Dungs FRS Gas Pressure Regulator Rp 3/8 to DN 150
Overview
The Dungs FRS is a spring-loaded gas pressure regulator with an adjustable setpoint spring, designed for gas burners and gas-fired equipment. It complies with EN 88-1 and DIN 3380 and reduces a supply pressure of up to 500 mbar to a stable outlet pressure between 2.5 and 200 mbar. With threaded sizes from Rp 3/8 and flanged sizes up to DN 150, the Dungs FRS covers everything from a small domestic-scale appliance to a large industrial burner from a single product family.
Seven Star LLC supplies the Dungs FRS to burner OEMs, gas contractors and facility engineers in Oman and the GCC. As a trusted supplier with engineering support in Muscat, we help customers select body size and setpoint spring from flow and pressure data, and we can match replacement units to the order number of an existing regulator.
Working Principle
The regulator works on a force comparison between three forces: the adjustable setpoint spring, the differential pressure acting on the working diaphragm, and the weight of the moving parts. When outlet pressure drops because burner demand increases, the spring force opens the regulating cup further; when outlet pressure rises, the diaphragm force closes it. An inlet pressure compensation diaphragm reduces the influence of supply pressure changes, which gives sturdy, precise and sensitive regulation of the outlet pressure.
The outlet pressure is sensed through an internal pulse tap as standard. An external pulse connection can be ordered on both sides of the housing when the pressure should be controlled at a point further downstream, for example near the burner head. Because safety diaphragms are fitted, the Dungs FRS normally does not need a ventilation pipe to atmosphere, which simplifies installation inside buildings.
Engineering Design of the Dungs FRS
The housing is aluminium and steel, and the seals and diaphragms are NBR. The regulator contains no non-ferrous metals in the gas path and is suitable for dry gases with up to 0.1 vol.% H2S, as well as gases of families 1, 2 and 3 and other neutral gaseous media. Measuring connections are G 1/4 on both sides of the inlet section, and the regulator dome can be installed from vertically upright to lying horizontally.
Threaded models FRS 503, 505, 507, 510, 515, 520 and 525 cover Rp 3/8 through Rp 2 1/2 to ISO 7/1, while flanged models FRS 5040 to FRS 5150 use PN 16 flanges to DIN EN 1092-1 from DN 40 to DN 150. Nine setpoint springs, colour-coded brown, white, orange, blue, red, yellow, black, pink and grey, cover outlet ranges from 2.5–9 mbar to 140–200 mbar; the blue spring No. 4 for 10–30 mbar is fitted as standard.
Key Features
The Dungs FRS offers the following features for burner gas trains:
- The regulator conforms to EN 88-1 Class A Group 2 and DIN 3380, with EC type examination under the Gas Appliances Regulation.
- Inlet pressure up to 500 mbar is reduced to an outlet setpoint between 2.5 and 200 mbar.
- An inlet pressure compensation diaphragm keeps the outlet stable when supply pressure varies.
- Safety diaphragms are installed, so a vent line is needed only in special cases.
- Internal pulse tapping is standard, with optional external pulse connections on both sides.
- Sizes run from Rp 3/8 threaded to DN 150 flanged, sharing one spring and setting concept.
- The gas path is free of non-ferrous metals and tolerates dry gas with up to 0.1 vol.% H2S.
- Ambient temperature range is −15°C to +70°C, suitable for plant rooms and outdoor gas skids under cover.
Industrial Applications
The Dungs FRS is used upstream of burner safety valves on boilers, thermal oil heaters, industrial ovens, kilns, dryers and air heaters, and as an appliance regulator on commercial catering equipment. Gas-conveying lines and pulse lines should be steel of at least PN 1, DN 6, the regulator should be protected by a suitable dirt trap, and condensate must not drain into the housing, points our engineers check during selection. Final sizing follows the flow and pressure drop charts in the manufacturer datasheet, using the correction factor for the actual gas density.
Across Oman, typical sites include hotel and hospital boiler houses in Muscat, food and beverage plants in Rusayl and Sohar, and process-heat equipment in the Salalah free zone. Seven Star LLC supports these users with genuine Dungs FRS regulators together with downstream safety components such as the DUNGS DMV-D 5125/11 ECO double solenoid valve, the Dungs SV-D 505 safety solenoid valve and the DUNGS VPS 504 valve proving system, so a full gas train can be sourced in one GCC order.
Technical Specifications
The main Dungs FRS data from the manufacturer datasheet are shown here:
| Parameter | Specification |
|---|---|
| Model | Dungs FRS 503 / 505 / 507 / 510 / 515 / 520 / 525 (threaded); FRS 5040 / 5050 / 5065 / 5080 / 5100 / 5125 / 5150 (flanged) |
| Connections | Rp 3/8 to Rp 2 1/2 (ISO 7/1); DN 40 to DN 150, PN 16 flange to DIN EN 1092-1 |
| Max. operating pressure | 500 mbar (50 kPa) |
| Inlet pressure range | +5 mbar or p2 +2.5 mbar up to 500 mbar |
| Outlet pressure range | 2.5 to 200 mbar depending on setpoint spring |
| Standard | EN 88-1 Class A Group 2, DIN 3380, RG 10 |
| Setpoint springs | Nine springs from 2.5–9 mbar to 140–200 mbar; blue No. 4 (10–30 mbar) standard |
| Media | Gases of families 1, 2, 3 and neutral gases; dry, max. 0.1 vol.% H2S |
| Materials | Aluminium and steel housing, NBR seals and diaphragms |
| Ambient temperature | −15°C to +70°C |
| Pulse connection | Internal standard; external optional on both sides |
| Weight | 0.6 kg (FRS 503/505) to 38 kg (FRS 5150) |
How to Order
For a Dungs FRS quotation, send Seven Star LLC your RFQ with the model or connection size, required flow rate, inlet pressure and target outlet pressure, or the order number of the regulator being replaced. Our instrumentation division in Muscat recommends body size and spring, confirms availability and delivery time, and provides the manufacturer datasheet for download. Seven Star LLC supplies genuine Dungs FRS gas pressure regulators with engineering support throughout Oman and the GCC.
- Datasheet Dungs FRS Pressure Regulator Datasheet (manufacturer, Ed. 01.18, No. 214 743) Download
DUNGS product families listed here
The listed DUNGS gas valves and controls make up most of a burner gas train. The FRS is a spring-loaded gas pressure regulator in sizes from Rp 3/8 to DN 150. The GW A6 is a compact pressure switch for gas and air. DMV-D double solenoid valves, such as the DMV-D 507/11 and DMV-D 5125/11, combine two safety shut-off valves in one body, and the SV-D is a single safety solenoid valve. The MB-DLE 405 to 412 B01 GasMultiBloc integrates a filter, a regulator and two valves in one compact unit. The VPS 504 is a valve proving system that tests the tightness of the two shut-off valves before burner start.Where DUNGS equipment is used
DUNGS combustion controls are fitted to steam and hot water boilers, thermal oil heaters, air heaters, dryers, ovens, kilns and furnaces, and to the fuel gas lines of gas engines. Buyers in the GCC typically need them as replacements on packaged burners in food plants, laundries, hospitals and building plant rooms.Ordering DUNGS parts: what we need
Send the full type designation and the six-digit article number from the nameplate, for example VPS 504 S04 with 219881, a 230 V version. Add the coil voltage and frequency, the connection (Rp thread or flange DN), and the maximum inlet pressure. For an FRS regulator, state the outlet pressure and the spring range or spring color. For a GW pressure switch, state the setting range, which is part of the type name. For a MultiBloc, say whether operation is single-stage or two-stage. The burner make and model help us confirm the match.Browse DUNGS products by category: Solenoid Valve.
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