How

Basically you just spam dual fire to dps and heal at the same time. Make sure your spell surge never caps because with burst power amp all your healing crits give you 6 spellpower. Use Rune of Protection when there is going to be a large amount of incoming damage. Use healing torrent every 8 seconds (when healing is needed) to conserve focus. Use sustain for large amount of heals when needed (spell surge for quick cast time for burst healing). Use voidspring when the raid is stacked closely or in groups. Finally, use healing salve on cd to apply the hot. Gate can be switched out for other utility spells.

Credits

This build was modified from ttyl's dual fire 2x crit proc theory build. The original build only had seven abilities and used 11 elder gems. My build added gate for interrupt and only uses 4 elder gems (you need 4 in order to have all the necessary amps).