There are a lot of ways you can build your engineer for support or heals. When I started out a better healer-engi gave me some advice about a build that runs 10/0/30/20/10, with backpack regenerator, self regulating defenses, and kit refinement for survivability boosts.
This is what I use for PvE Support. All the relevant details are included in this website as well (mainly what runes to get, sigils to focus on, and armor nomenclature-Cleric’s). You get ample healing from your Med Kit Bandages/Supply Crate Bandages and Regeneration Boons (Rune of Dwayna/Healing Mist) when you stack Cleric’s gear. The Elixir Gun, while pretty weak, roughly heals for ~300 HP a second in Full Exotic Gear and coupled with Kit Refinement, spawns two which doubles that to 600 HP a second (provided your allies are standing in the circle…let them know ahead of time). Your bombs will also heal for approximately ~300 HP an explosion which while not terribly efficient for healing allies, can be used to bolster your own survival. Use the bombs to control your enemies with Smoke Bomb and Glue Bomb, the Flamethrower to push/interrupt key enemy actions (when monsters charge up for example) and blind, and the pistol/shield to daze, knockback, and blind.
Edit: Bad link. Here’s another site: http://www.guildhead.com/skill-calc#mzMzM9Mz0mLNlMmGNlMa0xGaczsqmsm8kiU70z7070z7kiU707kIM70V7ofF70m8of2.
Click the Skills & Traits, Stats, and Equipment Tabs to check the information you’re looking for.
While I liked his build, I stuck with my own because of the added utility of vulnerability stacking. For PvE I run full healer & vulnerability stacking support in dungeons. If you’re interested in a tanky heals build then here it is.
I prefer healing bombs, recently its for the utility they have with regards to combo fields and blast finishers. I run 30/0/30/0/10 in full cleric with runes of dwayna, and my skills are healing turret, grenade kit, bomb kit, and elixir gun.
My build doesn’t give you the best survivability (that’s reserved for healers that max out alchemy) but it makes you tanky and gives you utility. Depending on what you tackle, you might tank with healing bombs or support with grenade vulnerability stacking. The elixir gun is just there for a cleanse, or a double super elixir in a tight spot.
The combo fields this build gives are many. Bomb kit alone gives you a fire field, a smoke field, and a blast finisher, while healing turret has a water field and elixir gun gives an air field. So how I usually synergize these together is to go bomb kit, then big ol bomb, and either smoke bomb or fire bomb. With healing turret you get the water field and blast it right away, then super elixir and shield #4 on the air field. So I end up giving my party a lot of regen, area might, lots of blow outs, area retaliation or stealth and a load of vulnerability stacking.
Last night I came back to my engineer from a guardian. Loved how maneuverable power shoes makes you in combat, decided to switch kit refinement for speedy kits, healing turret for med-kit, elixir-gun for elixir-S, and kite around for an hour. Had a blast and I noticed I survived a lot more.
As I ran I would slow champs down with glue bomb/freeze grenades, and alternate between setting down a smoke bomb (for survivability) and a combo or running around throwing grenades (and stacking vuln).
One post, three support builds which use the same gear and runes. The last two use the same traits as well, but have vastly different play styles 
heya theorycrafters
this is the build im running.
with 1 change to the actual build, healing turret instead of elixir H.
reasons, an extra aoe heal+condition clearer ( cleansing burst ) + another aoe regen ( regenerating mist ) + detonate extra blast finisher for aoe heal in water field.
cheers,
bb
(edited by Lunar Corporation.5720)