How to Cross-Reference & Replace Any Safety Valve with an Aquatrol Equivalent

Why Cross-Referencing Matters for Safety Valve Replacement

When a safety relief valve reaches the end of its service life, fails an inspection, or needs to be replaced during a shutdown, you need an exact functional match — not just a valve that looks similar. The replacement must match the original’s ASME code certification, set pressure, capacity, connection sizing, and service type. Getting any of these wrong means a failed inspection, an unsafe system, or both.

The challenge is that many facilities were originally equipped with valves from manufacturers like Kunkle (now Emerson), Conbraco/Apollo, Watts, or Consolidated, and those exact models may be discontinued, backordered, or priced at a premium. Cross-referencing to an Aquatrol equivalent gives you an ASME-certified, NB-registered replacement that meets the same specifications — often with shorter lead times and better pricing through factory-direct Aquatrol distribution.

What You Need Before You Start

Before cross-referencing, gather these five specifications from your existing valve’s nameplate:

1. ASME Code Section — Section I (“V” stamp) for power boilers or Section VIII (“UV” stamp) for unfired pressure vessels. The replacement must carry the same certification.
2. Set Pressure — The exact pressure in psig at which the valve opens. This must match your system’s Maximum Allowable Working Pressure (MAWP) requirements per ASME code.
3. Rated Capacity — The certified flow rate in SCFM (air/gas), lb/hr (steam), or GPM (liquid). The replacement valve’s capacity must meet or exceed this value.
4. Inlet and Outlet Size — Nominal pipe size and connection type (NPT, flanged, etc.). Example: 1″ MNPT inlet x 1-1/4″ FNPT outlet.
5. Service Type — Steam, air/gas, liquid, or combination. This determines the required seat material (metal for steam, elastomer for air/gas/liquid).

Common Cross-Reference Scenarios

Replacing Kunkle Series 6000 Valves

Kunkle (now part of Emerson) Series 6000 valves are among the most commonly replaced safety valves in the field. Here is how the Kunkle models map to Aquatrol equivalents:

• Kunkle 6010 (bronze body, side outlet, full nozzle, brass/bronze trim) — The Aquatrol Series 740 is the direct functional equivalent. Both are bronze/brass body construction with ASME Section VIII (“UV”) certification. Match your inlet/outlet size and orifice designation.
• Kunkle 6021 (same as 6010 with PTFE/PFA disc insert) — Cross-reference to the Aquatrol Series 740 with PTFE seat option. The PTFE seat provides the same chemical resistance and low-temperature capability.
• Kunkle 6030 (same as 6010 with stainless steel trim — nozzle and disc) — The Aquatrol Series 741 matches this configuration with full stainless steel internals (nozzle, ring, disc, springs) in a bronze/brass body.
• Kunkle 6182/6283 (flanged connections) — Cross-reference to the Aquatrol Series 740 or 741 with flanged option. Aquatrol offers lap joint flange and ANSI flanged configurations.

Replacing Conbraco/Apollo Valves

Conbraco (Apollo) safety valves are common in HVAC, plumbing, and light industrial applications. When replacing with Aquatrol:

• Match the ASME section (most Conbraco safety valves are Section VIII “UV” certified)
• Verify the set pressure and capacity meet your requirements
• The Aquatrol Series 740 covers the same pressure range (up to 350 psig air/gas/liquid in standard brass) and connection sizes (1/2″ through 3″ NPT)

Replacing Consolidated or Dresser Valves

Consolidated (now part of Baker Hughes) valves are typically found in process and refinery applications. For direct replacements:

• The Aquatrol Series 742 (carbon steel body, stainless steel internals) covers applications where a steel body valve is required
• The Aquatrol Series 743 (100% stainless steel) covers corrosive service applications
• Both are rated to 1,500 psig for air/gas/liquid and 300 psig for steam

Step-by-Step Cross-Reference Process

Step 1: Identify Your Current Valve

Read the nameplate on your existing valve. Record the manufacturer, model number, set pressure, capacity, size, and ASME code stamp. If the nameplate is unreadable, measure the physical dimensions (inlet/outlet pipe size, overall height, face-to-face dimension) and note the body material.

Step 2: Use Our Cross-Reference Tool

Visit our Cross-Reference page and enter your existing valve’s manufacturer and model number. The tool will return the matching Aquatrol series and configuration.

Step 3: Verify the Match

Confirm that all five critical specifications match:

• ASME code section and designator (V, UV, or HV)
• Set pressure is available in the Aquatrol series for your required psig
• Rated capacity meets or exceeds your system’s relieving requirement
• Physical connections (NPT size, flanged rating) match your piping
• Temperature range covers your operating conditions

Step 4: Check Orifice Designation

ASME-coded valves use standard orifice letter designations (D, E, F, G, H, J) that correspond to specific effective discharge areas. The replacement valve’s orifice must provide equal or greater effective area than the original. Aquatrol 740 Series valves are available with standard ASME orifice designations.

Step 5: Order or Request a Quote

Once you have confirmed the match, you can order directly from our online store or request a custom quote for non-standard configurations. Aquatrol valves ship from stock for most standard configurations, so lead times are typically shorter than OEM replacement parts.

Key Specifications Comparison Table

Common Mistakes to Avoid

• Matching on size alone: A 1″ valve from one manufacturer does not automatically replace a 1″ valve from another. You must verify capacity, set pressure, and code certification.
• Ignoring the seat material: If the original valve has a metal seat for steam service, replacing it with an elastomer seat valve will fail in steam applications. Always match seat material to service type.
• Overlooking back-pressure: If your system has significant built-up or superimposed back-pressure, you may need a balanced bellows design. Standard conventional valves are affected by back-pressure, which reduces effective capacity.
• Using Section VIII valves on Section I boilers: ASME Section VIII “UV” stamped valves cannot be used on power boilers that require Section I “V” certification. The performance requirements are different — Section I valves must reach full lift at 3% overpressure, while Section VIII valves are allowed up to 10% overpressure.

Frequently Asked Questions

Can I replace a Kunkle valve with an Aquatrol valve without re-engineering?

Yes, provided the five critical specifications match (ASME code, set pressure, capacity, size, and service type). Aquatrol valves are independently ASME-certified and NB-registered, so they are accepted as equivalent replacements by inspectors and jurisdictional authorities. No re-engineering of the piping system is needed when the replacement is a functional match.

Will the inspector accept a different brand as a replacement?

Inspectors verify that the installed valve meets the ASME code requirements for the vessel — not that it is a specific brand. As long as the replacement carries the correct ASME certification mark, NB registration, and meets the set pressure and capacity requirements stamped on the vessel’s nameplate, any ASME-certified manufacturer’s valve is acceptable.

What if my valve model is discontinued?

Many older valve models from Kunkle, Consolidated, and other manufacturers have been discontinued due to corporate acquisitions and product line consolidation. Send us the old nameplate information and we will identify the correct Aquatrol cross-reference. Our team handles discontinued valve replacements daily.

How do I handle flanged valve replacements?

For flanged valves, in addition to the five critical specifications, you need to match the flange rating (150#, 300#, etc.), face type, and bolt pattern. Aquatrol offers lap joint flange and ANSI flanged options on the 740, 741, 742, and 743 series. Contact us with your flange specifications for a precise match.

Ready to find your replacement? Use our Cross-Reference Tool to find your Aquatrol equivalent, try the Valve Finder to search by specification, or contact us with your existing valve’s nameplate photo for a same-day cross-reference.