Brand: Masoneilan

Masoneilan 174 Series Spring Loaded, Direct-Operated Reducing or Back-Pressure Regulator

Name: Masoneilan 174 Series Regulator – Datasheet & Price Quote
Brand: Masoneilan

Description

Overview

The Masoneilan 174 Series regulators are spring loaded, direct operated regulators for pressure reducing or relief applications in a variety of industrial applications. The large diaphragm area provides more accurate control at low pressure settings, and the lever design provides excellent shut-off tightness.

Available in 1/2 inch up to 1-1/2 inch (DN15 through DN40) body sizes, the 174-1 reducing version handles inlet pressures up to 145 psig (10 barg), depending on orifice size and outlet pressure setting, while the 174-7 relief version is limited to 4.4 psig (0.3 barg) inlet. The datasheet publishes capacities as gas flows in SCFH (Nm3/h).

Engineering & Design

The simple construction makes the regulator very flexible, easy to install, and easy to maintain. Design features include flow to open or close arrangement depending on the function, internal pressure sensing, a resilient single seat, and an elastomeric diaphragm.

The flexible body orientation simplifies installation in tight piping arrangements, and the two main functions cover the principal pressure control duties: the 174-1 for pressure reducing and the 174-7 for back-pressure and pressure relief.

Key Features

Spring loaded, direct operated
Pressure reducing or relief functions
Large diaphragm area for low pressure control
Lever design for shut-off tightness
Internal pressure sensing
Resilient single seat
Elastomeric diaphragm
Flow to open or close design
Flexible body orientation
1/2 to 1-1/2 inch body sizes

Applications

Pressure reducing regulation
Back-pressure and relief protection
Gas and air distribution systems
Instrument air regulation
Process utility control

Specifications

Specification	Value
Manufacturer	Masoneilan (Baker Hughes)
Series	174
Function	174-1 reducing, 174-7 back-pressure/relief
Service	Gas, air
Sizes	1/2 to 1-1/2 inch (DN15-DN40)
Max Inlet	174-1 reducing: 145 psig (10 barg), depending on orifice size and outlet setting; 174-7 relief: 4.4 psig (0.3 barg)
Operation	Spring loaded, direct operated
Sensing	Internal pressure sensing (no external sensing line)
Max Outlet Pressure	174-1 reducing: 8.8 psig (0.61 barg)
Set Pressure Range	174-1: 1.4 in. w.c. to 8.8 psig; 174-7: 1.4 in. w.c. to 4.4 psig
Temperature Range	-0.4°F to 194°F (-18°C to 90°C)
End Connections	NPT or GAS
Directives	PED 2014/68/EU, ATEX 2014/34/EU
Weight	30 lbs (13.5 kg)
Seat	Resilient single seat
Diaphragm	Elastomeric

For pressure regulation duties, the Masoneilan 174 series regulator is the proven instrument, and Seven Star LLC supplies the Masoneilan 174 series regulator with sizing support for your application.

The Masoneilan 174 series regulator controls the downstream pressure of the gas with the spring loaded diaphragm. The regulator is installed in the pipeline and the set pressure is adjusted with the adjusting screw of the bonnet. The regulator is suitable for the reducing and the back pressure service of the plant.

The 174 series regulator senses the downstream pressure internally, so no external sensing line is required; the downstream set point is adjusted with the adjusting screw while the outlet pressure is checked on a gauge in the downstream piping. The internal parts are serviced without the removal of the regulator from the pipeline, and the diaphragm and the seat are replaced as the spare kit. The regulator body and the trim are available in the materials for the specific gas analysis of the application. The leakage test is performed after the re-assembly.

The 174 series regulator is installed in the fuel gas and the instrument air lines of the plant, and the outlet pressure is set for the consumer downstream of the regulator. The unit is mounted in the horizontal line with the flow direction arrow of the body. The spring range is selected for the outlet pressure of the application and the spare diaphragm kit is kept for the service.

Why Seven Star LLC

Seven Star LLC supplies the Masoneilan 174 Series regulator for pressure control projects across the Gulf, with verified specifications and technical support. Our team assists with function selection, sizing, and spare diaphragm and seat planning.

We serve oil and gas, process, and utility customers with reliable B2B supply of regulators throughout the GCC.

Installation & Operation

The regulator installs in the piping with the body orientation selected for the installation, and the internal pressure sensing eliminates the external impulse line of conventional regulators. The large diaphragm provides accurate control at low pressure settings.

Maintenance focuses on the diaphragm, seat, and spring, all of which are accessible in the simple construction, and the lever design maintains the shut-off tightness over the service life.

Request a Quote for Masoneilan 174 Series Spring Loaded, Direct-Operated Reducing or Back-Pressure Regulator

For the Masoneilan 174 series regulator or any related control and instrumentation requirement, contact the Seven Star LLC team. Submit a formal inquiry through our RFQ page with your valve size, actuation and process data, and our specialists will respond with a detailed commercial proposal and the official Masoneilan documentation.

How to Specify a 174 Series Regulator

Self-operated regulators are simple devices, but only when they are selected for the real operating conditions. To size a 174 Series unit correctly, prepare the following data:

Function: pressure reducing (174-1) or back-pressure/relief (174-7).
Fluid: gas type or air, with any contaminants or moisture that could affect elastomers.
Inlet pressure range: minimum and maximum, within the 145 psig (10 barg) limit of the 174-1 (4.4 psig on the 174-7) and the datasheet table of maximum operating inlet pressures for the orifice and outlet setting.
Set pressure and allowable deviation: this decides the spring range.
Flow rates: minimum, normal and maximum.
Line size and end connections of the existing piping.
Temperature range, to confirm the diaphragm and seat materials.

Avoid oversizing. A regulator that is too large for the flow will work close to its seat, which can cause hunting and faster seat wear. When replacing an existing unit, the nameplate on the body or bonnet normally shows the model, size and spring range; send a photo of it with your enquiry.

Troubleshooting Common Problems

Outlet Pressure Creeps Up at Zero Flow

This usually points to seat leakage. Inspect the resilient seat and the orifice for damage or debris, and check that dirt from the line has not lodged under the seat. An upstream strainer helps prevent repeat failures.

Unstable or Hunting Pressure

Check for oversizing, very low flow for long periods, or a spring range that is too wide for the set pressure. Sudden large changes in downstream demand can also cause cycling.

Outlet Pressure Falls Under High Flow

Some droop is normal with direct-operated regulators. If it is more than the process allows, check the sizing or consider a larger body size.

Gas Escaping from the Bonnet Vent

This suggests a damaged diaphragm, which should be replaced with a proper spare kit.

Use in Oman and the GCC

The 174 Series is common on instrument air headers, fuel gas feeds to small burners and heaters, and blanketing and utility gas lines. In hot, dusty locations, protect vents from blockage and check elastomer parts at each overhaul.

Sourcing Through Seven Star LLC

Send Seven Star LLC your process data or nameplate photo, and we will reply with a quotation and lead time for regulators or spare kits.

Related Products

Single-model pages for the 174 Series are the Masoneilan 174-1 low pressure reducing regulator and Masoneilan 174-7 low pressure relief regulator.

Datasheets & Documents

Datasheet Masoneilan 174 Series Spring Loaded, Direct-Operated Reducing or Back-Pressure Regulator Datasheet Download

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About brand

Masoneilan is a control valve brand of Baker Hughes with roots going back to 1882. Its Camflex eccentric plug rotary valve, 21000 series globe valve and SVI digital positioners are fixtures in refineries, gas plants and power stations. Every valve carries a serial number and a long model number that define the actuator, body and trim.

Seven Star LLC is an independent supplier listing Masoneilan control valves, actuators, regulators, positioners and level instruments for buyers in Oman and the GCC. We source complete valves as well as Masoneilan spare parts against that nameplate data.

Masoneilan at a glance

Origin	Mason Regulator Company, Boston area, USA (1882). It acquired the Neilan Company of California in 1931, and the two names became Masoneilan.
Ownership	Dresser Industries from 1985, then GE Oil & Gas, now Baker Hughes
Milestones the company cites	Cv flow coefficient introduced (1944), spring-diaphragm actuators (1955), Camflex rotary globe valve (1968), Lo-dB low-noise trim (1975), LincolnLog axial-flow letdown valve (1982), Varipak (1984), V-Log (1998), SteamForm steam conditioning valve (2002)
Product families	Globe, rotary, butterfly and severe-service control valves, actuators, digital positioners, self-operated regulators and displacer level instruments
Typical duty	Throttling control of steam, gas, hydrocarbons and water, high-pressure letdown, anti-cavitation and low-noise service

Masoneilan control valves and actuator series

Series	Type	Typical use
21000, 21009	Top-guided and cage-guided globe valves	General process control. Cryogenic (21000 C), bellows seal (21000 BS) and API 6A versions are also made
41005	Cage-guided globe valve	Higher pressure drop and larger sizes, up to 30-36 inch extended sizes; VRT anti-cavitation and API 6A versions
35002 Camflex II	Eccentric plug rotary control valve	Erosive, flashing and dirty service; HC high capacity, DVD low noise and GR globe replacement versions
37002 MiniTork II, 39003/39005, 33000	Butterfly control valves, high-performance and triple-offset	Large flows at low pressure drop, and tight-shutoff duty
28000 Varipak	Microflow control valve	Very small flows, with adjustable Cv
78400/18400 LincolnLog, 77000, 49000 V-Log	Severe-service multi-stage valves	High-pressure liquid letdown, anti-cavitation and gas noise reduction
84000/84003 SteamForm, DSH	Steam conditioning valves and desuperheaters	Turbine bypass and steam pressure and temperature reduction
87/88, 37/38, 51/52/53	Spring-diaphragm and piston actuators	Linear and rotary valve actuation; diaphragms and soft-goods kits are listed separately
SVI3, SVI II AP, SVi1000, SVI FF	Digital valve positioners	HART or FOUNDATION Fieldbus positioning with valve diagnostics; the SVI II ESD adds partial stroke testing
4700/4800, 8013	Pneumatic and electro-pneumatic positioners	Older installed base. Many sites move to SVI positioners at overhaul
525/526, 535/536, 171-174	Self-operated pressure regulators	Pressure reducing and back-pressure control without external power
12400, 12800	Displacer level transmitters and controllers	Digital (12400, HART, SIL 2 version 12420) and pneumatic (12800) level control on separators and vessels

Where Masoneilan valves are used

Throttling duty on steam, hydrocarbons, gas and water is the daily work of these valves. Typical services are feedwater and steam conditioning in power plants, separator and compressor loops in gas processing, high-pressure-drop letdown, cryogenic service in LNG and air separation, and general flow, pressure and level control in refineries and chemical plants.

Ordering Masoneilan valves and spare parts: what we need

For spare parts the serial number decides the order, because the factory record behind it lists the trim, materials and actuator. Send a clear nameplate photo with the serial number, model number, size and pressure class. For a new valve, add the process data: fluid, inlet and outlet pressure, temperature, minimum, normal and maximum flow, required leakage class, fail position, air supply and control signal. When an older positioner or valve series is no longer made, we quote the successor that Baker Hughes names and list the mounting kit it needs.

Facts checked against Baker Hughes Masoneilan product information and the company's published timeline, October 2026.

Browse Masoneilan products by category: Control Valves, Valve Actuator, Regulators, Valve Positioner, Level Transmitter.

FAQ

Questions about the Masoneilan 174 Series Spring Loaded,

Answers from our engineering team on installation, compatibility and integration.

01What is the 174 Series?

It is a Masoneilan (Baker Hughes) spring loaded, direct operated regulator for pressure reducing or relief applications. Pressure sensing is internal, so no external sensing line is needed.

02Which sizes are available?

1/2 inch up to 1-1/2 inch (DN15 through DN40) body sizes.

03What is the maximum inlet pressure?

The 174-1 reducing version handles inlet pressures up to 145 psig (10 barg), depending on orifice size and outlet pressure setting as given in the datasheet table of maximum operating inlet pressures. The 174-7 relief version is limited to 4.4 psig (0.3 barg) inlet.

04Which functions are covered?

174-1 for pressure reducing and 174-7 for back-pressure and pressure relief.

05Which services is it used for?

Gas and air services in a variety of industrial applications.