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Valves & Accessories » Dry Pipe System

G-2 Air Maintenance Device - Model “H-2” & “H-3”

Air Maintenance Device Model H-2, Model H-3

Description and Operation

Globe's Model H-2 and H-3 Air Pressure Maintenance Devices are automatic, field-adjustable devices that control the on-off cycling of an air compressor. They are used to control the supervisory air pressure in a dry pipe sprinkler system, preaction system, or dry pilot line system of a dry pilot sprinkler actuated deluge or preaction valve. The H-2 and H-3 are utilized in applications where it is desirable or necessary to use a small, non-tank mounted compressor that is to be dedicated to the system to be pressurized. The H-2 and H-3 monitor system pressure and automatically cycle the air compressor on and off to maintain system pressure within the preset limits.

The Model H-2 should be specified when the primary air compressor has an unloader as an integral part. After the initial system air pressure has been established, the 1/2" Globe valve is closed. As pressure on the system side of the 1/4" check valve drops, the air pressure switch contacts close, causing the compressor to start. A restricted orifice limits the rate at which air is replaced. When the system air pressure has been re-established, the switch contacts open, stopping the compressor.

Globe's Model H-3 Air Maintenance Device is similar in operation to the Model H-2. The Model H- 3, however, incorporates an unloader valve. This model is selected when the primary air compressor is not equipped with an unloader device. After the compressor has re-established the required air pressure on the system side of the check valve, the air pressure switch contacts open, stopping the compressor and operating a release valve. The release valve vents the compressor head to exhaust the air trapped between the compressor head and the bypass check valve. On the next automatic operating cycle, the compressor will start against atmospheric pressure, thus preventing excessive starting loads.

Approvals

• UL Listed
• FM Approved
• NYC-DOB MEA 335-91-M

Technical Data

• Physical Dimensions
  H-2 - 13 1/2" X 7" (343 mm X 178 mm)
  H-3 - 13 1/8" X 7 7/8" (334 mm X 200 mm)

Specifications

				U.S.	Metric
Minimium Close Pressure				14 PSI	0.98 kg/cm2
Maximum Open Pressure				60 PSI	4.22kg/cm2
Differential Pressure				6-16 PSI	42 - 1.12 kg/cm2
Cut In				30 PSI	2.11 kg/cm2
Cut Out (Adjustable)				40 PSI	2.81 kg/cm2
2 HP	3 HP	5 HP	3 HP	5 HP	2 HP
120V single phase	240V single phase	600V single phase	120V 3 phase	240 - 600V 3 phase	115 - 230V DC

Note: Metric Conversions are Approximate.

Cross Sections

Click image above for a detailed view of this product

Item	Description	Mat'l	P/N		Item	Description	Mat'l	P/N
1	Name Plate	Aluminum	320596		9	¼ Check Valve	Aluminum	320589
2	½ x 3 Nipple	Steel	310304		10	¼ X 1 ½ Nipple	Steel	310101
3	¼ Needle Valve	Brass	320586		11	Pressure Sw itch	Purchase	320597
4	1/4 Union	Steel	311401		12	3/8 X Close Nipple	Steel	55122
5	¼ Close Nipple	Steel	310100		13	½ x ½ x 3/8 Tee	Steel	311309
6	¼ Black Elbow	Steel	311201		14	½ x 2 Nipple	Steel	310302
7	¼ Strainer	Brass	320587		15	½ Globe Valve	Brass	311601
8	Metering Orifice	Brass	320588		16	½ X ½ X ¼ Tee	Steel	311314

Click image above for a detailed view of this product

Item	Description	Mat'l	P/N		Item	Description	Mat'l	P/N
1	Name Plate	Aluminum	320601		10	¼ X 1 ½ Nipple	Steel	310101
2	½ Globe Valve	Brass	311601		11	¼ Strainer	Brass	320587
3	½ Close Nipple	Steel	310300		12	Metering Orifice	Brass	320588
4	½ x ½ x ¼ Tee	Steel	311314		13	¼ Check Valve	Aluminum	320589
5	½ x 2½  Nipple	Steel	310303		14	¼ X ¼ X 3/8 Tee	Steel	311309
6	¼ Needle Valve	Brass	320586		15	3/8 X Close Nipple	Steel	55122
7	¼ Union	Steel	311401		16	Pressure Sw itch	Purchase	320602
8	¼ Close Nipple	Steel	310100		17	Connector Tubing - 19"	Copper	320604
9	¼ Black Elbow	Steel	311201		18	Tube Fitting	Brass	320603

Ordering Information

When ordering please specify the following.

• Quantity
• Model Number

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