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01564 782 776

Smell Gas? Call TRANSCO

0800 111 999

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Gas Safety Valves Product Profile

Magne-flo Excess Flow Valves protect against gas leaks caused by theft, vandalism, deteriorating pipework, human error, or any uncapped DIY situation.

The value activates where there is a break in the pipework, causing an uncalibrated excess flow of gas. The valve stays in the closed position until the repair is carried out and then automatically resets itself.


The objective of the product is to provide the following:

*Application compatibility via a range of performances

*Reliable/accurate/repeatable shut off performance capability

*Simplicity and low cost *Automatic reset capability

*Maintenance/container resistant

*Universal adaptability, installation ease and compatibility with existing hardware

The product is a plate magnet system packaged as a self-contained capsule, which can be easily inserted into a variety of fittings and plumbing fixtures.

How it works

The valve remains in the open position at normal flow rates.
Upon detection of an excess flow (such as a leak), the stainless steel plates detach from the ferrite magnet and cut off the gas supply.

Application: Low pressure, High capacity fluids (N.G.). It protects systems from flow velocities greater than those anticipated under operating conditions. This means that flows from broken lines, damaged burners, etc. are severely restricted upon Magne-Flo activation. Additionally the Magne-Flo will not allow the system to resume operation until the over capacity flows have been corrected.

Operation: The Magne-Flo Excess Flow Valve (EFV) is a magnetically controlled capsule. It closes at specified flow rates, which are regulated by the flow area and magnetic strength.

Self-Regulation: A small by-pass flow is allowed (>2 SCFH) to re-establish system pressure upon closure. This by-pass is regulated at seat formation, and is extremely accurate for all Magne-Flo EFVs.
Closure Flows: The range of closure flows for the Magne-Flo EFVs are controlled by the inlet pressure to the capsule, (see attached table). The capsule activates at pressures of 50% of anticipated operational pressures of the appliance, roughly 2” to 20” W.C.

Applications:Magne-Flo EFVs will limit the accidental discharge of gas of liquids, which are: -

  • Combustible
  • Explosive
  • Toxic
  • Environmentally undesirable
  • Expensive
  • Corrosive
  • Noxious

They can also provide flow protection for surges, hose whip, line breaks, component failures, etc.

Operation: Magne-Flo EFVs contain a magnetically operated valve, which is designed to close at a specific flow rate. After closure, small by-pass flow permits automatic resetting of the valve after the flow problem has been corrected with no nuisance shutdowns.

Performance: Magne-Flo EFVs can be provided for almost any flow of fluid (gas or liquid). Some typical performance ratings for production capsules with various fluids are shown later.

Configurations: Magne-Flo EFVs comes in 28mm and reducers are used for 22mm pipes

Installation: It is recommended that the 28mm valves are fitted as close to the meter as possible to protect the gas supply.

Quality Control: Every EFV is tested for closure flow and by-pass flow. This assures that every Magne-Flo valve will operate as specified.

Summary of specifications:

Maximum operating pressure100 psig

Maximum capacity (air)700 SCFH @ 100 psig

Differential pressure (Closure Pressure)2” - 20” W.C.

By-Pass Flow (air)> 2 SCFH

Maximum Closure Flow (air)700 SCFH @ 1000 psig

Capsule Size 0.623” dia.

Installation Size Receptacle 0.625”

Primary Fluids (gas) Natural Gas

Flow Exit Diameter 0.392”


In the event of gas leak someone is responsible for the consequences.

If you smell gas call 0800 111 999Transco will come and shut off the gas. Then the supplier of gas to the home or the owner has to arrange for the fault to be rectified. This may be with the benefit of a maintenance contract. If the householder is the tenant, then the landlord may be responsible.


Are you in this chain? If so we would recommend that you fit a Magne-Flo safety shut off value sooner rather than later.

Magne-Flo Excess Flow Valves LTD

22 Brookend Drive, Henley in Arden, Warks. B95 5JA

T: 01564 782 776 F: 01564 784 896


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