Masoneilan 525-526 Series

Top and Bottom Guiding

A well accepted industry standard particularly suited for double seated plugs to provide adequate support against side loads.

High Capacity with Low Recovery

Flow capacity is at top levels for contemporary double seated regulators and is attained with very little pressure recovery as indicated by a high critical flow factor.

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Reduced Capacity Trim

0.4 Factor Trim – the most practical double seated trim design giving a substantial reduction in capacity while maintaining desirable flow characteristics.

High Performance Materials

Materials of construction have been selected for high performance and long life when handling the high pressure drop capabilities of the valve.

High Temperature Applications

For temperatures over the rating of the diaphragm material, the regulator must be mounted with the actuator below the centerline of the regulator body. The diaphragm will be protected from the high temperature by a condensate barrier in the sensing line and actuator diaphragm case. If installed otherwise, an adequate condensate barrier must be incorporated. Consult factory for more information.


Models 525 and 526 Regulators are designed for use with the 10900 Series Actuators for reducing, back pressure and differential pressure applications.

General Data


Pressure Reducing                           525

Differential Pressure Reducing      525-50

Back Pressure                                    526

Differential Back Pressure              526-50


Steam, Gas, Liquids


¾” through 4” (20 through 100 mm)

Ratings & Connections

Flanged : ASME CL150-600

Welded : BW or SW

Screwed : NPT ¾” through 2” (20-50 mm)


Type : High Capacity Globe with Double Seated Top and Bottom Guided Plug

Materials :  Carbon steel, stainless steel


Plug Type : Disc

Seat Ring : Threaded

Guide : Heavy Top and Bottom Guided

Capacity : Full Area, Reduced Capacity in All Sizes


Type : 10900 Spring Diaphragm