Can we reduce the number of vendors required to service all of our valves?

Yes! By selecting a company that has technicians trained in all different types of valve repair, you can save money on repairs, as well as on mobilization charges.

Allied Valve’s technicians are trained to repair all types of valves from all manufacturers. Our six locations are strategically placed to help you save money by reducing technician travel time.

Learn more about our valve repair services.


Can a safety valve be reset on site?

Yes, but the valve will not carry the VR code certification unless it is disassembled and inspected. In some cases, the valve may require a new spring and spring washers before it can be reset.

Can a valve be swapped to another unit if the set pressure is the same, but the media is different?

That depends on the situation:

  • A Section VIII coded valve cannot be used for any Section I application.
  • A Section I coded steam valve can be used on Section VIII steam applications.
  • All other valves under Section VIII can be reset for the medias within Section VIII if the valve design allows.

What is your standard turnaround time on PRV and line valve repairs?

Our standard turnaround for valve repairs is 2 weeks. But, we can also accommodate same-day or next-day repair service. Contact us to learn more about our pressure relief valve and line valve repair services.

What information do I need to properly size and select a valve?

Six basic pieces of information are required to size and select a safety or pressure relief valve:

  1. Connection size and type
  2. Set pressure (psig)
  3. Temperature
  4. Back pressure
  5. Service
  6. Required capacity

More information: How to select and size safety valves and pressure relief valves

What is the blowdown of a Section VIII or non-code safety valve?

The ASME Boiler and Pressure Vessel Code does not have blowdown requirements for Section VIII (or non-code) valves. Blowdown may vary from less than 2% to more than 50%, depending on many factors including: valve design, dimensional tolerance variation, where the set pressure falls in the set pressure range of a spring, spring rate/force ratio, warn ring/guide settings, etc. Typical blowdown for most valves is 15% to 30%, but cannot be guaranteed.

How does back pressure affect valve set pressure and capacity?

Back pressure reduces set pressure on a one to one basis, i.e., a valve set at 100 psig subjected to a back pressure at the outlet of 10 psig will not actuate until system pressure reaches 110 psig.

Back pressure drastically reduces capacity. Typically backpressure of 10% of set pressure will decrease capacity by 50%. Specific capacity reduction should be determined by the user on a case by case basis by flow testing. Back pressure in excess of 10% of set pressure is not recommended.

Learn more about how back pressure affects valve operation.

Under what conditions may the lift lever or lifting device be omitted on Section VIII valves?

Section VIII UG-136(a)(3) states “Each pressure relief valve on air, water over 140o F (60o C), or steam service shall have a substantial lifting device which when activated will release the seating force on the disk when the pressure relief valve is subjected to a pressure of at least 75% of the set pressure of the valve.”

Code Case 2203 states the lifting device may be omitted provided:

  1. The user has a documented procedure and an associated implementation program for the periodic removal of the pressure relief valves for inspection and testing, and repair as necessary.
  2. The omission is specified by the user.
  3. The user shall obtain permission to omit the lifting device from the authority having jurisdiction over the installation of pressure vessels.

Does altitude affect set pressure?

No. Gage pressure (psig) is used to set valves so the effects of weather and altitude on set pressure can be ignored.

Can I use a Section I steam valve in a Section VIII steam application?

Yes. Section I valves have more stringent setting blowdown requirements and may be used in Section VIII steam applications since they meet all the requirements as specified in Section VIII UG-125(a) “Pressure Relief Devices,” which states pressure relief devices must be “in accordance with the requirements of UG-125 through UG-137.” In addition, UG-125(b) specifies that even unfired steam boilers MUST use a Section I pressure relief device.

Why does my valve actuate/open early?

Valves often appear to actuate early, even when they aren’t. Safety and pressure relief valves may “simmer,” or “warn” at 80 to 90% of the set pressure, but this is not the same as a full open.

More information: Why is my valve opening early?

How high can my system pressure be before my valve opens?

A minimum operating gap of 10% between the system operating pressure and the safety valve’s nameplate set pressure should be maintained. Since direct spring-operated safety valves may “simmer” or “warn” at 90% of the nameplate set pressure, and since the factory standard leak test is performed at 80% of nameplate set pressure, better seat tightness performance can be expected with an operating gap of 20%.

Why is my valve leaking?

Valve leakage is a common occurrence in industrial settings. Even valves labeled as “zero leakage,” or “bubble tight,” are not necessarily completely leakage-free.

Read our article “Why is my valve leaking?” to learn more about the types of valve leakage, common causes of valve leakage, industry standards, and what you can do to prevent damage caused by valve leakage.

More information: Valve leakage tests explained

What set pressure should the valve be set to open?

Typically, the valve should be nameplate set to open at the MAWP (Maximum Allowable Working Pressure) of the vessel the valve is intended to protect. There is a tolerance to actual set pressure, which means a valve set at 100 psig nameplate may open slightly above or below 100 psig. Consult the current ASME Boiler and Pressure Vessel Code for tolerance classes and special situations when the set pressure may be different than the MAWP.

Which end should be connected for vacuum valves?

This is a confusing topic because the correct installation often looks backward. A paper instruction tag illustrating the proper connection is attached to each valve. Vacuum valves should have the NPT threads that are cast integral to the body attached to the vacuum source. See the assembly drawing for additional clarification.

Why is there a hole in the valve body?

This drain hole is required on some models by the ASME Boiler and Pressure Vessel Code. It is intended to prevent any condensate from accumulating in the body that may freeze or corrode internal valve parts and prevent the valve from opening. The drain hole should be piped away to safely dispose of any discharge or condensate.

What mounting orientation should be used to install a safety valve?

Installing a safety valve in any position other than with the spindle vertical and upright may adversely affect performance and lifetime.

Section I – PG-71.2 – Every safety valve or safety relief valve shall be connected so as to stand in an upright position, with spindle vertical. EXCEPTION: PEB-15.3 (Electric Boilers) – Safety and safety relief valves shall be mounted in accordance with PG-71.2 with the spindle vertical. Electric boilers that do not exceed the diameter, volume, or pressure limits of PMB-2, may have a spring-loaded safety or safety relief valve(s) installed in other than the vertical position, provided that:

  • The valve design is satisfactory for such position
  • The valve is not larger than NPS ¾ (DN20)
  • The maximum angle of deviation from vertical does not exceed 30 degrees
  • The nozzle location is such that no material that could interfere with the operation of the valve can accumulate at the valve inlet
  • The discharge opening of the valve body and discharge piping is oriented so that drainage is adequate

Section IV – Article 7 HG-701.1 – Safety valves and safety relief valves shall be installed with their spindles vertical. Article 8 HLW-810.2 – Safety relief valves shall be installed with their spindles upright and vertical with no horizontal connecting pipe, except that, when the safety relief valve is mounted directly on the water heater vessel with no more than 4 in. (102 mm) maximum interconnecting piping, the valve may be installed in the horizontal position with the outlet pointed down.

Section VIII – APPENDIX M-12 – Spring loaded safety and safety relief valves normally should be installed in the upright position with the spindle vertical. Where space or piping configuration preclude such an installation, the valve may be installed in other than the vertical position provided that:

  • The valve design is satisfactory for such position
  • The media is such that material will not accumulate at the inlet of the valve
  • Drainage of the discharge piping is adequate

More information: 3 things to avoid when installing and operating safety relief valves

How often should I test / inspect my valve?

You should perform inspection, testing, and maintenance on a regular basis. The precise length of time depends on the service conditions, valve condition, and level of performance desired.

We recommend an initial inspection interval of no longer than 12 months.

For valves equipped with a lift lever, we recommend a monthly “try lever test” to ensure the disc is free. The valve should be subjected to at least 75% of set pressure and allowed to snap shut for best leak-tight performance. Use appropriate personal protection equipment (hearing, eye, and temperature protection) as steam and/or high temperature high pressure media may be discharged from the outlet and other openings in the valve such as vent and drain holes. A “try lever test” for high temperature hot water boilers can be performed only when water temperature is below 200°F.

What is ValvKeep?

ValvKeep, from GE, is an online database that stores historical valve data that can be used to anticipate future service needs. This allows you to reduce downtime via a manageable maintenance schedule.

Are there any programs available to help me select a valve?

Yes! GE/Consolidated offers a Pressure Relief Valve Sizing and Selection program to hep you select the appropriate valve for your application.

Process data required:

  • Operating and set pressure
  • Operating and relieving temperatures
  • Required capacity
  • Molecular weight
  • Ratio of specific heats and compressibility factor (for steam, vapor or gas valves
  • Specific gravity and density (for liquid valves)

What is the proper way to install a safety or safety relief valve?

Safety and safety relief valves should be installed vertically with the drain holes open or piped to a convenient location. All piping must be fully supported.

More information: 3 things to avoid when installing and operating safety valves


What certified documents does Allied Valve Inc. provide?

We provide numerous documents including:

  • Certification test reports
  • Certificates of conformance
  • Seat leakage test reports
  • Hydrostatic test reports
  • Certified mill test reports
  • Certified drawings

**All documentation must be requested at the time of order. Charges may apply.

What is Allied Valve Inc.’s standard return policy?

  • All returns must be issued a Return Authorization (RA) number, which can be obtained by contacting our inside sales department.
  • A restocking fee may apply. Please contact our inside sales department for our standard return fees and/or return instructions.
  • All valves being returned for credit are subject to a final inspection, where it will be determined if credit can be issued.

What is Allied Valve Inc.’s standard warranty policy?

Allied offers a one year warranty on all valves, new or reconditioned, and extends the factory warranty to all customers on new products. All reconditioned valves are subject to the same stringent quality control and serializing standards used to handle new ASME code safety valves. Upon completion of service, Allied locks the external adjustments of all safety valves with lead seals bearing the Allied logo. As a further assurance to our customers, Allied carries product liability insurance.