Backflow Direct Deringer 20 Technical specifications

4X”– 6” Deringer 20/30 Maintenance Instructions
At Backflow Direct we are committed to making our products as easy to install as possible. We design for
most contingencies, but installation may be different based on your regional regulations or system design.
We are continually improving our products and instructions –please help us by providing recommendations
as to how we can improve or products or instructions.
If you have any difficulties at all, please give us a call. Thank you for purchasing our product!
IMPORTANT NOTE: We use Stainless Steel Hardware where possible. Therefore, it is best to have Silver Anti-
seize available to use on all non-wetted bolts—only a small amount is needed.
WARRANTY INFORMATION: Please visit our website for our official warranty www.backflowdirect.com/warranty
READ INSTRUCTIONS IN FULL BEFORE INSTALLATION.
QUESTIONS? CALL 916-760-4524 M-F 8:00 AM –4:30 PM PST
REV: A | 09/06/2019 | BD-INST-4X2030

4X”-6” Deringer 20/30 Maintenance Instructions
BD-INST-4X2030 | Rev A | 09/06/2019 | Copyright 2011 Backflow Direct, LLC Page 2 of 20
Tools Required: This list is the recommended tools for ease of installation. Other versions of the same tool can be used. For
example, Allen Wrenches instead ofAllen Drive Sockets.
QUESTIONS: Please call us at 916-760-4524 M-F 8:00 AM –4:30 PM PST or email us at [e-mail]
#2 Philips Head Screwdriver
#2 Flathead Screwdriver
Adjustable Wrench
Ratchet
Wood Block - 2” x 4” x 5”
Wood Block – 1” x 2” x 16”
Backflow Direct Test Cock Wrench
Expanding Pipe Pliers
15/16” Socket
1 1/8” Socket

4X”-6” Deringer 20/30 Maintenance Instructions
BD-INST-4X2030 | Rev A | 09/06/2019 | Copyright 2011 Backflow Direct, LLC
Closing Shut-Off Valves Prior to Maintenance
1. Slowly rotate Shut-Off Valve #2 Handle (B) clockwise
to the closed position. Flag perpendicular to flow (A).
2. Slowly rotate Shut-Off Valve #1 Handle (C) clockwise
to the closed position. Flag perpendicular to flow (A).
Note: When yellow/orange position indicator flags are
parallel with the flow of water the shut-off valves are in the
open position. Before doing any maintenance be sure the
yellow or orange flow indicators (flags) are perpendicular
to the flow of water and valve body indicating shut-off
valves are in the closed position (A).
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Note
BC
A
A

4X”-6” Deringer 20/30 Maintenance Instructions
BD-INST-02030 | Rev C | 12/22/2015 | Copyright 2011 Backflow Direct, LLC
Opening Test Cocks and Bleeding All Pressure from the Line Before Maintenance
1. DO NOT OPEN Main Test Cock Number 1,
as it is still subject to line pressure.
2. Using the Backflow Direct test cock wrench or
a small adjustable wrench open (A) Main Test
Cock Number 4. (Test Cock is open when
wrench flats are parallel to water flow through
test cock)
3. Using a #2 Flathead Screwdriver open
Bypass Test Cock Number 2. (Test Cock is
open when screwdriver slot is parallel to
water flow through test cock (B) )
4. Using the Backflow Direct test cock wrench
or a small adjustable wrench open Main
Test Cock Number 3.
5. Using a #2 Flathead Screwdriver open
Bypass Test Cock Number 1.
6. Using the Backflow Direct test cock wrench
or a small adjustable wrench open Main
Test Cock Number 2.
BD-INST-4X2030 | Rev A | 09/06/2019 | Copyright 2011 Backflow Direct, LLC Page 4 of 20
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A
A
B
B

4X”-6” Deringer 20/30 Maintenance Instructions
BD-INST-02030 | Rev C | 12/22/2015 | Copyright 2011 Backflow Direct, LLC
Removing Access Port Cover Plate
1. Using a 15/16”socket wrench loosen all eight bolts on the access port
cover plate (A).
2. Remove bolts and tapered washers (B) and store in a safe place. Be
careful not to lose tapered washers as the access cover will not seal
properly without the tapered washers.
3. Remove access port cover plate (C). Do not remove Access Port O-ring
(D).
B
C
A
BD-INST-4X2030 | Rev A | 09/06/2019 | Copyright 2011 Backflow Direct, LLC Page 5 of 20
D

4X”-6” Deringer 20/30 Maintenance Instructions
BD-INST-02030 | Rev C | 12/22/2015 | Copyright 2011 Backflow Direct, LLC
Removing the First Dual-Action Check Module
1. Use a 15/16”Socket Wrench to loosen the check retainer bolts on
both sides of the valve body (A). Do not completely remove check
retainer bolts from valve body. Merely loosen the bolts until the
ends of the bolts are flush with the inner wall of the valve body(B).
This allows for easy removal of Check Modules.
2. Insert a flathead screwdriver between the inner valve body and the
First Check Module Flange (C), gently coax the First Check
Module in the downstream direction until the First Check Module
can easily be removed from the access port by hand.
A
B
BD-INST-4X2030 | Rev A | 09/06/2019 | Copyright 2011 Backflow Direct, LLC Page 6 of 20
C
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4X”-6” Deringer 20/30 Maintenance Instructions
BD-INST-02030 | Rev C | 12/22/2015 | Copyright 2011 Backflow Direct, LLC
Removing the Second Dual-Action Check Module
1. Use a 1 1/8”Socket Wrench to loosen the Check Retainer Bolts on
each side of the valve body (A). Do not completely remove check
retainer bolts from valve body. Merely loosen the bolts until the
ends of the bolts are flush with the inner wall of the valve body(B).
2. Insert a flathead screwdriver between the inner valve body and the
Second Check Module Flange (C), gently coax the Second Check
Module in the upstream direction until the Second Check Module
can easily be removed from the access port by hand.
A
A
C
BD-INST-4X2030 | Rev A | 09/06/2019 | Copyright 2011 Backflow Direct, LLC Page 7 of 20
B
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4X”-6” Deringer 20/30 Maintenance Instructions
BD-INST-02030 | Rev C | 12/22/2015 | Copyright 2011 Backflow Direct, LLC
Disassembly and Maintenance of By-Pass Check Valve
1. Use an adjustable wrench to
rotate Check Cover (A)
counterclockwise to remove.
2. Examine Cover Plate O-ring (B)
for damage or fouling.
3. Remove Spring (C).
4. Remove Check Poppet
Assembly (D) and examine for
damage or fouling.
5. Examine seat cage (E) for
damage or fouling to the Sealing
Seat. Do not remove unless the
seat cage is being replaced.
6. Reverse the order of above
instructions to reassemble By-
Pass Check Valve.
B
C
D
BD-INST-4X2030 | Rev A | 09/06/2019 | Copyright 2011 Backflow Direct, LLC
A
Page 8 of 20
D

4X”-6” Deringer 20/30 Maintenance Instructions
BD-INST-02030 | Rev C | 12/22/2015 | Copyright 2011 Backflow Direct,
LLC
Disassembly and Maintenance of By-Pass Check Valve (continued)
1. To replace a damaged Red Silicone Poppet Disk, use a #2 Philips Head
Screwdriver to remove the Disk Retaining Screw (A).
2. Remove Disk Retaining Washer (B).
3. Use a Flathead Screwdriver to remove the gasket from Poppet Cavity (C).
4. Install new Red Silicone Poppet Disk (D).
5. Reverse the order of the above instructions to reassemble Check Poppet
Assembly.
6. Reverse the order of the instructions on the previous page to reassemble
Bypass Check Assembly.
A
A
C
D
B
BD-INST-4X2030 | Rev A | 09/06/2019 | Copyright 2011 Backflow Direct, LLC Page 9 of 20

4X”-6” Deringer 20/30 Maintenance Instructions
BD-INST-02030 | Rev C | 12/22/2015 | Copyright 2011 Backflow Direct, LLC
Removing Bypass Meter
1. Using the Ball Valve Handles close the #2 Bypass Ball Valve (A) and
then #1 Bypass Ball Valve (B). (Ball Valve is closed when “T” handle is
perpendicular to water flow through Ball Valve).
2. Using a #2 Flat Head Screwdriver open Bypass Test Cock #2 (C) and
then open Bypass Test Cock #1 (D). (Test Cock is open when
screwdriver slot is parallel to water flow through Test Cock).
3. Using a large wrench or adjustable pliers unscrew and retract Bypass
Meter Coupling Nuts (E) . Remove the Gaskets (F) on both sides of
Bypass Meter.
4. Gently remove Bypass Meter (G) from line. It is OK if the bypass
fittings move slightly during the removal process.
5. Reverse order of above instructions to reinstall Bypass Meter.
Remember install Gaskets (F) before threading Meter Coupling Nuts
into place.
B
A
BD-INST-4X2030 | Rev A | 09/06/2019 | Copyright 2011 Backflow Direct, LLC
C
D
E
E
E
F G
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