Abu Haya reported,
I saw Ali 
perform ablution, and he described his entire ablution, washing each part three times. Then he wiped his head and washed his feet up to the ankles, then said, "I simply wanted to show you how the Messenger of Allah ﷺ performed his ablution."
Abu Dawud 116
Sahihحدثنا مسدد وأبو توبة قالا حدثنا أبو الأحوص ح و حدثنا عمرو بن عون أخبرنا أبو الأحوص عن أبي إسحق
عن أبي حية قال
رأيت عليا رضي الله عنه توضأ فذكر وضوءه كله ثلاثا ثلاثا قال ثم مسح رأسه ثم غسل رجليه إلى الكعبين ثم قال إنما أحببت أن أريكم طهور رسول الله ﷺ
Grading, sahih. Tirmidhi reported it in the chapter on purification, section on what has been said about the Prophet's ﷺ ablution and how it was performed, hadith no. 48, and Nasai, hadith no. 96, 115, from the hadith of Abu Ahwas, through this same chain. Tirmidhi said, This hadith is hasan sahih, and the hadith has many corroborating narrations.