13Using the surface units.Troubleshooting TipsInstallation InstructionsCustomer ServiceOperating InstructionsSafety InformationHow to SetPush the knob in and turn in either direction to thesetting you want.At bothOFF andHI the controlclicks into position. Youmay hear slightclicking sounds during cooking,indicating the control is keeping the power level you set.Be sure you turn the control knob toOFF when you finish cooking.Wok CookingWe recommend that you use only a flat-bottomed wok. They areavailable at your local retail store.Do not use woks that have support rings. Use of thesetypes of woks, with or without the ring in place, can bedangerous. Placing the ring over the surface unit willcause a build-up of heat that will damage the porcelaincooktop. Do not try to use such woks without the ring.You could be seriously burned if the wok tipped over.