Butterlfy Valve  installation instructions:

Verify that the valve is suitable for the operating specifications of the medium (installation); such as maximum operating pressure, maximum operating temperature, corrosiveness and abrasiveness, etc.

Butterfly valves can be connected to the pipeline in any position.
Before installation, the pipe must be cleaned of all dirt such as sand, gravel, dirt, welding residues, etc. Otherwise the butterfly valve and it’s gasket can be damaged.

Pipelines should be continuous. Otherwise, leakage from the joints of the pipeline, to where the butterfly valve will be connected, can damage the butterfly valve
The pipeline should be free of tension before installation commences.
Verify that the distance between the flanges, where the valve will be connected, is equal to the length of the valve body.

An adequate distance should be left between the flanges, during the installation, for fitting the valve. If the valve is placed in a tight position, the gasket of the valve can be damaged and the stem imperviousness will be affected in a negative way.
While installing the valve, the disc should put into the valve in an open position such that the valve can not run over the flange.

After the valve is placed between the flanges, the tightening of the bolts and nuts must be slowly and equally done. Careful attention must be paid to this operation so that the valve is not twisted and the valve body and flange are maintained in a parallel position. Do not over tighten the bolts as this can lead to damage (distortion) of the gasket.
In vertical installations the brackets, that will prevent the transmission of the installation weight to the valve, should be fitted first. Otherwise turning the valve on/off can could twist the valve and effect the operation.

After the installation of the valve, the centring of the disc should be done by hand to ensure that the disc is perfectly placed. Afterwards the margins of all nut connections should also be done by hand, with the help of wrench