INSTALLATION, OPERATION AND MAINTENANCE MANUAL (IOM)
Model 1049
Secure-Gard Pilot Operated Vent Valve
ISO Registered Company
SECTION I
I. DESCRIPTION AND SCOPE
The Model 1049 Secure-Gard is a pilot operated vent
valve intended for installation on atmospheric and low
pressure storage tanks, vapor recovery systems, and
process systems.
SECTION II
IOM - 1049
01-17
WARNING
The Model 1049 is a low pressure pilot operated valve.
In as such, does not supply vacuum relief. If vacuum
relief is required, it should be provided by a separate
device.
CAUTION
Follow your company’s safety procedures to avoid
injury to personnel or damage to equipment.
II. PRIOR TO INSTALLATION
Remove all packing material inside and outside of the valve prior to installation.
SAFETY WARNING: In addition to your company’s safety procedures, this section includes guidelines that should
be followed during the installation, operation, and maintenance of Valve Concepts, Inc’s Pilot Operated Vent Valve.
It is necessary to completely read and understand these guidelines.
Tank or system over pressure protection is the primary function of pilot operated vent valves. It must be selected to
meet the total pressure flow requirements within the Maximum Allowable Working Pressure of the system on which
it is installed. Consult API Standard 2000 for tank protection sizing procedures. Improperly specified vent valves
may result in structural damage to the tank or system, and may cause severe personal injury or death.
Valves are pre-set at the factory per customer purchase specifications. DO NOT change the set pressure without
consulting the factory or your local VCI representative. Improper adjustment may cause the valve to malfunction.
DO NOT attempt to remove the valve from the tank or process vessel without first bleeding all pressure from the
system. ALTERNATIVE MEANS OF PRESSURE VENTING MUST BE PROVIDED WHEN THE VALVE IS OUT
OF SERVICE.
The valve has been exposed to process while in service. Observe all plant procedures and Material Safety Data
Sheets (MSDS) for the products in the system while inspecting, adjusting, or servicing the valve. Take appropriate
safety precautions regarding eye protection, respiration and skin contact.
SECTION III
III. INSTALLATION
The inlet and outlet flanges are normally standard ANSI 150 lbs. class flanges unless otherwise indicated and
should be connected following accepted piping practices.
The inlet is vertical and the outlet is horizontal. The
valve should be installed in the normal upright position
with the cap at the top of the valve and the valve inlet at
the bottom. The outlet is to the side.
but not to exceed the maximum pressure rating of the
rotameter. (Standard rotameter supplied by Valve
Concepts is rated to 250 psig.) Once the gas source is
connected, the purge flow can be adjusted by turning
the knob at the top of the rotameter and observing the
For valves using the remote sensing port connection,
sense lines should be a 1/2” O.D. tube or larger and the
flow indicator. The purge mechanism is designed not
to affect the set pressure of the vent valve.
length should not exceed fifteen feet. Longer lengths
may be used with larger diameter sense lines. The
sense line should slope downward from the sense port
to the tank to allow condensate, if any, to drain back
into the tank and not block the sensing capability.
When the tank pressure is below set pressure, the main
valve seat will be closed. If the rotameter is mounted
to purge both the pilot sense and discharge lines, there
will be a very small flow to the valve outlet from the
purge mechanism.
VALVES WITH PURGE ROTAMETER
VALVE WITH AIR OR N2 ASSIST:
For valves with a rotameter mounted for purging either
the pilot sense line only or both pilot sense and discharge lines, connect the purge gas source, usually dry
nitrogen, to the 1/4” FNPT connection at the bottom of
the rotameter. The pressure of the purge gas source
must be higher than the set pressure of the vent valve,
For valves with air or nitrogen assist pilot, connect the
gas source to the 1/4” FNPT connection at the inlet of
the filter regulator. The pressure must be a minimum of
5 psig, but not to exceed the maximum pressure rating
of the filter regulator. (The standard filter regulator sup-
plied by Valve Concepts is rated at 300 psig.)
INSTALLATION DIAGRAMS FOR STANDARD ACCESSORIES & CONFIGURATIONS
Standard Confi guration
Internal Sensing, SS Pilot Filter Element and
Pilot Exhaust to Atmosphere
Option 1
With Pilot Exhaust Tubed to Main Valve Outlet
With Manual Blowdown Valve
Option 2
With Remote Sensing
Option 3
2 IOM-1049
INSTALLATION DIAGRAMS FOR STANDARD ACCESSORIES & CONFIGURATIONS
Option 4
With Back Flow Preventer to Prevent Back Flow
through Main Valve and Pilot
Option 5
With Field Test Connection
(Back Flow Preventer Included)
Option 7
With Rotameter to Purge Pilot Sense
and Discharge Lines
Option 8
With Field Test Connection, Back Flow Preventer and
Rotameter to Purge Pilot Sense and Discharge Lines
Option 6
With Rotameter to Purge Pilot Sense
Option A
Internal Sensing, SS Pilot Filter Element, Pilot Exhaust
to Main Valve Outlet with Manual Blowdown Valve
3IOM-1049
SECTION IV
IV. START-UP
Operation of the Model 1049 is automatic once the set
pressure has been set. (The set pressure is bench-set
per the customer’s specifi ed setting at the factory prior
to shipment.) NOTE: The set pressure is defi ned as
the pressure at which the valve should start to open on
increasing tank pressure.
For the valve to be in the closed position, tank pressure
must reach the actuator though the pilot.
Upon initial start-up, the valve may be opened for a
few seconds, but will close when the pressure in the
actuator chamber reaches tank pressure.
To adjust the set pressure, remove the hex cap at the
top of the valve and loosen the jam nut around the
adjusting screw. Clockwise rotation of the adjusting
screw will increase the set pressure. Counter clockwise
rotation will decrease the set pressure. Do not adjust
the set pressure beyond the nameplate range. Tighten
the jam nut after adjustments are made and replace
the hex cap.
For valves with air or nitrogen assist pilot, the gas
source must be connected to the fi lter regulator before
the valve will be in the closed position. (The fi lter
regulator is pre-set at the factory to 5 psig, and the
CA-1 back pressure regulator is pre-set at the factory
to 10 psig.)
SECTION V
V. MAINTENANCE
It is strongly recommended that if the valve needs to
be serviced, that it be sent to the factory or a factory
authorized repair facility. Trained mechanics with
specialized test equipment will ensure that the valve is
accurately set.
The Model 1049 should be periodically checked to
ensure proper operation. The frequency required
depends on the severity of the service conditions. At
least once a year is recommended.
Maintenance procedures hereinafter are based upon
removal of the unit from the vessel where installed.
To disassemble the valve, refer to the appropriate
drawings.
To replace soft goods of the pilot valve:
The pilot assembly may be removed by unscrewing the
nipple (131) from the upper case weldment (201).
WARNING
SPRING UNDER COMPRESSION. Prior to
re mov ing diaphragm case bolts, relieve spring
com pres sion by backing out the adjusting screw.
Failure to do so may result in flying parts that
could cause personal injury.
To disassemble the diaphragm case, relax the
compressed spring by fi rst unscrewing the cap
(105), then loosen the jam nut (114) and back off the
adjusting screw (113). The ring of nuts, lockwashers,
4 IOM-1049
washers, and bolts (109, 110, 121 and 120) around the
periphery can now be removed. Remove the bolts and
lockwashers (120 and 110), holding the spring bonnet
(104) and upper diaphragm case (102) together.
Replace the round gasket (122) and reassemble items
102, 104, 110 and 120.
Remove the set pressure spring (115), spring button
(112), and ring gasket (134) and set to the side. Hold
the wrenching washers (128) with a wrench, and
loosen and remove nut (109). Remove lockwashers
(110), lower spring guide washers (111), wrenching
washers (128), support plates (106), diaphragm (107),
bolt gaskets (126), and spacer (127) and set to the
side. Remove lock washers (110) and bolts (120) from
the pilot body (101) and lower diaphragm case (103).
Remove the seal diaphragm (124), the body gasket
(125) and the spindle assembly (108). Take the o-ring
seat (133) and the bolt gasket (126) off the spindle
assembly (108) and replace with new parts.
Reinstall the spindle assembly (108) with o-ring (133)
and bolt gasket (126). Set new seal diaphragm (124)
over the stem of the spindle assembly and the body
gasket (125) on top of the seal diaphragm (124). Then,
reinstall the lower diaphragm case (103) to the pilot
body (101) with lock washers (110) and bolts (120).
Slide the spacer (127) over the stem of the spindle
assembly and place another new bolt gasket (126) on
top of the spacer. Place the fi rst support plate (106)
on the stem, then the new diaphragm (107), then the
other bolt gasket (126), then the fi nal support plate
(106). Place the wrenching washers (128), lower
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