DUNGS MB-DLE 407 B01 S50 GasMultiBloc Rp 3/4, 230 V
Overview
The DUNGS MB-DLE 407 B01 S50 is one specific size and version of the Karl Dungs GasMultiBloc: a compact fitting that combines a dirt trap, a pressure regulator and two safety shut-off solenoid valves in a single aluminium body. The 407 designation means a DN 20 body with a double-seat second valve, B01 means one regulator and two Class A valves for single-stage operation, and S50 means both valves are switched together with an outlet pressure range of 4 to 50 mbar. Fitted with Rp 3/4 flanges and a 230 V coil set, this is the gas train used on many commercial forced-draught burners in the 60 to 320 kW class, including the Bentone BG 400 single-stage burner.
Seven Star LLC supplies the DUNGS MB-DLE 407 B01 S50 to boiler service contractors, burner builders and plant maintenance teams in the Sultanate of Oman and across the GCC, with engineering support in Muscat. The wider family, covering the 405, 410 and 412 sizes, is described on our Dungs MB-DLE 405-412 B01 GasMultiBloc Combined Regulator and Safety Valves page; this page focuses on the exact 407 B01 S50 configuration that is most often requested as a direct replacement on installed burners.
Operating Principle
Gas enters the inlet flange and first passes a fine mesh-sieve that protects the valve seats and the regulator diaphragm from pipeline debris. Valve V1 is a fast-opening, fast-closing solenoid valve to DIN EN 161 Class A Group 2. Downstream of V1 the proportional regulator, built to DIN EN 88 Class A Group 2 and compensated for residual pressure, holds the burner-side pressure at the value set on the spring. In the S50 version the fixed setpoint spring covers 4 to 50 mbar, which suits burners fed from a normal low-pressure supply and needing a relatively high head pressure at full load. When the burner stops, V1 provides the leak-tight closure for the regulator, and because an internal pulse tap is fitted, no vent line above the roof is needed.
Valve V2 in the DUNGS MB-DLE 407 closes fast but opens slowly. A hydraulic brake delays the opening, and the datasheet gives an opening time of up to 20 seconds for MB-DLE versions, while the main volume restrictor on V2 limits the maximum flow. The Bentone BG 400 manual describes the same arrangement as slow-opening valves with adjustable start load and maximum flow. In practice the DUNGS MB-DLE 407 gives a soft, controlled light-off with less pressure surge in the combustion chamber, which reduces nuisance flame failures and mechanical stress on the burner head and boiler.
Engineering Design of the DUNGS MB-DLE 407
The housing of the DUNGS MB-DLE 407 is aluminium die casting; diaphragms and seals are NBR-based with Silopren silicone rubber, and the solenoid drive is made of steel, brass and aluminium. The 405 and 407 bodies share the same outer dimensions, so the 407 can take Rp 1/2 or Rp 3/4 flanges and combinations of the two; the version on this page uses Rp 3/4 threads to ISO 7/1. The dimension table for the MB-DLE 405/407 gives dimension a as 110 mm, b as 151 mm and h as 115 mm, plus a 185 mm space requirement for exchanging the solenoid, and a weight of 2.6 kg. The difference between a 405 and a 407 is the second valve: a single seat in the 405 and a double seat in the 407, which gives the 407 a higher flow for the same body size.
Electrical connection of the DUNGS MB-DLE 407 is by plug to DIN EN 175301-803 for the valves and any mounted pressure switch, supplied at 220 to 230 V AC, 50 to 60 Hz, with a tolerance of minus 15 to plus 10 percent. For the 405/407 S50 the rated power consumption is 36 VA at 230 V and 20 degrees Celsius, the switch-on duration is 100 percent and the enclosure is IP 54. Measuring and ignition gas connections are G 1/8 screw plugs, there is a test nipple on the inlet side, and a GW A5 or GW A2 pressure switch can be mounted directly on the block. The DUNGS MB-DLE 407 may be installed with the solenoid upright, horizontal or at any position in between.
Key Features
The DUNGS MB-DLE 407 B01 S50 brings the following practical advantages to a single-stage burner gas train:
- The filter, regulator and two Class A safety valves are combined in one short, light assembly instead of four separate components.
- The S50 regulator spring gives an outlet pressure range of 4 to 50 mbar with a maximum operating pressure of 360 mbar.
- The double-seat V2 of the 407 size delivers more flow than the single-seat 405 in the same compact DN 20 housing.
- A hydraulic opening delay and a main volume restrictor on V2 give a smooth, adjustable light-off.
- Both valves are controlled together in the S50 version, so a single valve output from the burner control is sufficient.
- An internal pulse tap removes the need for an external impulse line or a vent line to atmosphere.
- A minimum gas pressure switch and a VPS 504 valve proving system can be added within the modular system.
- EU type examination covers the Gas Appliances Regulation and the Pressure Equipment Directive.
Industrial Applications
The DUNGS MB-DLE 407 is fitted on forced-draught gas burners for hot water and steam boilers, air heaters, dryers, bakery ovens and similar process heat equipment. It is suitable for gases of families 1, 2 and 3 and other neutral gaseous media, which covers natural gas and gaseous LPG. The datasheet notes that in liquid gas systems the unit must not be operated below 0 degrees Celsius and is only suitable for the gaseous phase; the ambient range is minus 15 to plus 70 degrees Celsius, which suits enclosed boiler rooms in the Gulf climate.
In Oman these gas trains are found in hotel, hospital and laundry boiler houses in Muscat, in food processing plants in Rusayl and Sohar, and in process heaters in Salalah. Seven Star LLC supplies the DUNGS MB-DLE 407 B01 S50 together with related parts such as the Dungs GW A6 Compact Pressure Switch for Gas and Air, the DUNGS VPS 504 219881 and the DUNGS DMV-D 507/11 Double Solenoid Valve, so a burner gas train can be serviced with one order to a GCC supplier.
Technical Specifications
The values below for the DUNGS MB-DLE 407 B01 S50 are taken from the manufacturer datasheet for the MB-D(LE) 405-412 B01 series attached to this page.
| Parameter | Specification |
|---|---|
| Model | DUNGS MB-DLE 407 B01 S50, GasMultiBloc, single-stage function |
| Nominal size | DN 20, V2 double-seat valve |
| Flange threads | Rp 3/4 to ISO 7/1 (405/407 body also accepts Rp 1/2) |
| Max. operating pressure | 360 mbar (36 kPa) |
| Outlet pressure range (S50) | 4 – 50 mbar (0.4 – 5 kPa) |
| Valve control | V1 and V2 controlled together (S50) |
| Valves | DIN EN 161 Class A Group 2; V1 fast opening; V2 slow opening with main volume restrictor |
| Opening time V2 | Below 20 s (MB-DLE) |
| Regulator | DIN EN 88 Class A Group 2, fixed setpoint spring, internal pulse tap |
| Filter | Fine mesh-sieve |
| Voltage | 220 – 230 V AC, 50 – 60 Hz, −15 % / +10 % |
| Power consumption | 36 VA (MB 405/407 S50, 230 V, 20 °C) |
| Protection / duty | IP 54, 100 % switch-on duration |
| Ambient temperature | −15 °C to +70 °C |
| Gas connections | G 1/8 measuring and ignition gas taps |
| Weight | 2.6 kg |
How to Order
To order the DUNGS MB-DLE 407 B01 S50, send Seven Star LLC an RFQ with the type code from the label, the flange size and coil voltage, or the burner model it serves. Our instrumentation team in Muscat checks the selection against the datasheet, shares the document for download and arranges delivery to sites in Oman and across the GCC.
- Datasheet DUNGS MB-D(LE) 405-412 B01 Datasheet (manufacturer, Ed. 03.19, No. 214 762) - covers MB-DLE 407 B01 S50 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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