Musnad Ahmad 962:81

Yazid narrated to us, Hammad ibn Salamah informed us, from ‘Amr ibn Dinar, from Sumay’, from Abu Umamah: That the Messenger of Allah (peace and blessings of Allah be upon him) performed ablution (wudu), so he washed his hands three times, three times. He rinsed his mouth and inhaled water into his nose three times, three times. And he performed the ablution three times, three times.