13 best relief valves
A relief valve is a critical component in various industrial, scientific, and mechanical systems, particularly those involving fluid or gas pressure control. It serves the important function of protecting equipment and systems from excessive pressure, which can lead to damage or catastrophic failure. Relief valves are commonly used in applications related to valves, fittings, hydraulics, pneumatics, plumbing, and various industrial processes.
Here are some key points about relief valves:
Purpose: Relief valves are designed to relieve excess pressure in a system by diverting the fluid or gas to a safe outlet. They prevent the pressure from exceeding a predetermined set point, ensuring that equipment and components remain within their specified operating limits.
Types: There are different types of relief valves, including:
Pressure Relief Valves: These are the most common type and open to release pressure when it surpasses the set limit.
Safety Relief Valves: Often used in high-pressure and critical systems, safety relief valves provide an extra level of protection and are designed to meet stringent safety standards.
Pilot-Operated Relief Valves: These valves use a pilot valve to control the opening and closing of the relief valve, offering precise pressure control.
Vacuum Relief Valves: Designed to prevent a vacuum from forming in a system, these valves open to allow air into the system when pressure drops too low.
Applications: Relief valves are found in a wide range of applications, including hydraulic systems, pneumatic systems, steam boilers, pressure vessels, pipelines, and industrial processing equipment. They are critical for maintaining system safety and preventing overpressure-related accidents.
Operating Principle: Relief valves operate based on the principle of balancing forces. When the pressure exceeds the set point, the force generated by the pressure acting on the valve's internal components overcomes the force exerted by a spring or other mechanism, causing the valve to open and release the excess pressure.
Set Pressure: The set pressure of a relief valve is carefully calibrated to match the maximum allowable pressure for the system it protects. Properly setting and periodically testing relief valves is essential for their effectiveness.
Maintenance: Regular maintenance and inspection of relief valves are crucial to ensure their proper functioning. This includes checking for leaks, corrosion, and ensuring that the valve's set pressure remains accurate.
Codes and Standards: Relief valves are subject to industry-specific codes and standards that dictate their design, installation, and maintenance requirements. Compliance with these standards is essential for system safety.
Emergency Situations: In emergency situations where pressure cannot be controlled by other means, relief valves provide a last line of defense to prevent catastrophic failures.
In summary, relief valves are vital components in various industries and applications, playing a crucial role in maintaining system safety by preventing overpressure.Proper selection, installation, and maintenance of relief valves are essential to ensure they perform their intended function effectively.
Below you can find our editor's choice of the best relief valves on the market
Rheem SP12574 Temperature and Pressure Relief Valve,Small
Rheem
Product description
Rheem SP12574 Temperature and Pressure Relief Valve,Small
From the Manufacturer
Rheem is a leading provider of gas furnaces, heat pumps, air conditioners, air handlers, indoor air quality products, gas and electric water heaters.
- For best results, use only Rheem replacement parts for repairing your Rheem Water Heater
- Maximum Temperature Setting (Deg. F): 210, Maximum Pressure Setting (psi): 150, CSA Capacity (BTU/HR): 105,000, Inlet Thread Size - NPT (in.): 3/4
- Outlet Thread Size - NPT (in.): 3/4, Overall Length (in.): 7-1/4, Body Length (in.): 3-1/4, Sensor Length (in.): 4
- Kits which contain this part: 45W613
User questions & answers
| Question: | Is this one good for Model 21DV50? Thanks |
| Answer: | Fit my Richmond. Pretty generic part. |
| Question: | can this be used as a side instead of on top PRV |
| Answer: | You want to look for, and match, three things on the new valve; Pressure rating in PSI, Pipe thread pitch, and tempurature (not as important, but still something to note). This valve- Maximum Temperature Setting (Deg. F): 210, Maximum Pressure Setting (psi): 150 You want to match the specifications that you have on the water heater information plate, just in case you had the wrong pressure on the previous valve. It'll probably say something like: Maximum pressure: 300 PSI Working Pressure: 150 PSI -which means that you want it to match the 150 PSI Temp is something to pay attention to, but if you can't find the specs on the water heater, it's probably fine to just go with what was on the previous valve. This particular valve is pretty standard, and will probably fit most regular water heaters in the US (at least, my last water heater, and my current one both have the same size pipe thread, if I recall correctly). If you're not sure, and you want to be positive, you can probably just remove the old valve (after watching a how-to vid online) and take it to a hardware store, or plumbing shop. Alternatively, you can research the model of water heater you have online and probably find out the answers to all necessary specs. |
| Question: | Will this fit richmond model 5V |
| Answer: | The kit includes everything you need to test yourself. It also comes with a pre-paid envelope to send in the test if you find mold. |
| Question: | How do i know the right Pressure relief vale to buy |
| Answer: | It takes a bit if you didn’t pay the extra to have it done right away. My answers came by email. |
Camco 10423 1/2" Temperature and Pressure Relief Valve with 4" Epoxy-Coated Probe
Unknown
Product description
Camco’s 1/2" Temperature and Pressure Valve with 4" Probe will help protect your RV water heater from excessive temperature and water pressure. It's factory set at 150 PSI and crafted with no gaskets and an epoxy-coated probe to prevent corrosion buildup.
From the Manufacturer
The Camco 1/2-Inch temperature and pressure relief valve with 4-Inch probe protects the RV water heater from excessive temperature and water pressure with corrosion-resistant metal. This valve is set at 150 PSI and is crafted with epoxy-coated probes to prevent corrosion buildup.
- Protects water heaters from excessive water temperatures and pressure
- Resistant to corrosion
- Factory preset to 150 psi and 210 degrees Fahrenheit
- 1/2" - 14 NPT male inlet; 1/2" - 14 NPT female outlet with 4" probe
- CSA certified
User questions & answers
| Question: | What is the outlet size ? Also |
| Answer: | The insert end (probe end) has 1/2" threads, the other 3/4" NPT. |
| Question: | Is this Camco 10423 "Made in USA"? Is similar Atwood 91604 "Made in USA |
| Answer: | Mary, I can tell you these are for motorhome and trailer water heaters. It a 195 degree valve with 1/2 threads. There is a tag on your old valve and it will tell you size and temp. |
| Question: | does this fit sw6del water heater 1/2 " or |
| Answer: | 3/4 NPT inlet 90° to a 3/4 NPT outlet. |
| Question: | I have an american standard water heater model asdv-6r, serial e0a-0389. will this valve fit it |
| Answer: | I would say yes as this reacts to pressure and or temperature. |
Control Devices - CR25-100 -CR25 CR Series Brass Pressure Relief Valve, 0-100 psi Adjustable Pressure Range, 1/4" Male NPT
Control Devices
Product description
- Relief pressure adjustable from 0 to 100 psi
- 1/4" male NPT threaded inlet connection
- Brass construction and stainless steel spring for corrosion resistance
- Silicon O-ring provides leak-proof seal to within 10 percent of set pressure
- Micrometer-style nylon knob for pressure relief adjustment
User questions & answers
| Question: | Is the reseat pressure adjustable on this as well, I'm needing it to crack at 100psi and reseat at 85-90psi, No lower. other don't reseat till 60psi |
| Answer: | Not great I think you better off getting something with narrower range device like 0-10 psi |
| Question: | Anyone had issues where it vents no matter what the pressure is set at? I'm testing it for a spunding valve with an inlet pressure of 15psi |
| Answer: | Reseating is not an issue for me, but setting a reasonably accurate and consistent pressure is a problem. The release pressure varies significantly (when used as a pressure relief valve for tyre inflation). |
| Question: | How does this work in the 2-4 PSI range |
| Answer: | The outlet is 1/2". |
| Question: | Anyone else have the problem where it releases all the pressure instead of resealing |
| Answer: | I have had this in my motor home for more than two years now and it works just great. But sorry, I am not sure where it was made as I have lost all my information on this item. The motor home is not handy right now are I would go out and see if their is any information visible on it. Camco Manufacturing is a North Carolina business however and is listed as the top 100 private companies in North Carolina. |
Watts Brass & Tubular 374A 3/4 Boiler Relief Valve
Watts Brass & Tubular
Product description
WATTS BRASS & TUBULAR 374A 3/4 Boiler Relief Valve
- Protects hot water space heating boilers Compact construction, produces exceptionally high capacity Protects boiler installations up to 550,000 Btu/hr at 30 lb
- This product adds a great value
- This product is manufactured in United States
User questions & answers
| Question: | Can this valve replace a model number 174a? Can it be set at 60 lbs |
| Answer: | Yes it is Model M |
| Question: | is the model M |
| Answer: | The reseat is not adjustable. It will reseat on its on around those pressures but it is not a controllable parameter. |
| Question: | is the model M |
| Answer: | No issues here, also spunding valve. Are you sure it's not leaking at the thread? |
Legend Valve 111-303NL T-50 No Lead Pressure Relief Valve 100-150 PSI, 1/2"
Legend Valve
Product description
LEGEND MODEL T-50 pressure relief valves are for protection against excessive pressure. Recommended for all water system installations to protect against damage to piping and pressure tanks. They are set at 100 P.S.I. and are adjustable to 150 P.S.I.
User questions & answers
| Question: | Is this lead free |
| Answer: | Channel locks |
| Question: | How do you adjust the max PSI |
| Answer: | I don’t know, but you may want to get something that is set a little closer to the 60 psi that you need like a 174a-050. Good luck on your search. |
| Question: | How do you remove the knurled cap |
| Answer: | Yes |
Camco 10471/10473 3/4" Temperature and Pressure Relief Valve with 4" Epoxy-Coated Probe
Unknown
Product description
Camco’s 3/4" Temperature and Pressure Valve with 4" Probe will help protect your RV or home water heater from excessive temperature and water pressure. It's factory set at 150 PSI and 210F. It features epoxy-coated probe to prevent corrosion buildup.
- 3/4" NPT connection
- Factory set at 150 PSI and 210F
- 4" probe
- Brass body with stainless spring
- Listed to ANSI Z21.22
User questions & answers
| Question: | Does this come in a female connector |
| Answer: | Camco 10471/10473 3/4" NPT connection Factory set at 150 PSI. I am not familiar with Raritan WH3, the product details read as follows. Committed to the environment and preserving sea life, Raritan designs products to help maintain an environmental balance and ensure the quality of marine waters. I cannot guarantee the Camco product follows these environmental guidelines. The Raritan product is rated at 75 PSI. I would not recommend substituting this item. |
| Question: | Does this valve open only at 150psi, or does it start to open at 75psi |
| Answer: | The heat generated is not as important as the pressure. I believe the max pressure of this valve is 150 PSI. I seem to recall that the working pressure in the Dometic water heater is around 125 PSI. |
| Question: | Is this the same valve as the Raritan WH3 or can it be substituted to it |
| Answer: | Yes, the "NL" at the end of the part number is the Legend designation for no lead. |
| Question: | need something to relieve at least 165,000 btu. where do I find this |
| Answer: | AN ADJUSTMENT SCREW UNDER THE CAP |
Control Devices-ST25-1A ST Series Brass ASME Safety Valve, 125 psi Set Pressure, 1/4" Male NPT
Control Devices
Product description
- Relief pressure preset to 125 psi with flow rate of 116 cfm
- 1/4" male NPT threaded inlet connection
- Brass construction and stainless steel spring for corrosion resistance
- 250 degrees F maximum temperature for use in high temperature applications
- ASME safety rated with UV and NB marks
User questions & answers
| Question: | Mine blows out at less than 60 lbs, anybody else have this problem |
| Answer: | My small compressors is also rated for 125 psi control relief valve. I have a 100psi on one compessor in my work shop and a 125psi in the garage compressor. You also have to understand that when you start the compressor, note: at what pressure does the regulator shut down the compressor. You don't want a lower psi relief valve lesser than what the air compressor shuts off at. The relief valve would be relieving all the time. Also, safety, you don't want the tank to rupture with a higher psi relief valve of what is rated for the tank. Good luck! Note: Be sure and get the right Size and thread size 1/4" or 1/2". |
| Question: | Does the red stuff on the threads replace pipe dope or do I still need to use it? what do I do to the red stuff? It appears to be hard |
| Answer: | Male only I believe. |
| Question: | I have hitachi ec 12, 4 gallon max pressure 125 psi,3.6 cfm @ 100 psi what size pressure relief valve do i need to get to replace the broken one |
| Answer: | We are not sure. It says factory set at 150psi but If you look on the questions asked there is an 800 number it says you can call with any questions. |
Legend Valve 111-302NL T-50 No Lead Pressure Relief Valve 75-150 PSI, 1/2"
Legend Valve
Product description
LEGEND MODEL T-50 pressure relief valves are for protection against excessive pressure. Recommended for all water system installations to protect against damage to piping and pressure tanks. They are set at 75 P.S.I. and are adjustable to 150 P.S.I.
Adjustment procedure:
1. Remove knurled access cap (Part #1)
2. Mark the position of the screwdriver slot in the disc (Part #3), in
relation to the body (Part #8); Using a permanent marker, make a
reference mark on the top edge of the body, at either end of the slot.
3. With a large flat-blade screwdriver, turn the disc clockwise to
INCREASE the relief pressure. One complete 360° revolution equates
to a 25 p.s.i. increase: 75 p.s.i. factory setting plus three complete
revolutions from the reference mark attains the 150 p.s.i. setting. 100
p.s.i. factory setting plus two complete revolutions from the reference
mark attains the 150 p.s.i. setting.
4. Replace the knurled cap. Do not over-tighten.
User questions & answers
| Question: | When product arrived, it had a sticker on it advising about possible cancer or impotence. yet this product is advertised to be lead free. why warning |
| Answer: | Mfr's instructions here: http://www.legendvalve.com/images/specsheets/20121115-T50-134030.pdfAdjustable from 75 to 150 p.s.iFactory-set at 75 p.s.iAdjustment procedure:1. Remove knurled cap2. With a flat-blade screwdriver, turn the adjustment discclockwise to increase relief pressure, or counter-clockwiseto decrease relief pressure.One 360-degree clockwise turn equates to a 25 p.s.i increase.Therefore, three complete revolutions attains the 150 p.s.i setting. |
| Question: | Can I use this on my cold water line for a water heater |
| Answer: | 1/2” male threads on one side and 1/2” female threads on other side |
| Question: | How is this valve adjusted? I just installed mine and I have a steady drip from the discharge line. I currently have between 45-55 psi |
| Answer: | no problems, cut off set at 125 psi |
| Question: | Is this 1/2 inch to |
| Answer: | Leave the red the stuff on threads |
Watts 0342691 30 PSI Pressure Relief Valve, Bronze, 3/4" 335 M2-030
Watts
Product description
Watts 3/4 in. FNPT Brass Pressure Relief Valve FNPT
- Female pressure relief valve
- Inlet (in): 3/4
- Outlet (in): 3/4
- BTU: 510,000
- Inlet (in): 3/4
- Outlet (in): 3/4
- Pressure (psi): 30
User questions & answers
| Question: | Does this automatically reset? If pressure falls back below 30psi, will the valve close itself again |
| Answer: | I assume you mean boiler? Yes, I used it on my gas boiler wo problems. Just shut the water feed bleed the pressure and let the water cool or you will get sprayed w hot water when you change the valve! |
| Question: | What’s the max operating temperature |
| Answer: | It's more then less the same thing both are for water system 30 psi so I think it's replaceable with that one. |
| Question: | will it work with gas furnace |
| Answer: | That’s is there for California. The lead free law specifies lead under a certain amount, essentially lead free but there is a trace. So CA still requires the warning On any cast brass sold there. The manufacturers label them all that way. |
| Question: | What'' the difference between this and the Watts 374A model besides price |
| Answer: | You can install it on the cold line supplying the water heater As a pressure relief valve for the water system, BUT your water heater still needs a “temperature” & pressure (T&P) relief valve. |
Control Devices-ST25-1A ST Series Brass ASME Safety Valve, 60 psi Set Pressure, 1/4" Male NPT
Control Devices
Product description
- Relief pressure preset to 60 psi with flow rate of 61 cfm
- 1/4" male NPT threaded inlet connection
- Brass construction and stainless steel spring for corrosion resistance
- 250 degrees F maximum temperature for use in high temperature applications
- ASME safety rated with UV and NB marks
User questions & answers
| Question: | How do I adjust the set pressure on this? It's popping off at @ 43 psi |
| Answer: | Technically there are many parts to this valve. There's the set screw, the spring, the body, the blowdown adjustment ring, a seat disc, the nozzle. All of which comprise one safety relief valve. so if your question is if this is the price for one valve, then yes, it's just one, but it comes as one complete valve with many things. |
| Question: | Can this replace the regulator safety pressure relief - 60 psi - chudnow |
| Answer: | I think so. About 3 years ago, I replaced an old valve in the hydraulic heating system and this works fine so far. This relief valve keeps the maximum water pressure at 30 psi. |
| Question: | is this price for one thing |
| Answer: | 250 F |
ZURN WILKINS 34-P1500XL 2471325 P1500 Calibrated Pressure Relief Valve, 25 To 175 Psi, 3/4" Mnpt x 3/4" Fnpt, Lead Free
Zurn Wilkins
Product description
Wilkins P1500 calibrated pressure relief valve, 25 to 175 psi, 3/4 in. Mnpt x 3/4 in. Fnpt, lead free. Vacuum relief valve: Vr10. The product is manufactured in United States.
- Wilkins P1500 calibrated pressure relief valve, 25 to 175 psi, 3/4 in. Mnpt x 3/4 in. FNPT, Lead free
- Vacuum relief valve: Vr10
- The product is manufactured in United states
User questions & answers
| Question: | What happens if it fails? Using it on a lake irrigation system. If it fails does all the water shoot out of the valve? Don't want excess pressure |
| Answer: | No, a safety valve is not a replacement for a regulator. |
Cash Acme 18821 0150 Temperature and Pressure Relief Valve NCLX-5L, 3/4 in, Brass
Cash Acme
Product description
Cash Acme NCLX Combination Temperature and Pressure Relief Valves are designed for the protection of water heaters and storage tanks. Our NCLX Valves come with standard factory settings of 150 psi for pressure relief and 210 degrees F for temperature relief. Featuring a cast bronze body, brass and stainless-steel internal parts, silicone seat disc and stainless steel pressure spring.
- DESIGN: The NCLX Series relief valves feature a cast bronze body, brass, and stainless steel internal parts, silicone seat disc, and stainless steel pressure spring
- BRONZE BODY: Lead-free and superior reliability
- COMPACT: Pressure reducing and regulating valves
- CERTIFIED: To ASSE standard 1003 and CSA Standard B356; Certified lead free complying with NSF 372
- ASSEMBLED AND TESTED: Prepared in Cash Acme manufacturing plant in Cullman, Alabama
User questions & answers
| Question: | Can i use nclx-5l to replace my old cash acme nclx-5s valve |
| Answer: | Hello, you will need to contact Bradford White and see what size temperature and pressure valve you will need, as well as the BTU rating they require, and length of the temperature probe. These are the specs for this item: 3/4", 500,000 BTU/hr ASME rating, temperature probe is 2-1/8". If their requirements meet the aforementioned specs, then you can use this valve. |
| Question: | Are the nclx-5 and 5l interchangable for side entry |
| Answer: | Hello, Cash Acme part # 18821-0150 has a relief pressure of 150 psi. If you have additional questions please don't hesitate to reach out to our technical support department at 877-700-4242. Best Regards, |
| Question: | Will this fit my Bradford White Defender |
| Answer: | I’m not sure how it would fail other than possibly sticking open or closed. Granted, mine does leak a little around the adjuster. To have a failure like what you’re describing, something catastrophic would have to happen. |
| Question: | What is the psi on this tp |
| Answer: | These valves are not adjustable, if it is not functioning correctly it should be replaced with a new valve. |
Control Devices - ST25-1A200 ST Series Brass ASME Safety Valve, 200 psi Set Pressure, 1/4" Male NPT
Control Devices
Product description
- Relief pressure preset to 200 psi with flow rate of 178 cfm
- 1/4" male NPT threaded inlet connection
- Brass construction and stainless steel spring for corrosion resistance
- 250 degrees F maximum temperature for use in high temperature applications
- ASME safety rated with UV and NB marks
User questions & answers
| Question: | Does it release right at 200psi because I have a 200psi pressure switch |
| Answer: | Hello, Cash Acme T&P relief valves NCLX-5L and NCLX-5S have the same BTU/hr capacity when set at the same 150 psi set pressure. That being said, the element and shank length for these two valves are different and it will be necessary to contact the water heater's manufacturer to check for compatibility with your particular model of water heater. There is a link to the spec sheet for these products below that has dimensional information. If you have additional questions please don't hesitate to reach out to our technical support department at 877-700-4242. https://www.cashacme.com/wp-content/uploads/2014/08/NCLX_Spec.pdf Best Regards, |
| Question: | can this relief valve be used to drain water from the air tank |
| Answer: | Hello, Cash Acme models NCLX-5 and NCLX-5L (3/4"/150 PSI) have the same CSA and ASME relief capacities (105,000/500,000). That being said, it will be necessary to contact your water heater's manufacturer to see if the dimensions of these valves are compatible with your particular model. It is important that the valve's relief capacity, shank length, element length, size and pressure setting are correct for the your particular model water heater. There is a link below to the spec sheet for these valves. If you have additional questions please don't hesitate to reach out to our technical support department at 877-700-4242. https://www.cashacme.com/wp-content/uploads/2014/08/NCLX_Spec.pdf Best Regards, |
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