Yes it is possible to do this with 480 ivl Without the potion that cleanses the Doom dot on you ( if you struggle to kill him within the duration of it )
I did this with 482 ilvl and above in multiple Locks, with or without set bonus 2 - 4 . Just get all reforges and gems correct so you can get the most mastery and crit.
I'll explain what should be happening for each phase.
- Phase one
Fights starts , Prepot
You just got Pit Lord enslaved , you should also sit on 4 full embers just by using your normal rotation.
Use straight away Pit Lords charge and cast 3 chaos bolts. ( if you have 4set bonus you should already have popped DS while you cast CB )
Keep your normal rotation on boss with Immolate ticking and Rain of Fire falling boss will cast his 1st Chaos bolt , dodge it with Portal or Gateway, get back in melee to get yourself dispelled by Pit Lords breath , it also important to not let Boss cast multiple dots on you while you gonna use the portal - gateway cos they might get you out of position by the Seed of terrible corruption when it knocks you back, single dispel by command demon is very useful.
At this point Boss will be going in the middle and that means 1 thing and only Cataclysm is about to come in the next few seconds, meaning that your 2nd Pit Lords charge should be ready to be used. Let him cast cataclysm why you cast your own Chaos Bolt in mid cast of yours , use the Charge and dump all embers you got. He will start doting you again , repeat the dispelling steps.
He now is moving to start summon the Fel Imps , your Charge will come shortly ready anytime soon.
Imps are spawning , Rain of Fire on them this will get you full embers already , cast 1 FnB immolate and refresh RoF.
You are ember caped and charge is ready. Use Charge while casting CB , your should aim to cast 5+ chaos bolts on boss while sitting and taking fel imps down with just RoF immo and a Shadowfury to stop them casting , he got you fully doted and is about to cast Chaos Bolt get inside melee , get dispelled and get ready to Portal - Gateway. Imps should be dead and you full embers.
Boss moves to middle and gets ready to cast Cataclysm , charge and use 2 chaos bolts on him. At this points you start thinking getting dispelled by Breath and ( put Pit Lord to passive ) so he's ready to be Move in a LoS position for felhunters. dispel yourself with Command demon from now on.
- Phase two
1st comes and you pop DS and cast your 1st Chaos bolt to it followed by Conf and if not dead bring it below 20% to shadowburn it. you get 2 emebrs from it meaning you have 3+ now. 2nd Felhunter comes , use Havoc on this one and cast your 2 CBs on 3rd and shadowburn it, and 2nd is still alive , CB + shadowburn it. Boss will cast a Chaos bolt on you, Felhunters are dead , target boss and send pet in , pop you SacP and use his healing colldown on you and absorb this chaos bolt. He will have you fully doted , and you have dispelled your self so far by Command demon.
Boss will move to middle to cast Cataclysm and you have 3 if not 4 embers. Charge and dump all embers with CBs, get breath dispelled at all times from now on.
- phase three
Boss moves to summoning position and you charge should come out of cooldown soon , and you gonna dump all embers you got to that charge.
Doom lord is spawning , use Soul Shatter when he comes and get in melee to get breathed , this will loose all your aggro on Doomlord and breath will get Pit Lord aggro ( if you feel comfortable with Banishing Doomlord feel free to do so ).
When boss comes to middle you gonna use all embers you got left when you charge him.
and now boss will start moving to summoning position to get Fel Imps again , you repeat 1st phase again ( Nuke phase cos imps will generate you infinite embers to dump on boss while you charge him again )
Your doomguard should be popped around 30% because he will be 1min up and when you hit boss @ 20% he won't last more than a minute.
Your 2nd Potion should be used when boss is below 20% and you have 4embers to cast all 4 shadowburns at once, it's really important that you keep immolate ticking and RoF falling to generate you always embers.
repeat all the above actions for each phase and you will master every phase.
here are some videos of kills with the explained tactic above.