I-768N
/ Series 768N FireLock NXT
™
Dry Valve
/ Installation, Maintenance, and Testing Manual
TROUBLESHOOTING – SYSTEM
Problem
Possible Cause
Solution
The valve operates without sprinkler activation.
There is a loss of air pressure in the system or trim.
Check for any leaks in the system and trim. Confirm that the AMTA is
operating properly. Consider installing a low-air supervisory switch.
The pressure switch on the air compressor is set too low, or the compressor
is not operating properly.
Increase the “ON” setting of the air compressor’s pressure switch, and check
the air compressor for proper operation.
Water is leaking from the ball drip on the alarm manifold
assembly.
Water is getting past the clapper seal and into the intermediate chamber
of the valve.
Check the clapper seal and valve body seat ring for physical damage and
foreign material.
Water is under the clapper seal.
Inspect the clapper seal to ensure that no water is under the seal. If water is
present, remove and replace the seal. Refer to the “Removing and Replacing
the Clapper Seal” section.
Air is leaking from the ball drip on the alarm manifold assembly.
Air is getting past the clapper seal and into the intermediate chamber of
the valve.
Check the clapper seal and valve body seat ring for physical damage and
foreign material.
Water is under the clapper seal.
Inspect the clapper seal to ensure that no water is under the seal. If water is
present, remove and replace the seal. Refer to the “Removing and Replacing
the Clapper Seal” section.
The clapper will not latch closed.
There is no water pressure on the diaphragm.
Check the water pressure in the charge line. Ensure that the restrictor in the
charge line is clean.
The auto drain is not set.
Set the auto drain by pulling up on the auto drain sleeve.
Water is leaking from the diaphragm assembly.
The diaphragm is damaged.
Contact Victaulic.
Air is leaking from the diaphragm assembly.
The diaphragm is damaged.
Contact Victaulic.
TROUBLESHOOTING – SERIES 776 LOW-PRESSURE ACTUATOR
Problem
Possible Cause
Solution
When air in the system is released, the Series 776 Low-Pressure
Actuator does not trip.
There is a restriction in the piping between the air manifold and the auto
vent of the Series 776 Low-Pressure Actuator.
Remove the air feed nipple and remove any debris. Clean the restrictor
and strainer in the air manifold. Verify that no debris has built up in the air
manifold ports that could be restricting airflow.
When the Auto Vent Sleeve of the Series 776 Low-Pressure
Actuator is pulled up, the screw does not stay set in the “UP”
position.
The Series 776 Low-Pressure Actuator is not receiving enough air.
Increase the air pressure going into the Series 776 Low-Pressure Actuator.
The Series 776 Low-Pressure Actuator has a broken seal.
If the above procedure does not work, contact Victaulic.
Water is leaking through the Series 776 Low-Pressure Actuator.
The air chamber of the Series 776 Low-Pressure Actuator is not set.
Ensure that the vent seal of the Series 776 Low-Pressure Actuator is in the
set position and the air chamber is pressurized.
The strainer on the Series 776 Low-Pressure Actuator is clogged.
Replace the strainer screen of the Series 776 Low-Pressure Actuator. Refer to
the “Replacing the Filter in Series 776 Low-Pressure Actuators” section.
The Series 776 Low-Pressure Actuator has a ripped diaphragm.
If water still leaks through the Series 776 after performing the above
procedures, contact Victaulic.
No water is passing through the Series 776 Low-Pressure Actuator.
The strainer in the priming manifold is clogged.
Disassemble and clean the priming manifold strainer. Refer to the “Cleaning
the Cartridge in the Air and Priming Manifold Assemblies” section.
TROUBLESHOOTING – SERIES 746-LPA DRY ACCELERATOR
Problem
Possible Cause
Solution
The valve operates without sprinkler activation.
There is a loss of air pressure in the lower inlet chamber of the Series
746-LPA 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. Confirm that the AMTA is
operating properly.
The Series 746-LPA Dry Accelerator does not operate within a
0.3-Bar/5-psi pressure drop in system air pressure.
There is a loss of air pressure in the upper air chamber of the Series 746-LPA
Dry Accelerator.
Apply soapy water to all joints around the Series 746-LPA 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, contact Victaulic.
The Series 746-LPA 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 Series 746-LPA Dry Accelerator is installed upside-down.
Remove the Series 746-LPA Dry Accelerator from the trim. Turn the unit
around so that the vent seal “button” is facing down (toward the actuator).
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