For one who wants to perform Temple Service in the morning, if he has been working in the Temple all night: Pesachim 2b; Zevachim 19b-20a
For one who wants to perform Temple Service in the morning, if he already washed for terumat hadeshen after the rooster crowed that morning: Zevachim 20a-b
For one who wants to perform Temple Service at night, if he was already working at the end of the day: Zevachim 19b-20a
The fundamental reason to require re-washing is hesech hadaat, distraction from guarding one's purity: Zevachim 20b
Need one wash for entering the Beit haMikdash if he does not intend to perform a service ["biah reikanit"]: Zevachim 19b
Need one wash for entering the Beit haMikdash to perform a non-mandatory service: Zevachim 19b-20a
Need one wash again if he steps out of the Beit haMikdash: Zevachim 20b
Need one wash again if he sticks his hands out of the Beit haMikdash: Zevachim 20b
Whether liquid clay counts toward the minimum amount of water: Zevachim 22a
Whether red worms count toward the minimum amount of water: Zevachim 22a
The washing
What time in the morning the kohanim washed: Zevachim 20a-b, 21b
When the kohen who would collect the ashes raised or submerged the sink for washing, that signaled the other kohanim that the time for washing had arrived: Zevachim 21b