What are Regulating Valves used for?

Regulators are simple, cost-effective valves used for:
• Reducing Pressure (PRV)
• Controlling Temperature
• Controlling Back Pressure

Unlike control valves, regulators are self-powered, which means they do not require any outside source of power such as air pressure or electric actuators to operate.

Controlling Pressure

The most common application for regulating valves is for reducing the downstream pressure of Steam, Water, as well as other liquids and gases that are flowing thru a pipe or system. When regulators are used for pressure reduction applications they are often referred to as Pressure Regulating Valves or Pressure Reducing Valves or simply PRV’s.

Controlling Temperature

Regulators can also be used to precisely control the flow of steam to accurately heat other liquids such as water flowing in a Heat Exchanger or contained in a Tank or Vat to extremely accurate temperatures. Regulators can also be used to accurately control the flow of water or glycol to cool down a process to a precise value. When regulators are used for any type of temperature control they are referred to as Temperature Regulators Valves or just Temperature Regulators.

Back Pressure Control

Regulating Valves can also be used to relieve over pressure conditions in Liquid systems or to maintain the “Back Pressure” in steam systems. When regulating valves are used in these types of applications they are referred to as Relief or back pressure Valves. Back pressures regulating valves used in steam applications must not to be confused with Safety Relief Valves.

What are Pressure Regulating Valves (PRVs) used for?

Steam, liquids, and other gases are typically transported through piping systems at relatively higher pressure than ultimately required and therefore need to be reduced to a lower pressure at the final point of use. The purpose of the Pressure Regulating Valve (PRV) is to reduce the pressure of steam, liquid, or gas to a lower pressure appropriate for its final application. Direct operated regulators are typically the most economical and can be a suitable choice particularly in the low to medium flow range. Pilot Operated Regulators, such as the HD-Series will control downstream pressure more accuratly over a wider range of flows.

Pressure Regulators for STEAM Applications

HD Series - Pilot Operated

1/2” - 6” • Ductile Iron Body
Used for pressure reduction or temperature control applications depending on pilot selection. Commonly used for reducing steam pressure to a specific downstream set pressure, other pilots are also available for controlling temperature, back pressure, and other applications.


1/2” - 2” • Ductile Iron or Stainless Steel Body
Simplest and most economical choice for Pressure Reducing applications for a variety of fluids including Steam, Water, Air, and other liquids and gases. These direct operated regulators have limited capacity compared to the HD-Series pilot operated regulators.

455 Series

1/2” - 4” • Bronze / Cast Iron Body
For reducing pressure on Steam & Air applications. An external pressure sensing connection is required. The lack of small pilot orifices make the 455 Series less susceptible to dirt and scale. Balanced seat and disc design allows these valves to be used in applications with low inlet pressure down to 5 psig.

403 Series - Pilot Operated Reduction

1/2” - 4” • Ductile Iron Body
The 403 are pilot-operated, piston-actuated, pressure regulators primarily used for reducing pressure in STEAM systems. Available with an optional internal sensing line which simplifies installation. Piston Operated regulators are more compact in size when compared to typical diaphragm actuated regulators.

Pressure Regulators for WATER Applications


1/2” - 4” • Bronze / Cast Iron Body
These are the primary choice for reducing pressure on Water, Air, and other liquid and gas applications. The soft-seated elastomeric Viton disc has an operating temperature up to 300 ºF and provides excellent shut-off characteristics. The balanced seat design eliminates internal forces extending the capability range of both pressure and capacity.

What are Temperature Regulating Valves used for?

Temperature regulators can be used to control temperature in various processes and systems. Typical configurations consist of a temperature probe (“bulb”) connected by a length of capillary tubing to a bellows in the valve or pilot actuator. When the temperature bulb is heated, the liquid inside the probe expands the bellows and closes off the valve or pilot. The opening and closing of the valve controls the flow of the fluid (typically steam or water) which maintains system or process temperature.

Regulating Valves for HEATING Applications

Regulating Valves for COOLING Applications

Back-Pressure and Relief Valves

Relief Valves (Back Pressure Valves) are used to maintain a specific back pressure or to protect systems from an over-pressure condition.

Back-Pressure Valves for STEAM Applications

PBP Back-Pressure Pilot

The PBP Back-Pressure Pilots are used with HD Regulators to maintain upstream pressures in steam systems. When the upstream pressure reaches the pilot set point, the regulator opens. The HD Regulator with a PBP Back-Pressure Pilot is commonly used to supply steam to low-pressure mains. The PBP Back-Pressure Pilot maintains a constant back-pressure on the inlet side of the regulator. Should not be used in place of a safety relief valve.

Relief Valves for LIQUID Applications

Primary choice for pressure reduction or temperature control in steam application. Various pilots available for reducing pressure, controlling temperature, and other applications.
General Purpose regulator for pressure reducing applications. Primarily used for Steam, Water, Air, and other liquids and gases. Cast Iron and Stainless Steel version available.
The 403 Series are pilot-operated, piston-actuated, pressure regulators primarily used for reducing pressure in STEAM systems. Available with an optional internal sensing line which simplifies installation. Piston Operated regulators are more compact in size when compared to typical diaphragm actuated regulators.
The 455 Series is an alternative to the HD Pilot Operated type regulator. These Direct Operated Regulators are less susceptible to fouling from dirt and scale. Primarily used for Steam pressure reducing applications.
Primary regulator choice for pressure reducing applications, Water, Air, and other liquids and gases. Soft-seating provides tight shut-off, while the balanced plug and disc design allows for wider range of pressures and flows.
They are recommended for controlling temperature on relatively stable systems, where small valve stroke modulations will correct temperature drift. Where sudden or large load changes, or rapid temperature changes occur, a pneumatically-actuated Control Valve should be considered.
Relief & Back Pressure Regulators prevent over-pressurization by relieving upstream pressure to a lower pressure region. They are designed to open and allow liquid to flow when a specific set pressure is reached. NOT FOR SAFETY RELIEF OR STEAM USE. Commonly used in pump bypass.
The Ambi-Regulator is similar to the W91/94 Series, except the bulb and capillary are removed. This allows the thermal assembly to sense the surrounding conditions which opens and closes the valve based on ambient temperatures. Primarily used on steam tracing lines and can also be used as a freeze protection device on water lines.