Evil merciful healer

[mehs]

The merciful healer archetype replaces your standard channel energy with a version that can only be used to heal living creatures. (Must channel positive, can't target undead). I have taken that to mean that it would replace an evil cleric's standard channel negative energy with channel positive energy. What say you forum goers?

[Kris Moonhand]

You probably should have marked this with the Pathfinder tag. Anyway, I don't think it works like that.

Willing Healer: A merciful healer must choose the Healing domain. She does not gain a second domain. If the cleric worships a deity, that deity must be one that grants the Healing domain. A merciful healer must channel positive energy.
It doesn't say that a merciful healer always channels positive, it says that they must channel positive, similarly to how they must choose a deity who grants the Healing domain. So you'd need to be a good or neutral cleric who worships a good or neutral deity. Being an evil cleric or a neutral cleric who worships an evil deity means that you are forced to choose channel negative energy.