Shut off valves are generally installed prior to the regulator. This valve is kept in the open position meaning the gas flow is not interrupted. Sometimes the outlet pressure of the regulator increases due to accumulation of debris leading to the diaphragm in the regulator getting either stuck or sluggish. In such situation, the shut off valve is immediately turned to the off position. This is a manual operation.
It is possible that nobody maybe around to monitor the flow of gas or notice the pressure build up in the regulator. Either to prevent such a situation an OPSO unit (over pressure shut off) is fitted to the main line or it can also be fitted to the branch line. The LPG OPSO device can be fit in between the first stage and second stage. The OPSO unit is a safety device that monitors the gas pressure in the supply lines and compares the pressure to a preset measurement. In the event there is a failure of the regulator then the OPSO valve will activate automatically and shut the gas flow. When the situation of the pressure in the line is brought back to normal by venting the excess pressure then the OPSU device will automatically open the valve allowing free flow of gas. In simple terminology, the OPSO unit will reset itself.
Gas Equipment Direct is one of the most trusted distributors of gas equipment in Great Britain. They distribute OPSO and UPSO units for gas installations of only reputed brands that meet the stringent British safety standards. They have installed hundreds of OPSO units all over Britain and Ireland as several catering establishments use high-pressureappliances. The use of over pressure shut off valves is mandatory in these situations
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