the product.  

Some States do not allow limitations on how long an implied warranty lasts, and some States do not allow the exclusion or limitation of incidental or consequential damages.  Therefore the above 

limitations may not apply to you.  This Limited Warranty gives you specific legal rights, and you may have other rights that vary from State to State.  You should consult applicable state laws to 

determine your rights.  

SO FAR AS IS CONSISTENT WITH APPLICABLE STATE LAW, ANY IMPLIED WARRANTIES THAT MAY NOT BE DISCLAIMED, INCLUDING THE IMPLIED WARRANTIES OF 

MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE, ARE LIMITED IN DURATION TO ONE YEAR FROM THE DATE OF ORIGINAL SHIPMENT.

A Watts Water Technologies Company

WARNING:

 This product contains chemicals known to the 

State of California to cause cancer and birth defects or 

other reproductive harm.

For more information: www.watts.com/prop65

1. Close main shutoff valve.
2.  Open upstream drain, test cocks and isolation ball 

valves to depressurize line.

3. Purge with pressurized line.
4.  Leave test cocks and isolation ball valve handles in 

45° angle to drain ball valves and prevent casting 

damage.

Freeze Protection Guidelines

Purging of a PVB Assembly with Pressurized Air

Flow

Upstream (Inlet) Drain

Outlet Drain 

Valve

12" Minimum Clearance 

Above the Highest Point of 

Downstream Piping

Zone Control

Valve Pit Sprinkler System

Piping

Union

Main Shutoff Valve

For repair kits and parts, refer to our Backflow 

Prevention Products Repair Kits & Service Parts 

price list PL-RP-BPD found on 

www.watts.com.

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