Hydrogen Gauges | McMaster-Carr

A four-digit LCD display allows for easy reading of measurements. The LCD shuts off automatically to extend battery life. Gauges are commonly used with pneumatic regulators, compressors, and in critical processes that require high accuracy, such as hydraulic and laboratory applications.

ABS Plastic Case with Brass Connection—(psi, bar, kg/cm², MPa)

For Use With: Air, Carbon Dioxide, Hydrogen, Nitrogen, Natural Gas
Accuracy: ±1% Full Scale (Grade 1A)

Available Pressure Ranges
Pressure Range
psi	bar	kg/cm²	MPa	Resolution, psi
0 to 145	0 to 10	0 to 10	0 to 1	0.1

							Center Back Connection
Dial Diameter	Pipe Size	Environment Temp. Range, °F	Process Temp. Range, °F	Batteries Included	Mounting Orientation	Features		Each
NPT Male
1 3/4"	1/8	-10° to 140°	-10° to 140°	Yes	Any	5-min. Automatic Shut-Off	000000	000000
1 3/4"	1/4	-10° to 140°	-10° to 140°	Yes	Any	5-min. Automatic Shut-Off	000000	00000

ABS Plastic Case with 304 Stainless Steel Connection—(psi, bar, MPa)

For Use With: Air, Hydrogen, Nitrogen
Accuracy: ±1% Full Scale (Not Graded)

Available Pressure Ranges
Pressure Range
psi	MPa	bar	Resolution, psi
0 to 30	0 to 0.2	0 to 2	0.01
0 to 100	0 to 0.7	0 to 6.9	0.1
0 to 300	0 to 2	0 to 20.7	0.1

							Bottom Connection
Dial Diameter	Pipe Size	Environment Temp. Range, °F	Process Temp. Range, °F	Batteries Included	Mounting Orientation	Features		Each
NPT Male
2 1/2"	1/4	0° to 185°	15° to 140°	Yes	Any	3-min. Automatic Shut-Off, Maximum Reading Recall	00000000	0000000
NPT Male with NIST Certificate
2 1/2"	1/4	0° to 185°	15° to 140°	Yes	Any	3-min. Automatic Shut-Off, Maximum Reading Recall	00000000	000000

Low-Pressure Differential Gauges with Color Indicator

A band of green, yellow, and red provides a clear indication of changes in differential pressure. Gauges are commonly used to indicate clogged filters.

For technical drawings and 3-D models, click on a part number.

Low-Pressure Differential Gauges with Color Indicator

For Use With: Air, Water, Hydraulic Fluid, Carbon Dioxide, Nitrogen, Hydrogen, Argon, and Acetylene
Accuracy: ±5% Full Scale (Not Graded)

	Pressure Range, psi
Pipe Size	Green Band	Yellow Band	Red Band	Max. Pressure, psi	Environment Temp. Range, °F	Process Temp. Range, °F	Ht.	Wd.	Dp.	Case Color		Each
NPT Female
1/4	0-2	2-2.5	2.5-3.5	300	-40° to 200°	-40° to 200°	3 1/4"	3 1/4"	1 1/2"	Black	0000000	000000
1/4	0-3	3-4.5	4.5-5	300	-40° to 200°	-40° to 200°	3 1/4"	3 1/4"	1 1/2"	Black	0000000	00000
1/4	0-6	6-9	9-12	300	-40° to 200°	-40° to 200°	3 1/4"	3 1/4"	1 1/2"	Black	0000000	00000
1/4	0-7.5	7.5-12	12-15	300	-40° to 200°	-40° to 200°	3 1/4"	3 1/4"	1 1/2"	Black	0000000	00000
1/4	0-13	13-20	20-30	300	-40° to 200°	-40° to 200°	3 1/4"	3 1/4"	1 1/2"	Black	0000000	00000
1/4	0-19.5	19.5-29.5	29.5-43	300	-40° to 200°	-40° to 200°	3 1/4"	3 1/4"	1 1/2"	Black	0000000	00000

Low-Pressure Differential Gauges with U-Tube

Also known as manometers, these gauges come with indicating liquid that moves up and down two columns—the difference in height between them is your pressure. They are commonly used to indicate clogged filters.

Magnet-mount gauges can be moved for use in multiple locations. Gauges with barbed tube connection have a flexible body that rolls up for storage or transport.

Nylon Plastic Connection—(in. of H₂O)

For Use With: Air, Argon, Carbon Dioxide, and Hydrogen
Accuracy: Not Rated (Not Graded)

With Barbed Tube Connection for 3/16" Tube ID
Pressure Range, in. of H₂O	Scale Range, in. of H₂O	Numeric Increments, in. of H₂O	Graduation Marks, in. of H₂O	Max. Pressure	Ht.	Max. Process Temp., °F	Gender	Mount Type		Each
0-8	4-0-4	1	0.1	Not Rated	17"	130°	Male	Magnet	0000000	000000
0-12	6-0-6	1	0.1	Not Rated	21"	130°	Male	Magnet	0000000	000000
0-16	8-0-8	1	0.1	Not Rated	25"	130°	Male	Magnet	0000000	000000
0-24	12-0-12	1	0.1	Not Rated	33"	130°	Male	Magnet	0000000	000000
0-30	15-0-15	1	0.1	Not Rated	39"	130°	Male	Magnet	0000000	000000
0-36	18-0-18	1	0.1	Not Rated	45"	130°	Male	Magnet	0000000	000000
0-48	24-0-24	1	0.1	Not Rated	57"	130°	Male	Magnet	0000000	000000
0-60	30-0-30	1	0.1	Not Rated	69"	130°	Male	Magnet	0000000	000000
0-72	36-0-36	1	0.1	Not Rated	81"	130°	Male	Magnet	0000000	000000

Brass Connection—(in. of H₂O)

For Use With: Air, Argon, Carbon Dioxide, and Hydrogen
Accuracy: Not Rated (Not Graded)

With Compression Tube Connection for 1/4" Tube OD
Pressure Range, in. of H₂O	Scale Range, in. of H₂O	Numeric Increments, in. of H₂O	Graduation Marks, in. of H₂O	Max. Pressure, psi	Ht.	Gender	Mount Type		Each
0-8	4-0-4	1	0.1	100	20"	Female	Magnet	0000000	0000000
0-12	6-0-6	1	0.1	100	25"	Female	Magnet	0000000	000000
0-16	8-0-8	1	0.1	100	30"	Female	Magnet	0000000	000000
0-20	10-0-10	1	0.1	100	34"	Female	Magnet	0000000	000000
0-24	12-0-12	1	0.1	100	39"	Female	Magnet	0000000	000000
0-36	18-0-18	1	0.1	100	58"	Female	Magnet	0000000	000000

Easy-Read Tank-Mount Pressure-Regulating
Valves with Flowmeter for Inert Gas

Male Inlet × Female Outlet With One Flowmeter

Female Inlet × Male Outlet With One Flowmeter

For Use With: See Table

Flowmeters let you see the gas flow rate from a distance. These valves automatically reduce a high inlet pressure from compressed gas tanks to a lower, stable outlet pressure. All have Compressed Gas Association (CGA) numbered inlet fittings for secure connections to compressed gas tanks. Choose a valve with the same CGA number as your tank and other system components. They have a gauge for monitoring inlet pressure from the tank.

Single-stage valves reduce pressure in one step, which causes the outlet pressure to fluctuate slightly as you empty the tank. They’re best for applications where a constant outlet pressure isn’t critical.

Valves with one flowmeter are for one piece of equipment on a tank. The flowmeter has a single scale.

Adapters (sold separately) for valves with one flowmeter change the outlet fitting from a 5/8"-18 to 9/16"-18 male connection.

For Use With Helium and Hydrogen

Inlet					Outlet					Material
CGA Number	Location	Thread Direction	Pressure Gauge Range, psi	Stage	Thread Size	Location	Thread Direction	Flow Range, scfh	Number of Flowmeters	Body	Seal	Diaphragm		Each
UNF Female Outlet × NGO Male Inlet
CGA 580	Side	Right Hand	0 to 4,000	Single	5/8"-18	Side	Right Hand	0 to 100 (Helium), 0 to 140 (Hydrogen)	1	Brass	PTFE	Neoprene	000000000	0000000

Optional Adapter

00000000

Each

000000

For Use With Hydrogen

Inlet					Outlet					Material
CGA Number	Location	Thread Direction	Pressure Gauge Range, psi	Stage	Thread Size	Location	Thread Direction	Flow Range, scfh	Number of Flowmeters	Body	Seal	Diaphragm		Each
UNF Male Outlet × NGO Female Inlet
CGA 350	Side	Left Hand	0 to 3,000	Single	9/16"-18	Side	Left Hand	0 to 40	1	Brass	PTFE	Neoprene	000000000	0000000

Optional Adapter

00000000

Each

000000

Tank-Mount Pressure-Regulating Valves for Fuel Gases

For Use With: See Table
Temperature Range: -20° to 120° F

Attach these valves to acetylene, hydrogen, methane, propane, or propylene tanks to reduce a high inlet pressure to a lower, stable outlet pressure. They have Compressed Gas Association (CGA) numbered inlet fittings for secure connections to compressed gas tanks. Choose a valve with the same CGA number as your tank and other system components. Valves come with a gauge to monitor outlet pressure and a gauge to monitor inlet pressure from the tank.

Choose a valve with a maximum outlet pressure that’s approximately twice your application’s normal operating pressure. Your operating pressure should never exceed 75% of the valve’s maximum outlet pressure.

Two-stage valves progressively reduce pressure over two steps for more consistent outlet pressure at all times. They’re often used in applications that require a constant outlet pressure regardless of the tank level.

Valves with a brass body have a longer service life than valves with a brass and steel body.

Single-Stage Valves

Male Outlet × Female Inlet Single-Stage Valve With T-Handle

Inlet				Outlet					Material
CGA Number	Location	Thread Direction	Pressure Gauge Range, psi	Thread Size	Location	Thread Direction	Pressure Range, psi	Pressure Adjustment Method	Body	Seal	Diaphragm		Each
For Use With Hydrogen
UNF Male Outlet × NGO Female Inlet
CGA 350	Side	Left Hand	0 to 4,000	9/16"-18	Side	Left Hand	0 to 125	T-Handle	Brass	PTFE	Rubber	000000	0000000

Two-Stage Valves

Male Outlet × Female Inlet Two-Stage Valve With Knob

Inlet				Outlet					Material
CGA Number	Location	Thread Direction	Pressure Gauge Range, psi	Thread Size	Location	Thread Direction	Pressure Range, psi	Pressure Adjustment Method	Body	Seal	Diaphragm		Each
For Use With Hydrogen and Methane
UNF Male Outlet × NGO Female Inlet
CGA 350	Side	Left Hand	0 to 4,000	9/16"-18	Side	Left Hand	2 to 40	Knob	Brass	Neoprene	Rubber	0000000	0000000

High-Purity Tank-Mount
Pressure-Regulating Valves for Fuel Gases

Single Stage

Two Stage

For Use With: Hydrogen, Methane
Temperature Range: -20° to 120° F

Designed to reduce contaminants in high-purity applications using hydrogen and methane gas, these valves have a stainless steel and brass body with a smooth finish to reduce dust collection and internal components designed to protect the seal and diaphragm from contamination. They’re often used in research sample systems, emission monitoring systems, and chromatography. Valves automatically reduce a high inlet pressure from compressed gas tanks to a lower, stable outlet pressure. All have Compressed Gas Association (CGA) numbered inlet fittings for secure connections to compressed gas tanks. Choose a valve with the same CGA number as your tank and other system components. Outlet fittings are Swagelok® for a leak-free seal around hard metal tubing in high-pressure lines. Also known as instrumentation fittings, Swagelok® fittings are compatible with Parker A-Lok, Gyrolok, Bilok, and Tylok fittings. Valves come with a gauge to monitor outlet pressure and a gauge to monitor inlet pressure from the tank.

Inlet					Outlet
CGA Number	Location	Thread Direction	Pressure Gauge Range, psi	Stage	For Tube OD	Location	Pressure Range, psi	Pressure Adjustment Method		Each
Swagelok® Female Outlet × NGO Female Inlet
Brass/Stainless Steel Body—316 Stainless Steel Diaphragm and PTFE Seal with Relief Valve
CGA 350	Side	Left Hand	0 to 4,000	Single	1/4"	Side	0 to 15	Knob	0000000	0000000
CGA 350	Side	Left Hand	0 to 4,000	Single	1/4"	Side	0 to 125	Knob	0000000	000000
CGA 350	Side	Left Hand	0 to 4,000	Two	1/4"	Side	0 to 15	Knob	0000000	000000
CGA 350	Side	Left Hand	0 to 4,000	Two	1/4"	Side	0 to 125	Knob	0000000	000000
CGA 350	Side	Left Hand	0 to 4,000	Two	1/4"	Side	0 to 500	Knob	0000000	000000

Pressure-Regulating Valves for Fuel Gases

With T-Handle

For Use With: See Table
Temperature Range: See Table

Install these valves directly in gas distribution pipelines for acetylene, hydrogen, or propane. They automatically reduce a high inlet pressure to a lower, stable outlet pressure. Valves have two outlets to fit various pipe configurations and come with a plug to close the unused outlet. The gauge monitors outlet pressure. All valves are single stage and reduce pressure in one step, which causes the outlet pressure to fluctuate.

	Inlet			Outlet
For Use With	Pipe Size	Location	Max. Pressure, psi	Pipe Size	Location	Pressure Adjustment Method	Pressure Gauge Range, psi	Temperature Range, ° F	End-to-End Lg.	Port-to-Port Lg.		Each
NPT Female
Brass Body—Stainless Steel Diaphragm and Neoprene Seal
Hydrogen, Propane	1/4	Side	500	1/4	Bottom, Side	T-Handle	0 to 60	0° to 120°	2.40"	1.01"	0000000	000000
Hydrogen, Propane	1/4	Side	500	1/4	Bottom, Side	T-Handle	0 to 200	0° to 120°	2.40"	1.01"	0000000	00000

About Pressure Gauges

About Pipe Size

About Gas Regulators

Digital High-Accuracy Pressure Gauges

Low-Pressure Differential Gauges with Color Indicator

Low-Pressure Differential Gauges with U-Tube

Easy-Read Tank-Mount Pressure-RegulatingValves with Flowmeter for Inert Gas

Tank-Mount Pressure-Regulating Valves for Fuel Gases

High-Purity Tank-MountPressure-Regulating Valves for Fuel Gases

Pressure-Regulating Valves for Fuel Gases

Easy-Read Tank-Mount Pressure-Regulating
Valves with Flowmeter for Inert Gas

High-Purity Tank-Mount
Pressure-Regulating Valves for Fuel Gases