If I have two sentries out with the rune - Aid Station, which grant the players within the radius to gain life at 1%/sec will they stack to give me life at 2%/sec?

With three if they stack my DH will gain more than 1K life per sec and have 3 sentrys doing 3x 40K per sec which sure makes me not want to used the hosed down version of Shadow Power - Gloom.

Opinions/answers?

I'd be skeptical of the effect stacking. You may not be able to place them close enough to stack, anyway. If you get together 4 DH each with 3 Sentries up, they would be regenerating 12% HP / second and that doesn't seem likely. Also, don't forget that they do a percent of weapon damage, not dps and they can't crit. They do 88% of your weapon damage which is modified only by +damage and Dexterity. It's a ton lower than displayed dps. The fastest way to figure out the 1.05 damage output is just to throw one down right now in 1.04, note how much damage one puts out and multiply the non-critical hits by 1.6. That's the damage in 1.05.

Don't forget that Sentries don't move which means you'll have to kite monsters back to your Triangle of Death and wait 17 seconds to start a new one (drop one, cooldown 8 seconds drop 2nd, cooldown 8 seconds drop 3rd). It won't be particularly efficient, but it could be an absolute blast to play if you drop some caltrops to slow and have enough hatred to drop a Spike Trap occasionally, too.

I think Sentry is going to be utterly fantastic against Belial and I look forward to smashing his face in retribution for all the trouble he caused me in 1.03.

I agree with @ecocd that it's not likely for the life regen to stack. Even so, 3 sentries will give you lots of freedom to move around while still being healed. I think a team of DHs can still do really well if 1 uses aid station and 1 damage reduction.

I'm currently testing out sentry right now as well. I've asked this question on the game forum (but about the 15% damage reduction rune) and I got a few responses saying it does not stack unfortunately.

I'm using the 6 second cool down rune at the moment. I can easily get 2 together and keep elites surrounded by them. I tried using the passive that gives you the 3rd sentry, and it wasn't to difficult getting them all together..I just don't have room to actually use that engineering passive.