Solenoid Valves

Natural Gas Solenoid Valves to EN161

Solenoid Valves for Natural Gas, Town gas or LPG (Liquid Petroleum Gas) in the UK must have the EN161 Gas Board approval and can only be fitted by a GAS SAFE REGISTERED engineer. It used to be that a GORGI Registered engineer could do this, but the law changed on 1st April 2010.

The Gas Safe Register is now the only scheme approved by HSE (Health and Safety Executive) and from April 1st 2010 CORGI cardholders can only continue as a technical service and are not legally allowed to install Gas systems or appliances. All CORGI safety certificates, cards, logos and stationary will only remain valid, issued or used until 31st March 2010. 

Gas solenoid valves are designed to cope with Natural Gas up to typically up to 250 or 500 millibar i.e. 0.25 or 0.5 bar offering almost 100% sealing and reliability. Natural Gas is an explosive and potentially hazardous dangerous gas and must be handled only by approved equipment. There are general purpose solenoid valves that will work from vacuum to 10 bar but unless they are EN161 Gas approved it is not wise to cut cost and use them in place of the correct solenoid valve as there is no guarantee the valve will offer 100% positive sealing at the very low millibar pressures of natural or town gas.

Normally Closed or Auto Reset Gas Solenoid Valves.

Auto reset or normally closed EN161 Natural Gas or Town Gas and even LPG solenoid valves are designed to open when energised and fail-safe closed upon power failure. This allows for safe Gas flow control with flow only when power is applied to the valve, any power loss to control circuits, power cuts due to loss of power supply will render the solenoid valve closed and prevent the flow of gas into the system. Never fit and try to fit a normally open gas solenoid valve as the valve can only be closed with a power supply, which is extremely hazardous and dangerous.

Manual Reset Gas Solenoid Valves

Manual Reset EN161 Gas solenoid valves are designed to control the ON/OFF flow of natural gas but with an additional safety feature of the manual reset. The solenoid valve is deigned to open only when power is supplied and the valve has been manually opened using a level or knob into the open position. The electrical power supply will only allow the gas solenoid valve to sty in the open position.

Upon power failure the manual reset gas solenoid valve will automatically close and stay closed even if electrical power is reapplied. When power is reapplied or applied for the first time the gas solenoid valve will stay closed until an engineer manually actuates the valve into the open position via the level or knob. Then and only when manually reset will the gas solenoid valve open again, and with the electrical power on will now stay in the open position.

The reason for a manual reset gas solenoid valve is basically safety, gas has the potential to explode so if there was a power cut due to system error, power supply error or control error any flame the gas was feeding will have gone out including any pilot flame. So if the main gas solenoid valve was to reopen automatically there may not be the required pilt ignition flame available to ignite the main gas feed and thus potentially the area could fill with gas. A 1 to 7 air gas mixture will explode if ignited by spark or pilot flame.

Read more about Safety shut off Gas valves here...

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