12 Series 769 FireLock NXT™ Preaction Valve
30.82
Compressor Requirements and Settings for Series 769 FireLock NXT Preaction
Valves Installed with Series 746 Dry Accelerators
Set the air regulator of the Series 757 Regulated AMTA to 13 psi/90 kPa.
THE SERIES 757P AIR MAINTENANCE TRIM ASSEMBLY WITH PRESSURE SWITCH MUST NOT BE
USED ON A SERIES 769 FIRELOCK NXT PREACTION VALVE INSTALLED WITH A SERIES 746 DRY
ACCELERATOR.
When a Series 769 FireLock NXT Preaction Valve is installed with a Series 746 Dry Accelerator, the Series
757 Regulated AMTA must be used. NOTE: The use of an air regulator with a base or riser-mounted
compressor could cause short cycling, resulting in premature wear of the compressor.
In the event a compressor becomes inoperative, a properly sized tank-mounted air compressor provides
the greatest protection for systems installed with a Series 746 Dry Accelerator. In this situation, air can be
supplied continuously to the sprinkler system for an extended time period. NOTE: The Series 757
Regulated AMTA should be used with a tank-mounted air compressor that supplies air to a Series 769
FireLock NXT Preaction Valve installed with a Series 746 Dry Accelerator.
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 Dry Accelerator.
Settings for Air Supervisory Pressure Switches and Alarm Pressure Switches
1. Air supervisory pressure switches are required for preaction systems and must be set according to the
following notes. NOTE: Switches for Vic-Quick Risers are pre-set at the factory.
1a. Wire the air supervisory pressure switches to activate a low-pressure alarm signal. NOTE: In addition,
the local authority having jurisdiction may require a high-pressure alarm. Contact the local authority hav-
ing jurisdiction for this requirement.
1b. Set the air supervisory pressure switches to activate at 2 – 4 psi/14 – 28 kPa, but not lower than 10 psi/
69 kPa, below the minimum air pressure required.
1c. Wire the alarm pressure switch to activate a water flow alarm.
1d. Set the alarm pressure switch to activate on a pressure rise of 4 – 8 psi/28 – 55 kPa.
Victaulic Series 757 Regulated Air
Maintenance Trim Assembly (AMTA)
Victaulic Series 757P Air Maintenance
Trim Assembly (AMTA) with Pressure Switch
NOTICE NOTICE
• Victaulic recommends a maximum of two Series 769 FireLock
NXT Preaction Valves per Series 757 Regulated AMTA.
• Victaulic recommends a maximum of two Series 769
FireLock NXT Preacttion Valves per Series 757P AMTA with
Pressure Switch.
BILL OF MATERIALS BILL OF MATERIALS
Item Description
Item Description
1
1
/
8
-inch/3.2-mm Restrictor
1
1
/
8
-inch/3.2-mm Restrictor
2 Slow-Fill Ball Valve (Normally Open) 2 Pressure Switch
3 Air Regulator 3 Slow-Fill Ball Valve (Normally Open)
4 Strainer (100 Mesh) 4 Fast-Fill Ball Valve (Normally Closed)
5 Spring-Loaded, Soft-Seated Ball Check Valve 5 Strainer (100 Mesh)
6 Fast-Fill Ball Valve (Normally Closed) 6 Spring Loaded, Soft Seated Ball Check Valve
1
6
5
4
2
3
3
4
5
2
6
1
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