Rank 1: 5AA, heals for 25 HP/tick.
Rank 2: 5AA, heals for 30 HP/tick.
Rank 3: 5AA, heals for 35 HP/tick.
Rank 4: 5AA, heals for 40 HP/tick.
Rank 5: 5AA, heals for 45 HP/tick.
Rank 6: 5AA, heals for 55 HP/tick.
Rank 7: 5AA, heals for 65 HP/tick.
Rank 8: 5AA, heals for 75 HP/tick.
I believe each ward lasts 5 minutes, with a 30 minute recast.