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What are the parts of a changeover gas regulator?

What are the parts of a changeover gas regulator?

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     Changeover gas regulator with labelled parts


Close-up of manual changeover gas regulator bracket Changeover gas regulators are usually attached with screws and brackets to a wall or bulkhead.

Control lever and valve

Close-up of manual changeover gas regulator control lever and valve The lever on top of the regulator controls a valve which opens and closes to let the gas flow from either the main or reserve cylinder.

With a manual system, you turn the lever towards the cylinder that you want to use. An automatic regulator will switch itself over when the pressure in the main cylinder begins to run low.

Manual regulator body

Close-up of red propane regulator on manual changeover system The body of a manual changeover regulator is similar to that of other low pressure regulators. It houses the inner workings such as the valve, diaphragm and spring, which control the gas coming from the cylinder.

Outlet ball valve

Close-up of changeover regulator valve Also known as an isolation tap, the outlet valve is used to cut off the gas supply from the regulator. When the lever is turned to point in the same direction as the pipework, the valve opens to let gas flow. When the lever is turned to face sideways across the pipework, the valve closes and shuts off the gas.

Some valves incorporate a test point. This allows a service engineer to test the installed pipework for leaks with the aid of a pressure gauge.

Gas pigtails

Manual changeover gas regulator pigtails showing connector types Gas pigtails are short hoses that run between the regulator and the cylinders. They’re usually made of synthetic rubber or stainless steel and are the only parts of a fixed regulator that owners are allowed to change themselves. The female threads connect to the regulator and the POL connectors fit onto the cylinders.

You can fit adaptors over the pigtail nozzle if your cylinders have a different type of connection.

Automatic regulator body and indicator

Close-up of auto changeover regulator indicator An automatic changeover regulator senses when pressure in the main cylinder is running low and switches itself over to the reserve tank.

The yellow indicator points to the cylinder currently in use. The red colour in the window shows the gas level is low and this cylinder needs changing. White or green means the cylinder is full.

OPSO valve

Close-up of over pressure shut off valve on auto changeover regulator An OPSO, or over pressure shut off, valve is a safety device which under UK and European law has to be installed on changeover regulators which control four or more cylinders (at least two cylinders on each side of the regulator).
Four gas cylinders with changeover regulator These larger installations are sometimes used in household or holiday home LPG systems.

The changeover regulator controls the cylinders in pairs, and switches them over two at a time when gas starts running low on one side.

Wonkee Donkee explains how OPSO valves work
Close-up of regulator UPSO valve Some regulators also have an UPSO (under pressure shut off) valve. This works on the same principle as the OPSO valve, except that it switches off the gas supply if the pressure falls too low.

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