Watts LF800M4QT User Manual

Installation, Maintenance, & Repair
Series 800M4 and LF800M4

Anti-Siphon Pressure Vacuum Breaker
featuring Replaceable Seats

Sizes: 1⁄2" - 2" (15 - 50mm)
Models: 800M4FR, 800M4QT, LF800M4FR, LF800M4QT

!

WARNING

RP/IS-800M4QT

Read this Manual BEFORE using this equipment.
Failure to read and follow all safety and use information

can result in death, serious personal injury, property
damage, or damage to the equipment.

Keep this Manual for future reference.

Local building or plumbing codes may require modifications to the
information provided. You are required to consult the local building and
plumbing codes prior to installation. If this information is not consistent
with local building or plumbing codes, the local codes should be fol­lowed.

Need for Periodic Inspection/Maintenance: This product must be
tested periodically in compliance with local codes, but at least once per
year or more as service conditions warrant. Corrosive water conditions,
and/or unauthorized adjustments or repair could render the product
ineffective for the service intended. Regular checking and cleaning of the
product’s internal components helps assure maximum life and proper
product function.

Testing

For field testing procedure, refer to Watts installation sheets
IS-TK-DP/DL, IS-TK-9A, IS-TK-99E and IS-TK-99D found on

www.watts.com.

For other repair kits and service parts, refer to our Backflow
Prevention Products Repair Kits & Service Parts price list
PL-RP-BPD found on www.watts.com.

For technical assistance, contact your local Watts representative.

Pressure — Temperature

Working Temperature: 33°F - 140°F (0.5°C - 60°C)

Maximum Pressure: 150psi (10.3 bar)

Minimum Pressure: 15psi (103 kPa)

Watts 800M4QT/

LF800M4QT

1

⁄2", 3⁄4" (15, 20mm)

Watts 800M4QT/

LF800M4QT

1" - 2" (25 - 50mm)

Installation

Requirements:

1. Install 12" (305mm) above highest point of downstream piping
see Fig. 1.

2. Install bonnet side up and allow for accessibility for testing/service.

3. Install where discharge or spillage is not objectionable.

4. Do not undersize supply or oversize the valve in relation to demand.

5. Do not install where backpressure can occur.

6. Protect from freezing - for Freeze Protection specify Model 800M4FR or
LF800M4FR. Freeze protection can also be provided using a WattsBox
insulated enclosure. Send for ES-WB for additional information.

7. ASSE Standard 1020 requires that the atmospheric vent valve remains
open until the valve body pressure exceeds 1 lb. Until this pressure is
reached, some amount of spillage will occur at the atmospheric vent.
In order to minimize this leakage on start-up close the down stream
shutoff valve and open inlet shutoff valve quickly.

Service:

1. Open test cocks to drain in cold climates if only operated seasonally.

2. Replace rubber goods every 5 years.

WattsBox

Fig. 1

Freeze Protection Guidelines

Purging of a PVB Assembly with Pressurized Air

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.

Main Shutoff Valve

Upstream (Inlet) Drain

Union

Flow

Outlet Drain

Valve

▼

12" Minimum Clearance
Above the Highest Point of
Downstream Piping

▼

Zone Control

Valve Pit

Sprinkler System

Piping

Typical Installation

TWS with Watts Series 800M4/LF800M4
Pressure Vacuum Breaker

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.

Watts 800M4QT/LF800M4QT

1" - 2" (25 - 50mm)

Water
Supply

To
Sprinklers

Key

Watts TWS

Drain Port

or

Blow Down

Watts 800M4QT/LF800M4QT

1

⁄2", 3⁄4" (15 - 20mm)

For repair kits and parts, refer to our Backflow

†

Fits 800M4FR/LF800M4FR Model

Watts reserves the right to change or modify product design, construction, specica­tions, or materials without prior notice and without incurring any obligation to make
such changes and modications on Watts products previously or subsequently sold.

*The wetted surface of this product contacted by consumable
water contains less than 0.25% of lead by weight.

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

RP/IS-800M4QT 1318 EDP# 1915087 © 2013 Watts

Prevention Products Repair Kits & Service Parts
price list PL-RP-BPD found on www.watts.com.

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

USA: Tel: [phone] • Fax: [phone] • www.watts.com

Canada: Tel: [phone] • Fax: [phone] • www.watts.ca