Example cooldown timings for this boss, to use as MRT Notes or on the Healer Ramp Helper. Write your character's name and hit Copy to display the text.
228648 is a very simple fight, the total healing required for a kill is not really high and so most guilds opt to run only three healers.
During the normal phase of the fight, the raid will take pulsing damage every so often from 465795, which gets increased by every amplifier active so the damage intake will be much higher near the end of the phase and non existent at the start. This damage on its own poses no danger but not dealing with the other mechanics that cause bigger spikes of raid-wide damage properly might leave people low enough to risk dying from the pulsing aoe.
The main thing you are assigning cooldowns to heal is 467297. Three times over the course of the phase four players will be affected by it and once they move into one of the amplifiers to clear the shield, they will do a hit of damage to everyone in the raid. You should aim to send your engulfs or ec when these breaks are happening specially near the end of the phase, to avoid deaths from the combination of this damage and the constant aoe.
Some players will also be assigned to drain the amplifiers, taking damage from 1217126. Your spot healing isn't the best but make sure you are covering these players with echo any time you are ramping so they do get healing from you. td is also a good emergency option is one of them goes dangerously low.
There is one additional mechanic capable of dealing very high raid damage during the normal phase, which is 472294. This happens when one of the 233623 finishes it's cast and blows up. This should never happen, but if it does happen you can try to salvage the raid with rewind. On most normal progress situations 233623 blowing up means a wipe.
During the intermission, the boss will go immune and your raid will have to run around the room using the amplifiers to avoid 467992, taking damage constantly while everyone has to move. As Preservation you are very good at healing on the move due to almost all your engulf combo being instant-cast spells the same as rewind, so plan ahead if you are the one assigned to save cooldowns for the intermission while other healers that aren't as mobile deal with the damage during the normal phase.
After four jumps, the boss goes back to the normal phase and you repeat the same mechanics, each time taking more damage from 465795 as more amplifiers remain active.