Kunkle Valves

We stock most Kunkle safety and relief valve lines and source the rest. Send us the part number and we’ll confirm availability and lead time with your quote. Requests received before 3 PM ET are typically quoted the same business day.

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Select a product series to explore models, sizes, and configurations.

Kunkle 189/363/389

Kunkle 189, 363 and 389 are heavy duty safety valves for cryogenic and liquefied air, oxygen and gas service — multi-stage air and gas compressors, intercoolers, aftercoolers and receivers, thermal expansion relief, and full rated capacity discharge on air, gas and liquefied gas lines. All three share a −320°F to 350°F range, FNPT connections in ½" or ¾" inlet with a ¾" outlet, a three-piece disc assembly with a PTFE seat and seal, and a control ring for precise blowdown adjustment. Choose by pressure and material: the 363 is bronze, 50 to 1,000 psig; the 189 is bronze, 1,000 to 2,500 psig; the 389 is all stainless steel and spans the full 50 to 2,500 psig. Relieving capacity runs 38 to 1,506 SCFM of air depending on set pressure. ASME Sections VIII and XIII with the 'UV' designator, National Board certified. Each model is available with a plain lift lever, a pressure-tight threaded cap for gas service only, or a packed lift lever — except the 389, which has no plain lever version.

3 models View series →

Kunkle 215V

Cast iron vacuum relief valves protecting high volume vacuum pumps, conveying systems and light gauge tanks. Sizes 2", 2-1/2" and 3", set from 2 to 29 in. Hg, relieving up to 936 SCFM. Non-code, PED certified — vacuum service only, not suitable for positive pressure.

3 variants View series →

Kunkle 264/265/266/267

Extra heavy relief valves for pumps, compressors, pressure vessels and systems handling corrosive fluids or vapors at high pressure and temperature. Carbon steel with 316 stainless trim (264, 265) or all 316 stainless (266, 267), covering -320°F to 750°F. Single 0.110 in² orifice, set from 4 to 3,300 psig. ASME Section VIII and XIII 'UV' and National Board certified for air/gas and steam; liquid relief is non-code. Also suitable for sentinel warning service on steam equipment.

4 models View series →

Kunkle 300/600

Cast steel, flanged, exposed spring safety valves with stainless steel full-nozzle trim, for steam boilers and generators, pressure reducing stations, air and gas compressors and pressure vessels. Ten orifices from F to Q, 0.307 to 11.045 in², -20°F to 800°F. Model 300 has a 300# inlet flange and is set to 740 psig; Model 600 has a 600# inlet flange and is set to 1,000 psig. ASME Section I 'V' and Section VIII/XIII 'UV', National Board certified.

2 models View series →

Kunkle 337

Cast iron ASME Section VIII and XIII 'UV' safety valves for low to medium pressure blowers, compressors, conveying systems and bulk hauling equipment. Sizes 2", 2-1/2" and 3", set from 1 to 60 psig, relieving up to 5,136 SCFM of air.

3 variants View series →

Kunkle 40R

All stainless steel sentinel warning valves for non-code steam service on steam equipment, including steam turbines. 1/2" and 3/4" male NPT, 1 to 400 psig, -60°F to 850°F, top discharge. Warning devices only — a sentinel valve signals overpressure, it does not relieve it, and it is not a substitute for a code safety valve.

2 variants View series →

Kunkle 40RL

The Model 40R fitted with a plain lift lever. All stainless steel sentinel warning valves for non-code steam service, 1/2" and 3/4" male NPT, 1 to 400 psig, -60°F to 850°F. Warning devices only — a sentinel valve signals overpressure, it does not relieve it, and it is not a substitute for a code safety valve.

2 variants View series →

Kunkle 537

Bronze and cast iron safety relief valves for low pressure hot water boilers, heat exchangers and generators. Four sizes from 3/4" x 1" to 2" x 2-1/2" FNPT, set from 15 to 160 psig, relieving up to 24,871 lb/h (24.9 million BTU/h). ASME Sections IV and XIII 'HV', National Board certified. Bronze body on 3/4" and 1"; cast iron on 1-1/2" and 2".

4 variants View series →

Kunkle 541/542/548

Compact brass air and gas safety valves for compressors, intercoolers, aftercoolers, instrument and control air lines and air receivers. 1/4" and 1/2" male NPT, 3 to 400 psig depending on model, with a manual lift ring and factory seal. The three models differ by seat: Buna-N on the 541, Viton on the 542 for higher temperatures, and a stainless steel ball seat on the 548 for the widest range at -60°F to 400°F. ASME Section VIII and XIII 'UV', National Board certified at 15 psig and above.

3 models View series →

Kunkle 6000 Series

Full-nozzle bronze safety relief valves for steam boilers and generators, air and gas compressors, intercoolers and pressure vessels. Threaded NPT, 1/2" to 2-1/2", 3 to 300 psig, -60°F to 425°F. Metal, EPR, Viton and PFA seat options across ASME Sections I, IV, VIII and XIII.

9 models View series →

Kunkle 6200 Series

Cast iron safety valves for steam boilers and generators, pressure reducing stations, air and gas compressors and pressure vessels. Orifices J through R, 1-1/2" to 6" inlet, 10 to 250 psig, -20°F to 406°F. Model 6252 is ASME Section I and Section VIII; model 6254 is Section IV at 15 psig. Not for lethal or flammable service.

2 models View series →

Kunkle 71S/171/171P/171S

Kunkle 71S, 171, 171P and 171S are extra-heavy, rugged non-code liquid relief valves for overpressure relief, pressure regulation, by-pass relief and the protection of pumps, tanks, lines and hydraulic systems carrying acid, caustic, ammonia and other corrosive liquids. All four share the same design — lapped seats, a spherical pivot between disc and spring to correct misalignment, stainless steel springs — and differ only in body material and lever type. FNPT connections from 1/2" through 2", relieving 1 to 374 GPM at 25% accumulation depending on size. Choose by material and service temperature: 71S cast iron, to 250 psig and 406°F; 171 carbon steel, to 400 psig and 550°F; 171P the same as the 171 with a packed lift lever; 171S all 316 stainless including the spring. These valves carry no ASME stamp and no National Board certification — they are not code valves. Maximum back pressure is 50 psig, and back pressure increases set pressure on a one-to-one basis while reducing capacity.

4 models View series →

Kunkle 900 Series

Bronze, carbon steel and stainless steel safety relief valves for air and gas compressors, liquid-filled vessels and systems, high temperature hot water boilers, steam service and vacuum. Orifices D through J, 3 to 1,400 psig, -320°F to 800°F. Metal and resilient seats, ASME Sections I, VIII and XIII.

13 models View series →

Kunkle 930

Cast iron safety valves for low pressure steam heating boilers, fixed at 15 psig set pressure. Threaded NPT, 2", 2-1/2" and 3" with matching inlet and outlet, relieving 3,164 to 6,949 lb/h of steam. ASME Sections IV and XIII 'HV', National Board certified.

3 variants View series →

Kunkle Liquid Relief Valves

Extra-heavy bronze liquid relief valves for overpressure protection of pumps, tanks, lines and hydraulic systems, and for pressure regulation and continuous by-pass relief. Eight models, threaded NPT, 1/2" to 3", 1 to 500 psig, -60°F to 406°F. Non-code — no ASME stamp and no National Board certification.

8 models View series →

Kunkle Model 1

Kunkle Model 1 brass safety valves discharge from the top and have no outlet connection at all — the companion Model 2 is the side-outlet version of the same valve. Available with ½", ¾" or 1" male NPT inlets for air, non-hazardous gas and steam service: portable and stationary compressors, receivers, tanks, intercoolers and aftercoolers, steam turbines, kettles and other steam-processing equipment. 5 to 250 psig, −60°F to 406°F, ASME Sections VIII and XIII with the 'UV' designator and National Board certified. Air capacity runs 27 to 370 SCFM and steam 84 to 1,039 lb/h depending on inlet size. Note that valves set below 15 psig carry no code stamp and no 'NB' marking on the nameplate, although the capacity tables start at 5 psig. Kunkle also names Model 1 as suitable for sentinel (warning) service on steam equipment — see the Model 40R/40RL datasheet.

6 variants View series →

Kunkle Model 2

Kunkle Model 2 brass safety valves discharge through a side outlet — ¾" FNPT on the ½" and ¾" sizes, 1" FNPT on the 1" — where the companion Model 1 discharges from the top with no outlet connection. Available with ½", ¾" or 1" male NPT inlets for air, non-hazardous gas and steam service: portable and stationary compressors, receivers, tanks, intercoolers and aftercoolers, steam turbines, kettles and other steam-processing equipment. 5 to 250 psig, −60°F to 406°F, ASME Sections VIII and XIII with the 'UV' designator and National Board certified. Air capacity runs 27 to 370 SCFM and steam 84 to 1,039 lb/h depending on inlet size. Note that valves set below 15 psig carry no code stamp and no 'NB' marking on the nameplate, although the capacity tables start at 5 psig.

6 variants View series →

Don’t see your Kunkle model?

The models above are the ones we’ve built out so far. We source the full Kunkle line — send us the model and size off the nameplate and we’ll quote it. Requests received before 3 PM ET are typically quoted the same business day.

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Commonly requested models we source but haven’t listed yet: 30 · 91 · 140 · 218 · 228 · 230 · 299 · 330 · 338 · 803 · 818