smoke coming out of the washing machine.hoover optima?

It sounds like you have a blockage in the pressure line, 1st with m/c disconnected and drained off lay it on its back , possibly on the filter housing you will find a rubber hose with a smaller pipe attached its that part which is blocked with limescale remove this clean out and reassemble in reverse order, the smoke was caused by the machine thinking it had water and the heater came on

Washing machine man Southampton
March 2014