The internal boiler system may make a clicking sound as the pump starts to engage. This is normal and should quiet once the internal pressure has been built up. If you notice a persistent clicking sound (accompanied by no steam output) check to make sure the water intake tube is fully submerged. If not, rotate steam unit or refill water tank.
Models: STEVA+ STP010 / STEAM+ SMP010 / STEAMPAC+ SMP110 / STEAM FLR SMP002