Victaulic 746 Series User manual

IMPORTANT INFORMATION
WARNING WARNING
• Read and understand all
instructions before attempting
to perform maintenance on any
Victaulic piping products.
• Wear safety glasses, hardhat, and
foot protection.
Failure to follow these instructions
could result in serious personal
injury, property damage, and/or
product failure.
• Depressurize and drain the
piping system before attempting
to remove, adjust, or perform
maintenance on any Victaulic
piping products.
Failure to follow this instruction
could result in serious personal injury
and/or property damage.
The following information is a guide for proper installation of Victaulic Series 746 and Series 746-LPA Dry Accelerators. Always refer to the
installation, maintenance, and testing manual for the applicable valve for detailed system setup, operation, and maintenance instructions.
NOTE: THE SERIES 746 DRY ACCELERATOR SHOULD NOT BE USED ON VALVES EQUIPPED WITH SERIES 776 LOW-PRESSURE
ACTUATORS, SERIES 767 ELECTRIC/PNEUMATIC ACTUATORS, OR SERIES 798 DOUBLE-PNEUMATIC ACTUATORS. FOR THESE
INSTALLATIONS, A SERIES 746-LPA DRY ACCELERATOR MUST BE USED.
Dry Accelerators are quick-opening devices, which exhaust air from the actuator to speed valve operation.
A diaphragm separates the Dry Accelerator into two chambers. The closing chamber contains a compression spring, which maintains the chamber
in the closed position. The closed position is maintained as long as the pressure differential between the opening and closing chambers is less than
3 psi/0.2 Bar.
When the system introduces air pressure into the dry accelerator, air enters the closing chamber and passes through a check valve to the opening
chamber. The check valve, which allows flow into the opening chamber, prevents pressure from escaping the opening chamber. Therefore, air can
escape only through the flow restrictor.
When a rapid loss of system air pressure occurs, such as an open sprinkler, air escapes from the closing chamber faster than it escapes from the
opening chamber. As the sprinkler system’s pressure continues to decay, a differential pressure develops across the diaphragm. When this differential
pressure reaches 3 – 5 psi/0.2 – 0.3 Bar, the opening chamber’s pressure overcomes the compression spring’s closing force, causing the closing
chamber to open to the atmosphere. The closing chamber opens immediately and releases pressure from the actuator, resulting in valve operation.
NOTE: The Series 746-LPA Dry Accelerator must be used only on systems operating below 20 psi/1.4 Bar of air. If air pressure higher than
20 psi/1.4 Bar is required, the Series 746 Dry Accelerator should be used.
I-746.LPA _1
Series 746 and 746-LPA Dry Accelerators
INSTRUCTIONS FOR INSTALLING AND REPAIRING DRY ACCELERATORS
I-746/746-LPAINSTALLATION AND REPAIR KIT INSTRUCTIONS
www.victaulic.com
VICTAULIC IS A REGISTERED TRADEMARK OF VICTAULIC COMPANY. © 2012 VICTAULIC COMPANY. ALL RIGHTS RESERVED. PRINTED IN THE USA.
REV_D

Illustration is exaggerated for clarity
* Denotes components that can be replaced in the field
TO PRESSURE
GAUGE
AIR INLET
CROSS-SECTION WITH UPPER CHAMBER ROTATED
45° AND BOLT REMOVED FOR CLARITY
Opening/Air Chamber
Flow Restrictor*
Piston
O-Ring*
Diaphragm*
Closing Chamber
Actuator Shaft
Compression Spring O-Ring
Seal Support Button-Head
Cap Screw
Closing Chamber Seal
Adjustable Seat
Washer
O-Ring*
Check Valve*
Opening/Air Chamber
Flow Restrictor*
Piston
Diaphragm*
Closing Chamber
Actuator Shaft
Compression Spring O-Ring
Seal Support Button-Head
Cap Screw
Closing Chamber Seal
Adjustable Seat
Washer
Check Valve*
Load Screw
Illustration is exaggerated for clarity
* Denotes components that can be replaced in the field
TO PRESSURE
GAUGE
AIR INLET
CROSS-SECTION WITH UPPER CHAMBER ROTATED
45° AND BOLT REMOVED FOR CLARITY
DESIGN “A”
(INSTRUCTIONS START ON PAGE 7)
DESIGN “B”
(INSTRUCTIONS START ON PAGE 11)
Illustration is exaggerated for clarity
* Denotes components that can be replaced in the field
TO PRESSURE
GAUGE
AIR INLET
Opening/Air Chamber
Flow Restrictor*
Piston
O-Ring*
Diaphragm*
Closing Chamber
Actuator Shaft
Compression Spring O-Ring
Seal Support Button-Head
Cap Screw
Closing Chamber Seal
Adjustable Seat
Washer
Shield*
Built-In Check Valve
DESIGN “C”
(INSTRUCTIONS START ON PAGE 14)
SECTION VIEW DRAWINGS
I-746/746-LPA _2
Series 746 and 746-LPA Dry Accelerators
INSTRUCTIONS FOR INSTALLING AND REPAIRING DRY ACCELERATORS
I-746/746-LPA
INSTALLATION AND REPAIR KIT INSTRUCTIONS
www.victaulic.com
VICTAULIC IS A REGISTERED TRADEMARK OF VICTAULIC COMPANY. © 2012 VICTAULIC COMPANY. ALL RIGHTS RESERVED. PRINTED IN THE USA.
REV_D

AIR SUPPLY REQUIREMENTS FOR SERIES 746
DRY ACCELERATORS
If multiple FireLock Valves are installed with a common air supply,
isolate the systems with a spring-loaded, soft-seated ball check valve to
ensure air integrity for each system. Good practice is to include a ball
valve for isolation and service of each individual system. Multiple valves
require shop air or a tank-mounted air compressor.
Set the air pressure to the required system air pressure. Air pressure
differing from the required system air pressure could delay system
operation response time.
The engineer/system designer is responsible for sizing the compressor
so that the entire system is charged to the required air pressure within
30 minutes. DO NOT oversize the compressor to provide more airflow.
An oversized compressor will slow down or possibly prevent valve
operation.
If the compressor fills the system too fast, it may be necessary to
restrict the air supply. Restricting the air supply will ensure that air
being exhausted from an open sprinkler or manual release valve is not
replaced by the air supply system as fast as it is being exhausted.
COMPRESSOR SIZING
0
2
4
6
8
10
12
14
16
18
20
22
24
26
System Capacity (in gallons)
Required Flow Rate (CFM)
650 600 550 500 450 400 350 300 250 200 150 100 50
700
750
800
850
900
950
1000
1050
1100
1150
1200
1250
1300
1350 1400 1450 1500
55 psi/379 kPa
40 psi/276 kPa
20 psi/138 kPa
RECOMMENDED AIR PRESSURES
10
12
14
16
18
20
22
24
26
28
30
32
34
36
38
40
42
44
46
48
50
Maximum Water Supply Pressure - psi (Peak)
Air Pressure - psi
525456585 105 125 145 165 185 205 225 245 265 285
NOTICE
• The Series 757P AMTA must not be used in any system
installed with a Series 746 Dry Accelerator, unless a tank and
an air regulator are added.
AIR SUPPLY REQUIREMENTS FOR SERIES
746-LPA DRY ACCELERATORS
The required air pressure for FireLock NXT Valves is 13psi/0.9 Bar
minimum, regardless of the system supply water pressure. Normal
air pressure should not exceed 18psi/1.2 Bar. Failure to maintain air
pressure within the 13psi/0.9 Bar to 18psi/1.2 Bar range may reduce
system operation response time.
Systems with air pressure higher than 18 psi/1.2 Bar may require the
addition of a Series 746-LPA Dry Accelerator. NOTE: The Series 746-
LPA Dry Accelerator must be used only on systems operating below
20 psi/1.4 Bar of air. If air pressure higher than 20 psi/1.4Bar is required,
the Series 746 Dry Accelerator should be used.
If multiple FireLock NXT Valves are installed with a common air supply,
isolate the systems with a spring-loaded, soft-seated ball check valve to
ensure air integrity for each system. Good practice is to include a ball
valve for isolation and service of each individual system. Multiple valves
require shop air or a tank-mounted air compressor.
Set the air pressure to the required system air pressure. Air pressure
differing from the required system air pressure could delay system
operation response time.
The engineer/system designer is responsible for sizing the compressor
so that the entire system is charged to the required air pressure within
30 minutes. DO NOT oversize the compressor to provide more airflow.
An oversized compressor will slow down or possibly prevent valve
operation.
If the compressor fills the system too fast, it may be necessary to
restrict the air supply. Restricting the air supply will ensure that air
being exhausted from an open sprinkler or manual release valve is not
replaced by the air supply system as fast as it is being exhausted.
COMPRESSOR SIZING
0
2
4
6
8
10
12
SYSTEM CAPACITY (in gallons)
REQUIRED FLOW RATE (CFM)
COMPRESSOR REQUIREMENTS
550 300
50
800
1050 1300 1550 1800
20 psi/138 kPa
13 psi/90 kPa
NOTICE
• A tank-mounted air compressor with a Series 757 Regulated
AMTA must be used to supply air to a FireLock NXT Valve
installed with a Series 746-LPA Dry Accelerator.
I-746/746-LPA _3
Series 746 and 746-LPA Dry Accelerators
INSTRUCTIONS FOR INSTALLING AND REPAIRING DRY ACCELERATORS
I-746/746-LPAINSTALLATION AND REPAIR KIT INSTRUCTIONS
www.victaulic.com
VICTAULIC IS A REGISTERED TRADEMARK OF VICTAULIC COMPANY. © 2012 VICTAULIC COMPANY. ALL RIGHTS RESERVED. PRINTED IN THE USA.
REV_D

COMPRESSOR REQUIREMENTS AND SETTINGS FOR SYSTEMS
INSTALLED WITH SERIES 746 OR SERIES 746-LPA DRY
ACCELERATORS
A tank-mounted air compressor with a Series 757 Regulated AMTA
must be used to supply air to system installed with a Series 746 or
Series 746-LPA Dry Accelerator. In the event a compressor becomes
inoperative, a properly sized tank-mounted air compressor provides
the greatest protection, since air can be supplied continuously to the
sprinkler system for an extended time period. In addition, a properly-
sized tank-mounted air compressor prevents clogging of the dry
accelerator’s orifice.
FOR SERIES 746-LPA DRY ACCELERATORS: Set the air regulator
of the Series 757 Regulated AMTA to a maximum of 20 psi/1.4 Bar. If
air pressure higher than 20 psi/1.4Bar is required, the Series 746 Dry
Accelerator should be used.
The air regulator of the Series 757 Regulated AMTA is a relief-type
design. Any pressure in the system that is above the set point of the air
regulator will be released. Therefore, charging the air regulator above
the set point could cause premature operation of a valve installed with a
Series 746 or Series 746-LPA Dry Accelerator.
INSTALLATION
For proper operation and approval, the valve and any accessories must
be installed in accordance with the specific trim diagrams included with
the shipment.
CAUTION
• Make sure no foreign material gets into the pipe nipples and
openings in the accelerator.
• If using any material other than Teflon* tape, use extra
caution so that no material gets into the trim.
Failure to follow these instructions could cause improper valve
operation, resulting in personal injury and/or property damage.
1. Apply a small amount of pipe joint compound or Teflon* tape to
the external threads of all threaded pipe connections. DO NOT get
any tape, compound, or other foreign material into the pipe nipples
and openings in the accelerator.
2. Assemble the Dry Accelerator per the drawing provided.
3. Install the Dry Accelerator into the trim of the actuator in the
location designated on the applicable trim drawing. Make sure the
end of the Dry Accelerator with the vent seal “button” is facing
toward the trim of the actuator.
PLACING THE SYSTEM IN SERVICE
When the system is ready to be placed in service, refer to the
installation, maintenance, and testing manual for the applicable valve for
detailed setup instructions.
*TEFLON IS A REGISTERED TRADEMARK OF THE DUPONT COMPANY.
I-746/746-LPA _4
Series 746 and 746-LPA Dry Accelerators
INSTRUCTIONS FOR INSTALLING AND REPAIRING DRY ACCELERATORS
I-746/746-LPA
INSTALLATION AND REPAIR KIT INSTRUCTIONS
www.victaulic.com
VICTAULIC IS A REGISTERED TRADEMARK OF VICTAULIC COMPANY. © 2012 VICTAULIC COMPANY. ALL RIGHTS RESERVED. PRINTED IN THE USA.
REV_D

Item Qty. Description
1 1 Diaphragm for use in Design “B” Series 746-LPA Dry Accelerators or
Design “B” Series 746 Dry Accelerators
2 1 Diaphragm for use in Design “C” Series 746 Dry Accelerators ONLY
3 1 Shield for use in Design “C” Series 746 Dry Accelerators ONLY
4 1 Diaphragm for use in Design “A” Series 746-LPA Dry Accelerators or
Design “A” Series 746 Dry Accelerators
5 1 Flow Restrictor
6 3 O-Ring
7 1 Check Valve
IMPORTANT INFORMATION - DRY ACCELERATOR REPAIR KIT CONTENTS
The Dry Accelerator Repair Kit is shipped with three different diaphragms that look similar. It is important to determine the correct diaphragm and
other internal components that are required during disassembly of the Series 746 or Series 746-LPA Dry Accelerator.
Items 2 and 3 are packaged in a
separate bag and are used ONLY
for repair of Design “C”
Series 746 Dry Accelerators
2
3
14
567
Ø.10 Hole in Diaphragm
Ø.06 Hole in Diaphragm
*
I-746/746-LPA _5
Series 746 and 746-LPA Dry Accelerators
INSTRUCTIONS FOR INSTALLING AND REPAIRING DRY ACCELERATORS
I-746/746-LPAINSTALLATION AND REPAIR KIT INSTRUCTIONS
www.victaulic.com
VICTAULIC IS A REGISTERED TRADEMARK OF VICTAULIC COMPANY. © 2012 VICTAULIC COMPANY. ALL RIGHTS RESERVED. PRINTED IN THE USA.
REV_D

REMOVING THE SERIES 746 OR SERIES
746-LPA DRY ACCELERATOR FROM SERVICE
CAUTION
• Any activities that require taking the
valve out of service may eliminate the fire
protection provided.
• Before servicing or testing the system, notify
the authority having jurisdiction.
• Consideration of a fire patrol should be given
in the affected areas.
Failure to follow these instructions could result
in serious personal injury and/or property
damage.
CAUTION
• The isolation ball valve MUST remain closed during the
following procedures.
Failure to follow this instruction could cause the valve to false
trip, resulting in property damage.
1. Close the isolation ball valve of the Dry Accelerator.
2. Open the ¼-turn vent ball valve of the Dry Accelerator. Confirm
that the gauge on the accelerator reads 0 psi/0 Bar.
3. Remove the Dry Accelerator from the nipple above the isolation
ball valve.
4. Using a marker, place a mark on the upper (opening/air chamber)
and lower (closing chamber) housings. This mark will aid in
aligning the upper and lower housings during re-assembly.
I-746/746-LPA _6
Series 746 and 746-LPA Dry Accelerators
INSTRUCTIONS FOR INSTALLING AND REPAIRING DRY ACCELERATORS
I-746/746-LPA
INSTALLATION AND REPAIR KIT INSTRUCTIONS
www.victaulic.com
VICTAULIC IS A REGISTERED TRADEMARK OF VICTAULIC COMPANY. © 2012 VICTAULIC COMPANY. ALL RIGHTS RESERVED. PRINTED IN THE USA.
REV_D

REPAIR KIT INSTRUCTIONS - DESIGN “A”
ITEMS NEEDED FROM REPAIR KIT FOR DESIGN “A” DRY
ACCELERATORS
1
2
3
Item Qty. Description
1 1 Check Valve with O-Ring
2 1 Flow Restrictor
3 1 Diaphragm
1. Follow all instructions in the “Removing the Series 746 or Series
746-LPA Dry Accelerator from Service” section.
2. Using a ⁄-inch hex wrench, remove the four cap screws from the
lower housing. Keep these cap screws for re-installation.
3. Separate the lower housing from the upper housing.
4. Using an adjustable wrench, remove and discard the check valve
and o-ring.
5. Remove the load screw. Keep this load screw for re-installation.
I-746/746-LPA _7
Series 746 and 746-LPA Dry Accelerators
INSTRUCTIONS FOR INSTALLING AND REPAIRING DRY ACCELERATORS
I-746/746-LPAINSTALLATION AND REPAIR KIT INSTRUCTIONS
www.victaulic.com
VICTAULIC IS A REGISTERED TRADEMARK OF VICTAULIC COMPANY. © 2012 VICTAULIC COMPANY. ALL RIGHTS RESERVED. PRINTED IN THE USA.
REV_D

6. Using a ⁄-inch hex wrench, remove the cap screw that retains
the piston. Keep this cap screw for re-installation.
7. Remove the piston. Keep this piston for re-assembly.
8. Remove and discard the flow restrictor.
9. Remove and discard the diaphragm.
Actuator
Shaft
Lower Housing/
Closing Chamber
10. Remove any debris from the sealing areas of the lower housing
and actuator shaft with a soft rag and non-abrasive cleaner. Install
the NEW diaphragm (provided with the kit) onto the lower housing.
Make sure the raised portion of the diaphragm is installed toward
the lower housing. Align the holes in the diaphragm with the holes
in the actuator shaft and lower housing.
I-746/746-LPA _8
Series 746 and 746-LPA Dry Accelerators
INSTRUCTIONS FOR INSTALLING AND REPAIRING DRY ACCELERATORS
I-746/746-LPA
INSTALLATION AND REPAIR KIT INSTRUCTIONS
www.victaulic.com
VICTAULIC IS A REGISTERED TRADEMARK OF VICTAULIC COMPANY. © 2012 VICTAULIC COMPANY. ALL RIGHTS RESERVED. PRINTED IN THE USA.
REV_D

11. Align the holes of the piston with the holes in the diaphragm/
actuator shaft.
12. Insert the cap screw into the piston and actuator shaft. Using
a ⁄-inch hex wrench, fully tighten the cap screw. NOTE: Use
caution to prevent the piston/diaphragm assembly from rotating
during tightening of the cap screw.
13. Install the NEW flow restrictor (provided with the kit) into the
piston.
14. Tighten the load screw into the piston to retain the flow restrictor.
O-Ring
15. Make sure the NEW o-ring is installed on the NEW check valve.
16. Using an adjustable wrench, install the NEW check valve with
o-ring into the piston.
I-746/746-LPA _9
Series 746 and 746-LPA Dry Accelerators
INSTRUCTIONS FOR INSTALLING AND REPAIRING DRY ACCELERATORS
I-746/746-LPAINSTALLATION AND REPAIR KIT INSTRUCTIONS
www.victaulic.com
VICTAULIC IS A REGISTERED TRADEMARK OF VICTAULIC COMPANY. © 2012 VICTAULIC COMPANY. ALL RIGHTS RESERVED. PRINTED IN THE USA.
REV_D

17. Align the bolt holes of the upper and lower housings. NOTE:
Since one set of bolt holes is offset, use the marks made in the
“Removing the Series 746 or Series 746-LPA Dry Accelerator from
Service” section to aid in alignment.
18. Insert a cap screw into each of the four holes. Using a ⁄-inch hex
wrench, fully tighten the four cap screws.
19. Follow all instructions in the “Placing the System Back in
Service Section.
I-746/746-LPA _10
Series 746 and 746-LPA Dry Accelerators
INSTRUCTIONS FOR INSTALLING AND REPAIRING DRY ACCELERATORS
I-746/746-LPA
INSTALLATION AND REPAIR KIT INSTRUCTIONS
www.victaulic.com
VICTAULIC IS A REGISTERED TRADEMARK OF VICTAULIC COMPANY. © 2012 VICTAULIC COMPANY. ALL RIGHTS RESERVED. PRINTED IN THE USA.
REV_D

REPAIR KIT INSTRUCTIONS - DESIGN “B”
ITEMS NEEDED FROM REPAIR KIT FOR DESIGN “B” DRY
ACCELERATORS
Item Qty. Description
1 1 Diaphragm
2 1 Check Valve with O-Ring
3 1 Flow Restrictor
4 2 O-Ring
1. Follow all instructions in the “Removing the Series 746 or Series
746-LPA Dry Accelerator from Service” section.
2. Using a ⁄-inch hex wrench, remove the four cap screws from the
lower housing. Keep these cap screws for re-installation.
3. Separate the lower housing from the upper housing.
4. Using an adjustable wrench, remove and discard the check valve
and o-ring.
5. Using a ⁄-inch hex wrench, remove the cap screw that retains
the piston. Keep this cap screw for re-installation.
I-746/746-LPA _11
Series 746 and 746-LPA Dry Accelerators
INSTRUCTIONS FOR INSTALLING AND REPAIRING DRY ACCELERATORS
I-746/746-LPAINSTALLATION AND REPAIR KIT INSTRUCTIONS
www.victaulic.com
VICTAULIC IS A REGISTERED TRADEMARK OF VICTAULIC COMPANY. © 2012 VICTAULIC COMPANY. ALL RIGHTS RESERVED. PRINTED IN THE USA.
REV_D

6. Remove the piston, the two o-rings, the flow restrictor, and the
diaphragm. Keep the piston for re-assembly. Discard the flow
restrictor, diaphragm, and two o-rings.
Actuator
Shaft
Lower Housing/
Closing Chamber
7. Remove any debris from the sealing areas of the lower housing
and actuator shaft with a soft rag and non-abrasive cleaner. Insert
the NEW flow restrictor (provided with the kit) into the actuator
shaft.
8. Install the NEW diaphragm (provided with the kit) onto the lower
housing. Make sure the raised portion of the diaphragm is installed
toward the lower housing. Position the diaphragm so that the
largest hole in the center portion of the diaphragm aligns with the
recess where the flow restrictor is installed.
9. Install a NEW o-ring (provided with the kit) around the flow
restrictor.
10. Install a NEW o-ring (provided with the kit) into the recess in the
piston that IS NOT counterbored.
I-746/746-LPA _12
Series 746 and 746-LPA Dry Accelerators
INSTRUCTIONS FOR INSTALLING AND REPAIRING DRY ACCELERATORS
I-746/746-LPA
INSTALLATION AND REPAIR KIT INSTRUCTIONS
www.victaulic.com
VICTAULIC IS A REGISTERED TRADEMARK OF VICTAULIC COMPANY. © 2012 VICTAULIC COMPANY. ALL RIGHTS RESERVED. PRINTED IN THE USA.
REV_D

11. Align the recesses in the piston with the holes in the diaphragm.
NOTE: The counterbore of the piston must align with the flow
restrictor.
12. Insert the cap screw into the piston and actuator shaft. Using
a ⁄-inch hex wrench, fully tighten the cap screw. NOTE: Use
caution to prevent the piston/diaphragm assembly from rotating
during tightening of the cap screw.
13. Make sure a NEW o-ring is installed on the NEW check valve.
14. Using an adjustable wrench, install the NEW check valve with
o-ring into the piston.
15. Align the bolt holes of the upper and lower housings. NOTE:
Since one set of bolt holes is offset, use the marks made in the
“Removing the Series 746 or Series 746-LPA Dry Accelerator from
Service” section to aid in alignment.
16. Insert a cap screw into each of the four holes. Using a ⁄-inch hex
wrench, fully tighten the four cap screws.
17. Follow all instructions in the “Placing the System Back in
Service Section.
I-746/746-LPA _13
Series 746 and 746-LPA Dry Accelerators
INSTRUCTIONS FOR INSTALLING AND REPAIRING DRY ACCELERATORS
I-746/746-LPAINSTALLATION AND REPAIR KIT INSTRUCTIONS
www.victaulic.com
VICTAULIC IS A REGISTERED TRADEMARK OF VICTAULIC COMPANY. © 2012 VICTAULIC COMPANY. ALL RIGHTS RESERVED. PRINTED IN THE USA.
REV_D

REPAIR KIT INSTRUCTIONS – DESIGN “C”
ITEMS NEEDED FROM REPAIR KIT FOR DESIGN “C” DRY
ACCELERATORS
4
3
2
1
Item Qty. Description
1 1 Diaphragm
2 1 Shield
3 1 O-Ring
4 1 Restrictor
1. Follow all instructions in the “Removing the Series 746 or Series
746-LPA Dry Accelerator from Service” section.
2. Using a ⁄-inch hex wrench, remove the four cap screws from the
lower housing. Keep these cap screws for re-installation.
3. Separate the lower housing from the upper housing.
4. Using a ⁄-inch hex wrench, remove the cap screw that retains
the piston. Keep this cap screw for re-installation.
5. Remove the piston. Keep the piston for re-assembly.
I-746/746-LPA _14
Series 746 and 746-LPA Dry Accelerators
INSTRUCTIONS FOR INSTALLING AND REPAIRING DRY ACCELERATORS
I-746/746-LPA
INSTALLATION AND REPAIR KIT INSTRUCTIONS
www.victaulic.com
VICTAULIC IS A REGISTERED TRADEMARK OF VICTAULIC COMPANY. © 2012 VICTAULIC COMPANY. ALL RIGHTS RESERVED. PRINTED IN THE USA.
REV_D

6. Remove and discard the o-ring and restrictor
7. Remove and discard the shield.
8. Remove and discard the diaphragm.
9. Remove any debris from the sealing areas of the lower housing
with a soft rag and non-abrasive cleaner.
10. Install the NEW diaphragm, provided with the kit, onto the lower
housing. Make sure the raised portion of the diaphragm is installed
toward the lower housing. The largest hole in the center portion
of the diaphragm must align with the whole where the restrictor is
normally installed, as shown above.
11. Install the NEW shield, provided with the kit. Make sure the
three holes in the shield align properly with the three holes in the
diaphragm, as shown above.
I-746/746-LPA _15
Series 746 and 746-LPA Dry Accelerators
INSTRUCTIONS FOR INSTALLING AND REPAIRING DRY ACCELERATORS
I-746/746-LPAINSTALLATION AND REPAIR KIT INSTRUCTIONS
www.victaulic.com
VICTAULIC IS A REGISTERED TRADEMARK OF VICTAULIC COMPANY. © 2012 VICTAULIC COMPANY. ALL RIGHTS RESERVED. PRINTED IN THE USA.
REV_D

12. Install the NEW restrictor, provided with the kit, into the largest
hole of the shield/diaphragm.
13. Install the NEW o-ring, provided with the kit, around the restrictor.
14. Align the holes in the piston with the holes in the shield/
diaphragm. NOTE: The counterbore of the piston must align with
the restrictor, as shown above.
15. Insert the cap screw into the piston assembly. Using a ⁄-inch hex
wrench, fully tighten the cap screw.
16. Align the bolt holes of the upper and lower housings. NOTE:
Since one set of bolt holes is offset, use the marks made in the
“Removing the Series 746 or Series 746-LPA Dry Accelerator from
Service” section to aid in alignment.
17. Insert a cap screw into each of the four holes. Using a ⁄-inch hex
wrench, fully tighten the four cap screws.
18. Follow all instructions in the “Placing the System Back in
Service Section.
I-746/746-LPA _16
Series 746 and 746-LPA Dry Accelerators
INSTRUCTIONS FOR INSTALLING AND REPAIRING DRY ACCELERATORS
I-746/746-LPA
INSTALLATION AND REPAIR KIT INSTRUCTIONS
www.victaulic.com
VICTAULIC IS A REGISTERED TRADEMARK OF VICTAULIC COMPANY. © 2012 VICTAULIC COMPANY. ALL RIGHTS RESERVED. PRINTED IN THE USA.
REV_D

PLACING THE SYSTEM BACK IN SERVICE
1. Re-apply a small amount of pipe joint compound or Teflon* tape
to the nipple above the isolation ball valve. DO NOT get any tape,
compound, or other foreign material into the nipple or openings in
the Dry Accelerator.
2. Install the repaired Dry Accelerator assembly onto the nipple above
the isolation ball valve.
3. Close the ¼-turn vent ball valve of the Dry Accelerator.
4. Open the isolation ball valve of the Dry Accelerator. This will set
the accelerator.
5. Observe the system air pressure over a 24-hour period to confirm
system integrity. If there is degradation in system air pressure, find
and correct all leaks. NOTE: NFPA requires less than 2-psi/14-kPa
leakage in 24 hours.
6. Notify the authority having jurisdiction that the valve has been
placed back in service.
*TEFLON IS A REGISTERED TRADEMARK OF THE DUPONT COMPANY.
I-746/746-LPA _17
Series 746 and 746-LPA Dry Accelerators
INSTRUCTIONS FOR INSTALLING AND REPAIRING DRY ACCELERATORS
I-746/746-LPAINSTALLATION AND REPAIR KIT INSTRUCTIONS
www.victaulic.com
VICTAULIC IS A REGISTERED TRADEMARK OF VICTAULIC COMPANY. © 2012 VICTAULIC COMPANY. ALL RIGHTS RESERVED. PRINTED IN THE USA.
REV_D

TROUBLESHOOTING – SERIES 746 AND SERIES 746-LPA DRY ACCELERATORS
Problem Possible Cause Solution
The valve operates without sprinkler activation. There is a loss of air pressure in the lower inlet chamber of the Dry
Accelerator.
Check for air loss at the lower chamber seal. If a leak is present, turn the
adjustment nut counterclockwise to seal.
Check for any leaks in the system and trim. Conrm that the AMTA is
operating properly.
The Dry Accelerator does not operate within a 5-psi/0.3-Bar pressure
drop in system air pressure.
There is a loss of air pressure in the upper air chamber of the Dry
Accelerator.
Apply soapy water to all joints around the Dry Accelerator to check for
leaks. Repair any leaks and re-test.
The air decay rate of the system is too slow. Make sure there are no restrictions in the remote system test valve
(inspector’s test connection).
If the above procedures do not work, contactVictaulic.
The Dry Accelerator does not set up properly (cannot get pressure
on the upper gauge, and the button pops up immediately when
pressure is introduced).
The Dry Accelerator is installed upside-down. Remove the Dry Accelerator from the trim.Turn the unit around so that the
vent seal“button”is facing down (toward the actuator).
I-746/746-LPA _18
Series 746 and 746-LPA Dry Accelerators
INSTRUCTIONS FOR INSTALLING AND REPAIRING DRY ACCELERATORS
I-746/746-LPA
INSTALLATION AND REPAIR KIT INSTRUCTIONS
www.victaulic.com
VICTAULIC IS A REGISTERED TRADEMARK OF VICTAULIC COMPANY. © 2012 VICTAULIC COMPANY. ALL RIGHTS RESERVED. PRINTED IN THE USA.
REV_D

Series 746 and 746-LPA Dry Accelerators
INSTRUCTIONS FOR INSTALLING AND REPAIRING DRY ACCELERATORS
I-746/746-LPAINSTALLATION AND REPAIR KIT INSTRUCTIONS
I-746/746-LPA
For complete contact information, visit www.victaulic.com
I-746/746-LPA 4603 REV D UPDATED 03/2012 Z000746LPA
VICTAULIC IS A REGISTERED TRADEMARK OF VICTAULIC COMPANY. © 2012 VICTAULIC COMPANY. ALL RIGHTS RESERVED. PRINTED IN THE USA.