General Air Products AMD-1 Instruction manual

Air M inten nce Device
For Dry Pipe Sprinkler Systems,
Air Supervised Preaction Systems, &
Dry Pilot Actuated Deluge Systems
UL Listed nd FM Approved
Manufactured by: General Air Products, Inc.
118 Summit Drive, Exton, PA 19341
Product Description
The enclosed Automatic Air Maintenance Device is a U
isted and FM Approved assembly of valves, nipples,
fittings, and actuators to automatically control the air
pressure in the piping of dry pipe sprinkler systems,
preaction sprinkler systems, or dry pilot actuated deluge
systems.
The Air Maintenance Device is designed to automatically
feed air into the system piping at the required volume and
pressure from an air source such as:
1. An air compressor
2. An air receiver tank
3. A plant air system (owner's air)
When an air receiver tank or plant air is utilized as the air
supply source, the pressure regulator in the Air
Maintenance Device AMD-1 and AMD-1A T
automatically regulates the air pressure to the
designated level. The outlet pressure of the regulator is
field adjustable.
When an electrically-driven air compressor is utilized as
the air supply source, the pressure switch in the Air
Maintenance Device AMD-2, AMD-2A T and AMD-3
automatically causes the air compressor to cut-in or
cut-out at the minimum and maximum air pressures
desired, respectively. The cut-in and cut-out pressures
are field adjustable.
The automatic air supply is directed through a restricted
orifice in the air maintenance device so that upon
activation of a sprinkler, the air supply will not interfere
with the operation of the dry pipe valve, by continuing to
supply high volumes of pressurized air to the piping
system.
It is a recommended safeguard that a low pressure switch
and alarm be installed on dry pipe systems or other air
supervised piping systems. This will cause an alarm to
sound if the pressure falls below a predetermined level.
Oper tion
The Air Maintenance Device provides a continuous but
restricted air supply to the piping system.
The activation of only one sprinkler in a dry pipe system,
will cause the system pressure to diminish to the point
where the dry pipe valve will “trip”, thereby filling the
system piping with water.
Small piping system air leaks will be compensated for by
the automatic air feed provided the air leaks do not
exceed the restricted air supply.
Technic l D t
Model: AMD-1, AMD-1A T; AMD-2, AMD-2A T; AMD-3
Style: With Air Regulator (AMD-1, AMD-1A T)
With Air Pressure Switch (AMD-2, AMD-2A T,
AMD3)
Approv ls: U , FM
F ctory Oper tion Test:
100% at 35 psi air (AMD-1, AMD-1A T)
100% at 30 & 40 psi air (AMD-2, AMD-2A T,
AMD-3)
Ordering Inform tion
Mfgr. Source: General Air Products, Inc.
Weight: 7 lbs. (AMD-1, AMD-1A T)
11 lbs. (AMD-2, AMD-2A T, AMD-3)
When placing an order, indicate the full product name.
Please specify the quantity, model and style.
Gu r ntee
General Air Products, Inc. will repair and/or replace any
products found to be defective in material or
workmanship within a period of one year from the date of
shipment. Please refer to the current price list for further
details of the warranty.
C ll
1-800-345-8207
for ssist nce
or visit our website for inform tion on these nd ll of our products
www.GENERALAIRPRODUCTS.com
AMDMSTR.3
01/16/13

Design D t
An Air Maintenance Device should be permanently
connected to all dry pipe sprinkler systems to avoid the
possibility of false valve “trips” which may result from
small piping leaks gradually lowering system air
pressure.
An Air Maintenance Device may also be utilized to
automatically control the air supply to the piping system
of an air supervised preaction system or to the pilot lines
of a dry pilot actuated deluge valve.
There are several methods of providing a constant and
controlled supply of air to a sprinkler system as follows:
Air Compressor nd Air M inten nce Device Model
(AMD-2)
The air compressor is connected electrically and
mechanically to the trim of the dry pipe valve, through an
Air Maintenance Device equipped with a pressure switch.
The air pressure switch continuously senses the air
pressure in the piping system and turns the compressor
on if the pressure drops below the cut-in setting and turns
the compressor off if the pressure rises above the cut-out
setting. The cut-in pressure is usually set at the design
air pressure for maintaining the dry pipe valve in the
closed position. The cut-out pressure should be set
approximately 10 psi above the cut-in pressure.
Note: If the dry pipe valve is equipped with an
accelerator, this method of air maintenance is not
recommended. The accelerator is sensitive to a 3 to 5 psi
air pressure drop at a rate of approximately 1 psi in 10
seconds - see AMD-1.
Air Compressor with Air Receiver T nk nd Air
M inten nce Device (Model AMD-1)
The compressor-tank unit is equipped with an integral
pressure switch that controls the pressure in the tank,
maintaining the tank pressure at a level 10 to 15 psi
above the designed air pressure demand of any dry pipe
system supplied by the air compressor tank unit. The
compressor-tank unit is mechanically connected to the
trim of the dry pipe valve, through an Air Maintenance
Device equipped with an air pressure regulator. The
pressure regulator continuously regulates the incoming
air (from the air receiver tank) and maintains the outgoing
air pressure at the pressure setting of the regulator,
usually within an accuracy of 1 psi. The outgoing air
pressure setting is field adjustable from 5 to 75 psi. If the
dry pipe valve is equipped with an accelerator, this
method of air-maintenance is recommended.
AMD-1 Includes Non-Listed Pressure G uge
The AMD-1 includes a non-listed pressure guage for use
with the regulator. Gauge ships uninstalled. To install,
remove the 1/8” plug on the regulator and install the
pressure gauge into the open port.
Pl nt Air Supply nd Air M inten nce Device (AMD-1)
The plant air supply is mechanically connected to the trim
of the dry pipe valve through an Air Maintenance Device
equipped with an air pressure regulator. The pressure
regulator continuously regulates the incoming air and
maintains the outgoing air pressure at the pressure
setting of the regulator, usually within and accuracy of 1
psi. The outgoing air pressure setting is field adjustable
from 5 to 75 psi. The minimum pressure in the plant air
supply must be greater than the design air pressure
required by the dry pipe system since the air pressure
regulator will only regulate pressure downward.
Inst ll tion
Gener l
The Air Maintenance Device must be installed in the air
supply line leading to the dry pipe valve trim, preaction
system piping or dry pilot system piping. The air flow
through the Device must be in the direction shown by the
arrows on the units.
Note: The minimum pipe size is 1/2” diameter, although
3/4” diameter piping will provide a more rapid initial
system fill.
Note: In particularly humid environments, a manual
desiccant air dryer (P/N AD3400) should be properly
installed between the compressor and the dry pipe valve
to remove moisture from the compressed air supply.
Condensed moisture that is allowed to back up into the
compressor cylinder may cause compressor damage.
Cold room / freezer room installations must have a
pre-packaged Dry Air Pac TM which includes an AMD-1.
Consult factory for correct installation procedures.
Model AMD-1 (Pressure Regul tor) (see Fig. 1)
Step 1. Close the 1/4” ball valves (#8) and open the
bypass valve (#7) in the Air Maintenance Device and
open the air supply valve in the dry pipe valve trim.
Step 2. Open the air supply control valve from the plant
air system or air receiver tank to pressurize the system.
Step 3. When the system is pressurized, check the air
pressure gauge to verify the the pressure is at the design
pressure requirement for the system.
(Continued)
AMDMSTR.3
01/16/13

UL Listed nd FM Approved
Manufactured by: General Air Products, Inc.
118 Summit Drive, Exton, PA 19341
Inst ll tion (continued)
Model AMD-1 (Pressure Regul tor)
C ution: C re must be t ken NOT to overpressure
the system bove the regul tor setting when using
the quick fill line.
Note: If necessary to adjust the system pressure ensure
the pressure gauge is installed in the regulator port. Move
the locking nut away from the body of the regulator and
turn the adjustment screw IN to increase the system
pressure and OUT to reduce system pressure
(see Fig. 1).
When reducing from a higher to a lower setting, first
reduce to some pressure less than desired, then bring up
to the desired point.
After achieving the desired pressure setting, lock the
pressure setting by tightening the locking nut.
Step 4. Close the bypass valve (#7) and open the two
1/4” ball valves (#8). The Air Maintenance Device is now
in service.
Model AMD-2 (Pressure Switch) (see Fig. 2)
Step 1. An electrical power circuit should be installed
using the pressure switch to control the compressor
motor in accordance with the National Electric Code
and/or the requirements of the local Authority Having
Jurisdiction. Consult factory for specific
recommendations.
Step 2. Close the 1/4” ball valves (#18) and open the
bypass valve (#17) in the Air Maintenance Device and
open the air supply valve in the dry pipe valve trim.
Step 3. Energize the branch circuit to the pressure switch
to start the compressor and pressurize the system.
Step 4. When the system is pressurized, the pressure
switch will cut-out and stop the compressor. Note the
cut-out pressure.
Step 5. Open any valve connected to the piping system
(such as the three-way valve for the air gauge on the dry
pipe valve trim) just enough to slowly reduce the air
pressure. Close it immediately when the pressure switch
cuts-in and note the cut-in pressure. Verify the the cut-in
and cut out pressures meet the minimum design
requirements for the system air pressures.
Note: If necessary, adjust the cut-in or the cut-out
pressure. oosen the hex-nut on the cover of the
pressure switch and remove the cover. Adjust the cut-in
pressure by turning the Pressure Adjustment Screw in the
proper direction. Adjust the pressure differential
(difference between cut-in and cut-out pressure) by
turning the Pressure Differential Screw. Consult Factory if
in any doubt.
Step 6. Close the bypass valve (#17) and open the two
1/4” ball valves (#18). The Air Maintenance Device is now
in service.
C re nd M inten nce
The Air Maintenance Device does not require any
regularly scheduled maintenance. However, it is
recommended that proper operation and condition be
periodically verified as follows:
1. Verify that the 3/4” bypass valve is closed, the two 1/4”
ball valves are open and the air supply control valve in
the dry pipe valve trim is open.
2. Verify that the cut-in and cut-out pressures are at the
proper setting, if applicable.
3. Verify that the regulated pressure is at the proper
setting, if applicable.
4. Accumulated moisture should be removed from the
drip leg on the air supply line and the desiccant in the air
dryer should be replaced, if applicable.
5. The strainer should be cleaned.
AMDMSTR.3
01/16/13

AMD1
FLOW
FLOW
MAIN LINE
BYPASS LINE
8
8
7
18
MAIN LINE
AMD2
BYPASS LINE
FLOW
18
FLOW
17
PRESSURE
GAUGE PRESSURE
REGULATOR
LOCKING
NUT
ADJUSTMENT
SCREW
FIGURE 1
FIGURE 2