Val-Matic 6-8 Combination Air Valve User Manual

Manual No.

ARCO-OM2-1

Val-Matic®

6”-8” Combination Air Valve

(Single Housing Type)

Operation, Maintenance and

Installation Manual

INTRODUCTION ....................................... 1

RECEIVING AND STORAGE.................... 1

DESCRIPTION OF OPERATION.............. 1

INSTALLATION......................................... 2

VALVE CONSTRUCTION......................... 2

MAINTENANCE ........................................ 4

TROUBLESHOOTING............................... 4

DISASSEMBLY......................................... 4

REASSEMBLY.......................................... 5

PARTS & SERVICE................................... 5

WARRANTY.............................................. 6

VALVE AND MANUFACTURING CORP.

905 Riverside Dr. ● Elmhurst, IL 60126

Phone [phone] ● Fax [phone]

VAL-MATICS 6”-8” COMBINATION AIR VALVE

OPERATION, MAINTENANCE AND INSTALLATION

INTRODUCTION

This manual will provide you with the information
to properly install and maintain the valve to
ensure a long service life. The valve has been
designed with stainless steel trim to give years
of trouble free operation. The Combination Air
Valve is typically mounted at the high points in a
piping system and performs the functions of both
an air release valve and an air/vacuum valve.

The Combination Air Valve automatically vents
air, which accumulates at high points in a
system during its operation. The valve will also
exhaust and admit large quantities (volumes) of
air during filling or draining operations and after
emergency conditions such as a power failure.
Both the air release and air/vacuum functions
are needed to maintain pipeline efficiency while
providing protection from adverse pressure
conditions.

Note: This valve is not intended for fluids
containing suspended solids such as
wastewater. For wastewater and other high
turbidity applications, use Val-Matic Series 800
Wastewater Combination Air Valves.

CAUTION: This valve is not intended

for fuel service or fluids
containing suspended
solids.

The valve is a float operated, resilient seated
valve designed to handle clean fluids. The
Maximum Working Pressure, and Model No. are
stamped on the nameplate for reference.

RECEIVING AND STORAGE

Inspect valves upon receipt for damage in
shipment. Handle all valves carefully without
dropping. Valves should remain boxed, clean
and dry until installed to prevent weather related
damage. For long term storage greater than six
months, the valve must remain in the box and
stored indoors. Do no expose valve to sunlight
or ozone for an extended period.

Figure 1. 6”-8” Combination Air Valve

DESCRIPTION OF OPERATION

The Combination Air Valve is fully automatic and
designed to continuously remove air
accumulating at the high points in a piping
system. It also will exhaust and admit air during
filling and draining of the pipeline or tank.

The valve consists of an air/vacuum valve
mechanism with a full size outlet and an air
release valve mechanism with a small diameter
(i.e. 3/8”) precision orifice. The combination air
valve as shown is Figure 1 is a normally open
valve and has three functions as follows.

1. During system startup, the open valve
will exhaust large volumes of air through
the large outlet. When fluid enters the
valve, the air/vacuum float will rise and
seal against the seat. At the same time
the round float will rise and press the
orifice button against the air release
orifice. The air/vacuum float will remain
closed until the pressure drops close to
zero.

1

2. As air accumulates in the piping system
and enters the valve, the round float
drops and the orifice button breaks
contact with the small orifice.
Accumulated air will vent through the
small outlet in the valve cover while the
system is under pressure. As all of the
air is vented, the round float rises again
and closes the orifice button.

3. When the piping system is drained, both
floats will drop and allow air to rapidly
reenter the piping system through both
the air/vacuum and air release orifices.

INSTALLATION

The installation of the valve is important for its
proper operation. Valves must be installed at
the system high points in the vertical position
with the inlet down. For pipeline service, a vault
with freeze protection, adequate screened
venting, and drainage should be provided.
During closure, some fluid discharge will occur
so vent lines should extend to an open drain
area in plant service. A shutoff valve should be
installed below the valve in the event servicing is
required.

Flanges should be mated with flat-faced pipe
flanges equipped with resilient gaskets. Flange
bolts should be lubricated and lightly turned until
all gaps are eliminated. The tightening of the
bolts should then be done in graduated steps
using the crossover tightening method. 3/4”
bolts require a torque of 40-150 ft-lbs. 7/8” bolts
(model 258C) require a torque of 45-205 ft-lbs.
If leakage occurs, allow gaskets to absorb fluid
and check torque and leakage in 24 hours. Do
not exceed bolt rating or crush gasket more than
50% of its thickness.

VALVE CONSTRUCTION

The standard Combination Air Valve body and
cover are cast iron. See specific Materials List
submitted for the order if other than standard
cast iron construction. The internal metal
components are stainless steel. The orifice
button and seat are resilient Buna-N. The
general details of construction are illustrated in
Figure 2. The body (1) is flanged for connection
to the pipeline. The air/vacuum seat (4) is
retained by retaining screws (8) in the cover (2).
The air release seat (4A) is threaded into the
cover (2) and sealed with the adjustable orifice

button (11), which has a threaded post for
attachment to the orifice button arm (22).

2