A filter assembly comprising: a manifold having a fluid inlet and a fluid outlet, a filter housing having a filter medium provided therein, the filter medium defining an inner filter chamber and defining an outer filter chamber between the filter medium and the filter housing, the filter housing being removably attached to the manifold so as to provide a fluid flow path from the inlet into the inner filter chamber, through the filter medium into the outer chamber and out of the outlet; the filter assembly further comprising a valve assembly mounted inside the manifold, and a by-pass channel defined inside the manifold between the fluid inlet and the fluid outlet, the valve assembly comprising a valve body and a by-pass valve system and a shut off valve system, wherein the by-pass valve system comprises: a by-pass valve piston having a piston body, and a by-pass valve spring arranged to move the by-pass valve piston, in response to a pressure differential across the filter medium exceeding a predetermined value, from an open position to a by-pass position, wherein in the open position, the by-pass valve spring is biased to hold the by-pass valve piston such that the piston body blocks flow through the by-pass channel and a flow path is defined from the fluid inlet to the inner chamber via the piston, and in the by-pass position, the by-pass valve spring is compressed such that the piston body does not cover the by-pass channel, to provide a fluid flow path from the inlet to the outlet via the by-pass channel; and wherein the shut off valve system comprises: a shut off valve piston, and a shut off valve spring arranged to move the shut off valve piston, in response to removal of the filter housing from the manifold, from an open position to a shut off position, wherein in the open position, a fluid flow path is defined from the fluid inlet to the inner chamber, and in the shut off position the shut off valve spring moves the shut off valve piston to close the fluid flow path from the fluid inlet to the inner chamber and to close the flow path to the outlet. a manifold having a fluid inlet and a fluid outlet, a filter housing having a filter medium provided therein, the filter medium defining an inner filter chamber and defining an outer filter chamber between the filter medium and the filter housing, the filter housing being removably attached to the manifold so as to provide a fluid flow path from the inlet into the inner filter chamber, through the filter medium into the outer chamber and out of the outlet; the filter assembly further comprising a valve assembly mounted inside the manifold, and a by-pass channel defined inside the manifold between the fluid inlet and the fluid outlet, the valve assembly comprising a valve body and a by-pass valve system and a shut off valve system, wherein the by-pass valve system comprises: a by-pass valve piston having a piston body, and a by-pass valve spring arranged to move the by-pass valve piston, in response to a pressure differential across the filter medium exceeding a predetermined value, from an open position to a by-pass position, wherein in the open position, the by-pass valve spring is biased to hold the by-pass valve piston such that the piston body blocks flow through the by-pass channel and a flow path is defined from the fluid inlet to the inner chamber via the piston, and in the by-pass position, the by-pass valve spring is compressed such that the piston body does not cover the by-pass channel, to provide a fluid flow path from the inlet to the outlet via the by-pass channel; and a by-pass valve piston having a piston body, and a by-pass valve spring arranged to move the by-pass valve piston, in response to a pressure differential across the filter medium exceeding a predetermined value, from an open position to a by-pass position, wherein in the open position, the by-pass valve spring is biased to hold the by-pass valve piston such that the piston body blocks flow through the by-pass channel and a flow path is defined from the fluid inlet to the inner chamber via the piston, and in the by-pass position, the by-pass valve spring is compressed such that the piston body does not cover the by-pass channel, to provide a fluid flow path from the inlet to the outlet via the by-pass channel; and wherein the shut off valve system comprises: a shut off valve piston, and a shut off valve spring arranged to move the shut off valve piston, in response to removal of the filter housing from the manifold, from an open position to a shut off position, wherein in the open position, a fluid flow path is defined from the fluid inlet to the inner chamber, and in the shut off position the shut off valve spring moves the shut off valve piston to close the fluid flow path from the fluid inlet to the inner chamber and to close the flow path to the outlet. a shut off valve piston, and a shut off valve spring arranged to move the shut off valve piston, in response to removal of the filter housing from the manifold, from an open position to a shut off position, wherein in the open position, a fluid flow path is defined from the fluid inlet to the inner chamber, and in the shut off position the shut off valve spring moves the shut off valve piston to close the fluid flow path from the fluid inlet to the inner chamber and to close the flow path to the outlet.