34
TROUBLESHOOTING
SERIES 79N ELECTRIC/PNEUMATIC ACTUATOR
TROUBLESHOOTING
SERIES 746 DRY ACCELERATOR
TROUBLESHOOTING
SYSTEM
Problem
Possible Cause
Solution
When you pull up on the auto vent knob,
the knob does not stay in the “UP”
position.
Not enough air is getting to the Series 79N.
There is a broken seal in the auto vent or Series 79N.
Increase the air pressure going into the Series 79N.
If the above procedure does not work, contact
Victaulic.
Water is leaking through the Series 79N
Electric/Pneumatic Actuator.
The air chamber is not set.
The strainer on the Series 79N is clogged.
There is a ripped diaphragm in the Series 79N.
Make sure the air chamber of the Series 79N is set.
Replace the strainer on the Series 79N, per the
instructions on page 33.
If water still leaks through the Series 79N, contact
Victaulic.
No water is passing through the Series
79N Electric/Pneumatic Actuator.
The solenoid is not energized.
The strainer on the piston charge line is clogged.
Activate the electrical portion of the system to
energize the solenoid.
Disassemble and clean the piston charge line
strainer.
The Series 79N opens when air is lost.
The .032 restrictor, which feeds the upper chamber
(to solenoid), is clogged.
Remove the restrictor (item #32 on page 4) from the
trim, and clean out any foreign material that is
trapped.
The Series 79N does not open.
No power is going to the solenoid.
Check all electrical connections to make sure power
is being supplied to the solenoid.
No pressure is on the Series 79N upper
chamber pressure gauge.
The .032 restrictor, which feeds the upper chamber
(to solenoid), is clogged.
Remove the restrictor (item #32 on page 4) from the
trim, and clean out any foreign material that is
trapped.
Problem
Possible Cause
Solution
The system valve operates without
sprinkler activation.
Loss of air pressure in the lower inlet chamber.
Check for air loss at lower chamber seal. If a leak is
present, turn adjustment nut counterclockwise to
seal.
Check for any leaks in system and trim. Confirm
proper operation of air maintenance device.
Dry accelerator does not operate within a
5-psi (34 kPa) pressure drop in system air
pressure.
Loss of air pressure in upper air chamber of dry
accelerator.
Air decay rate of system is too slow.
Apply soapy water to all dry accelerator joints, and
check for leaks. Repair any leaks and re-test.
Make sure there are no restrictions in the inspector’s
test connection.
If the above procedures do not work, contact
Victaulic.
Dry accelerator does not set up properly
(cannot get pressure on upper gauge, and
button pops up immediately when
pressure is introduced).
Dry accelerator is installed upside down.
Remove dry accelerator from trim, and turn unit
around so that the button is facing down (toward
Series 79N).
Problem
Possible Cause
Solution
Valve operates without sprinkler activation.
Loss of air pressure in system or trim.
Pressure switch on air compressor is set low, or
compressor is not operating.
Check for system leaks. Confirm proper operation of
air maintenance device. Consider installing a low-air
supervisory switch.
Increase "ON" setting on pressure switch, and check
compressor for proper operation.
Water leaking from drip check valve.
Water is getting past clapper seal and into
intermediate chamber.
Water is under clapper seal.
Check clapper seal and valve body seat ring for
physical damage or foreign material.
Inspect clapper seal to make sure no water is under
seal. If water is present, remove and replace seal,
per instructions on page 28.
Air leaking from drip check valve.
Air is getting past clapper seal and into intermediate
chamber.
Water is under clapper seal.
Check clapper seal and valve body seat ring for
physical damage or foreign material.
Inspect clapper seal to make sure no water is under
seal. If water is present, remove and replace seal,
per instructions on page 28.
Clapper will not latch closed.
No water pressure on piston.
Auto drain is not set.
Check water pressure in piston charge line.
Set auto drain.
Water leaking from piston assembly.
Diaphragm is damaged.
Contact Victaulic.
Air leaking from piston assembly.
Piston rod seal is damaged.
Contact Victaulic.
DISCONTINUED
PRODUCT
