Steam Relief Valves | McMaster-Carr

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About Pressure-Relief Valves

Valve With Test Lever

Valve With Swivel Test Lever

For Use With: Steam
Temperature Range: -60° to 400° F

These valves meet ASME Code Section I for use with steam power boilers requiring pressure relief above 15 psi. They spring fully open at the set pressure and remain open until the system pressure is restored below the set pressure. For remote discharge, attach a drain line to the threaded relief port. Valves have a durable bronze body for a long service life.

EPR rubber seals provide better leak protection than brass seals.

Swivel test levers rotate 360° around the valve for use in areas with limited clearance.

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

Inlet			Relief Port
Pipe Size	Location	Maximum Pressure, psi	Pipe Size	Location	Overall Ht.	Test Mechanism	Test Lever Type	Valve Type	Specifications Met	Choose a Set Pressure, psi		Each
NPT Male Inlet and NPT Female Relief Port
Bronze Body—Brass Seal
1/2	Bottom	250	3/4	Side	6 1/2"	Lever	__	Pop Safety	ASME BPVC.I	15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 125, 150, 175, 200, 225, 250	0000000	0000000
1/2	Bottom	250	3/4	Side	7 5/16"	Lever	Swivel	Pop Safety	ASME BPVC.I	15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 125, 150, 175, 200, 225, 250	0000000	000000
3/4	Bottom	250	1	Side	7 1/2"	Lever	__	Pop Safety	ASME BPVC.I	15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 125, 150, 175, 200, 225, 250	0000000	000000
3/4	Bottom	250	3/4	Side	7 5/16"	Lever	Swivel	Pop Safety	ASME BPVC.I	15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 125, 150, 175, 200, 225, 250	0000000	000000
1	Bottom	250	1	Side	7 5/8"	Lever	Swivel	Pop Safety	ASME BPVC.I	15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 125, 150, 175, 200, 225, 250	0000000	000000
1	Bottom	250	1 1/4	Side	8 1/2"	Lever	__	Pop Safety	ASME BPVC.I	15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 125, 150, 175, 200, 225, 250	0000000	000000
1 1/4	Bottom	250	1 1/2	Side	9 5/8"	Lever	__	Pop Safety	ASME BPVC.I	15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 125, 150, 175, 200, 225, 250	0000000	000000
1 1/2	Bottom	250	1 1/2	Side	9 5/8"	Lever	Swivel	Pop Safety	ASME BPVC.I	15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 125, 150, 175, 200, 225, 250	0000000	000000
1 1/2	Bottom	250	2	Side	10 5/8"	Lever	__	Pop Safety	ASME BPVC.I	15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 125, 150, 175, 200, 225, 250	0000000	000000
2	Bottom	250	2 1/2	Side	13 5/8"	Lever	__	Pop Safety	ASME BPVC.I	15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 125, 150, 175, 200, 225, 250	0000000	000000
Bronze Body—EPR Seal
1/2	Bottom	250	3/4	Side	6 1/2"	Lever	__	Pop Safety	ASME BPVC.I	15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 125, 150, 175, 200, 225, 250	0000000	000000
3/4	Bottom	250	1	Side	7 1/2"	Lever	__	Pop Safety	ASME BPVC.I	15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 125, 150, 175, 200, 225, 250	0000000	000000
1	Bottom	250	1 1/4	Side	8 1/2"	Lever	__	Pop Safety	ASME BPVC.I	15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 125, 150, 175, 200, 225, 250	0000000	000000

ASME-Code Fast-Acting Pressure-Relief Valves for Low-Pressure Steam

For Use With: Steam
Specifications Met: ASME BPVC.IV
Max. Temperature: 250° F

For use with low-pressure steam-heating boilers requiring pressure relief at 15 psi, these valves meet ASME Code Section IV. All spring fully open at the set pressure and remain open until the system pressure is restored below the set pressure. Body is bronze for durability and a long service life.

Vented relief ports exhaust discharge directly.

Threaded relief ports can be attached to a drain line for remote discharge.

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

Straight

Inlet				Relief Port
Pipe Size	Connection	Location	Maximum Pressure, psi	Connection Type	Location	Steam Flow Capacity, lbs./hr.	Set Pressure, psi	Overall Ht.	Test Mechanism	Valve Type		Each
Bronze Body—EPDM Seal
3/4	NPT Male	Bottom	15	Vent	Top	410	15	2 7/8"	Lever	Pop Safety	0000000	000000

Elbow

Inlet				Relief Port
Pipe Size	Connection	Location	Maximum Pressure, psi	Pipe Size	Connection	Location	Steam Flow Capacity, lbs./hr.	Set Pressure, psi	Overall Ht.	Test Mechanism	Valve Type		Each
Bronze Body—PTFE-Coated EPDM Seal
3/4	NPT Male	Bottom	15	3/4	NPT Female	Side	470	15	3 13/16"	Lever	Pop Safety	0000000	000000
1	NPT Male	Bottom	15	1	NPT Female	Side	640	15	4"	Lever	Pop Safety	0000000	00000
1 1/4	NPT Male	Bottom	15	1 1/2	NPT Female	Side	1,200	15	4 1/2"	Lever	Pop Safety	0000000	000000
1 1/2	NPT Male	Bottom	15	2	NPT Female	Side	1,900	15	5 1/4"	Lever	Pop Safety	0000000	000000
2	NPT Male	Bottom	15	2	NPT Female	Side	2,500	15	6 9/16"	Lever	Pop Safety	000000	000000
2 1/2	NPT Male	Bottom	15	2 1/2	NPT Female	Side	3,520	15	8 1/8"	Lever	Pop Safety	000000	000000
3	NPT Male	Bottom	15	3	NPT Female	Side	4,100	15	9 1/16"	Lever	Pop Safety	000000	000000

Fast-Acting Pressure-Relief Valves for Ultra-Low-Pressure Steam

For Use With: Steam
Max. Temperature: 250° F

Choose these valves for small steam-heating boilers requiring pressure relief between 5 psi and 12 psi. They spring fully open at the set pressure and remain open until the system pressure is restored below the set pressure. All have a bronze body for durability and a long service life.

Vented relief ports exhaust discharge directly.

Threaded relief ports can be attached to a drain line for remote discharge.

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

Straight

Inlet			Relief Port
Pipe Size	Connection	Location	Connection Type	Location	Overall Ht.	Test Mechanism	Valve Type	Choose a Set Pressure, psi		Each
Bronze Body—EPDM Seal
3/4	NPT Male	Bottom	Vent	Top	2 7/8"	Lever	Pop Safety	5, 6, 8, 10, 12	0000000	000000

Elbow

Inlet			Relief Port
Pipe Size	Connection	Location	Pipe Size	Connection	Location	Overall Ht.	Test Mechanism	Valve Type	Choose a Set Pressure, psi		Each
Bronze Body—EPDM Seal
3/4	NPT Male	Bottom	3/4	NPT Female	Side	3 13/16"	Lever	Pop Safety	5, 6, 8, 10, 12	0000000	000000
1	NPT Male	Bottom	1	NPT Female	Side	4"	Lever	Pop Safety	5, 6, 8, 10, 12	0000000	00000

Corrosion-Resistant Pressure-Regulating Valves for Steam

For Use With: Steam
Temperature Range: -40° to 450° F

Regulate steam pressure in wet environments and harsh conditions with these valves that have a 316 stainless steel body for exceptional corrosion resistance. They automatically reduce a high, variable inlet pressure to a lower, stable outlet pressure. Adjust the outlet pressure within the range.

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

Inlet			Outlet
Pipe Size	Location	Max. Pressure, psi	Pipe Size	Location	End-to-End Lg.	Choose an Outlet Pressure Range, psi		Each
NPT Female
316 Stainless Steel Body—316 Stainless Steel Diaphragm and PTFE Seal
1/2	Side	400	1/2	Side	4 1/2"	2 to 30, 10 to 50, 30 to 125, 50 to 150	0000000	000000000
3/4	Side	400	3/4	Side	5 1/8"	2 to 20, 10 to 35, 30 to 75, 50 to 110, 105 to 150	0000000	00000000
1	Side	400	1	Side	5 7/8"	2 to 20, 10 to 45, 20 to 60, 55 to 100, 90 to 150	0000000	00000000

Pressure-Regulating Valves for Steam

For Use With: Steam
Temperature Range: -20° to 400° F

Automatically reduce a high, variable inlet pressure in your steam system to a lower, stable outlet pressure. Adjust the outlet pressure within the range. These valves have a cast iron body that absorbs vibration from pressure changes to reduce wear and noise in your pipeline.

Internal strainers trap debris.

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

Valves
Inlet			Outlet						Repair Kits
Pipe Size	Location	Max. Pressure, psi	Pipe Size	Location	End-to-End Lg.	Choose an Outlet Pressure Range, psi		Each		Each
NPT Female
Cast Iron Body—Bronze Diaphragm and 420 Stainless Steel Seal
1/2	Side	250	1/2	Side	3 5/8"	0 to 10, 10 to 50, 40 to 100, 100 to 200	0000000	0000000	0000000	000000
3/4	Side	250	3/4	Side	3 5/8"	0 to 10, 10 to 50, 40 to 100, 100 to 200	0000000	000000	0000000	00000
1	Side	250	1	Side	4 1/2"	0 to 10, 10 to 30, 30 to 50, 40 to 85	0000000	000000	0000000	000000
1 1/4	Side	250	1 1/4	Side	4 1/2"	0 to 10, 10 to 30, 30 to 50, 40 to 85	0000000	000000	0000000	000000
1 1/2	Side	250	1 1/2	Side	6 1/2"	0 to 10, 10 to 30, 30 to 50, 40 to 85	0000000	000000	0000000	000000
2	Side	250	2	Side	6 1/2"	0 to 10, 10 to 30, 30 to 50, 40 to 85	0000000	000000	0000000	000000
Cast Iron Body—Bronze Diaphragm and PTFE Seal with Internal Strainer
1/4	Side	150	1/4	Side	3"	2 to 25, 20 to 60, 30 to 100	0000000	000000	000000	00
3/8	Side	150	3/8	Side	3 7/8"	2 to 30, 20 to 70, 40 to 110, 90 to 150	0000000	000000	000000	00
1/2	Side	150	1/2	Side	4 1/2"	2 to 30, 10 to 50, 30 to 125, 50 to 150	0000000	000000	0000000	000000
3/4	Side	150	3/4	Side	5 1/8"	2 to 20, 10 to 35, 30 to 75, 50 to 110, 105 to 150	0000000	000000	0000000	000000
1	Side	150	1	Side	5 7/8"	2 to 20, 10 to 45, 20 to 60, 55 to 100, 90 to 150	0000000	000000	0000000	000000
1 1/4	Side	150	1 1/4	Side	6 3/4"	2 to 15, 10 to 30, 20 to 50, 45 to 100, 90 to 150	0000000	000000	0000000	000000
1 1/2	Side	150	1 1/2	Side	6 3/4"	2 to 15, 10 to 30, 20 to 50, 45 to 100, 90 to 150	0000000	000000	0000000	000000
2	Side	150	2	Side	9 1/4"	2 to 20, 10 to 60, 20 to 100, 90 to 150	0000000	00000000	0000000	000000

High-Accuracy Pressure-Regulating Valves for Steam

For Use With: Steam
Temperature Range: 40° to 450° F

Control steam line pressure with ±1 psi accuracy. These valves automatically reduce a high, variable inlet pressure to a lower, stable outlet pressure. Adjust the outlet pressure within the range. Valves have a cast iron body that absorbs vibration from pressure changes to reduce wear and noise in your pipeline. They meet ANSI/FCI 70-2 Class IV for tight shut-off (max. leakage rate of 0.01%). Install 1/4 NPT male pipe (not included) between the control valve and your downstream steam line.

Repair kits (sold separately) include replacement seals, diaphragm, spring, and spring assembly.

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

Valves
Inlet			Outlet					Repair Kits
Pipe Size	Location	Max. Pressure, psi	Pipe Size	Location	Choose an Outlet Pressure Range, psi		Each		Each
NPT Female
Cast Iron Body—301 Stainless Steel Diaphragm and 420 Stainless Steel Seal
1/2	Side	250	1/2	Side	3 to 20, 5 to 50, 10 to 100, 20 to 150	0000000	000000000	0000000	0000000
3/4	Side	250	3/4	Side	3 to 20, 5 to 50, 10 to 100, 20 to 150	0000000	00000000	0000000	000000
1	Side	250	1	Side	3 to 20, 5 to 50, 10 to 100, 20 to 150	0000000	00000000	0000000	000000
1 1/4	Side	250	1 1/4	Side	3 to 20, 5 to 50, 10 to 100, 20 to 150	0000000	00000000	0000000	000000
1 1/2	Side	250	1 1/2	Side	3 to 20, 5 to 50, 10 to 100, 20 to 150	0000000	00000000	0000000	000000
2	Side	250	2	Side	3 to 20, 5 to 50, 10 to 100, 20 to 150	0000000	00000000	0000000	00000000

Extended-Life Pressure-Regulating Valves for Steam

For Use With: Steam
Temperature Range: -20° to 400° F

For a longer service life than cast iron valves, these have a durable bronze body. All automatically reduce a high, variable inlet pressure to a lower, stable outlet pressure. Adjust the outlet pressure within the range. Valves have an internal strainer to trap debris.

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

Inlet			Outlet
Pipe Size	Location	Max. Pressure, psi	Pipe Size	Location	End-to-End Lg.	Choose an Outlet Pressure Range, psi		Each
NPT Female
Bronze Body—Bronze Diaphragm and PTFE Seal
1/4	Side	250	1/4	Side	3"	2 to 25, 20 to 60	00000000	0000000
3/8	Side	250	3/8	Side	3 7/8"	2 to 30, 20 to 70, 40 to 110, 90 to 150	00000000	000000
1/2	Side	250	1/2	Side	4 1/2"	10 to 50, 2 to 30, 30 to 125, 50 to 150	00000000	000000
3/4	Side	250	3/4	Side	5 1/8"	10 to 35, 105 to 150, 2 to 20, 30 to 75, 50 to 110	00000000	000000
1	Side	250	1	Side	5 7/8"	10 to 45, 2 to 20, 20 to 60, 55 to 100, 90 to 150	00000000	000000
1 1/4	Side	250	1 1/4	Side	6 3/4"	10 to 30, 2 to 15, 20 to 50, 45 to 100, 90 to 150	00000000	00000000
1 1/2	Side	250	1 1/2	Side	6 3/4"	10 to 30, 2 to 15, 20 to 50, 45 to 100, 90 to 150	00000000	00000000
2	Side	250	2	Side	9 1/4"	10 to 60, 2 to 20, 20 to 100, 90 to 150	00000000	00000000

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About Pressure-Relief Valves

ASME-Code Fast-Acting Pressure-Relief Valves for Steam

ASME-Code Fast-Acting Pressure-Relief Valves for Low-Pressure Steam

Fast-Acting Pressure-Relief Valves for Ultra-Low-Pressure Steam

Corrosion-Resistant Pressure-Regulating Valves for Steam

Pressure-Regulating Valves for Steam

High-Accuracy Pressure-Regulating Valves for Steam

Extended-Life Pressure-Regulating Valves for Steam