The press headbox orifices require a minimum flow in order to adequately distribute
the pulp over the length of the press. At lesser flows, the pulp will tend to become
stagnant, this is visible through the sight glasses. The roll cleaning shower pump can
be used, with the hand valves under the headbox to add dilution and motivation at that
orifice. The Shower Interupt switch, locally mounted by the press, will allow the roll
cleaning shower pump to run, but stops the roll cleaning shower sequence for a
predetermined time, usually 10 minutes. This time can be used to manually flush the
plugged section with the full pump pressure.