15 inch egg. Unable to hot

With your platesetter in there, you're seriously limiting the amount of airflow through the egg...  The egg shouldstill get hot enough to cook a steak indirectly, however you're going to have to be very patient.

A better option in my opinion, would be to remove the platesetter, and cook the steak directly over the fire - it will be much easier to get the egg up to temp this way. 

You can avoid 'charring' your steak if you prefer a couple of ways, either by raising your grid level up to the felt line (you can buy some aftermarket goodies to accomplish this, or just use some fire-bricks propped on the fire-ring, with the grate on top of them), or simply cooking the steak at a bit lower of a temp - 350 might be a good place to start trying - and watching them closely to avoid any charring.

Good luck.

Definitely light from the top. My guess is that's your problem right there. 

Nolaegghead is correct!  This solves your problem.  I had the same issue on my and my son's large! These grates are great.

http://www.amazon.com/Stainless-Charcoal-Grate-Upgrade-Medium/dp/B0063911HI/ref=sr_1_2?ie=UTF8&qid=1426653244&sr=8-2&keywords=high+que+grate

Here's one.....

That's the spirit!  It's really easy when you start figuring it out.  Just takes time.

IT WILL BE ABLE TO HOT!!!!

No need for the house fan though. I have a medium egg also. I use a charcoal lighter. 
I put the lighter all the way down to the grate. Put all the used lump by around it "it starts faster" then load up to the fire ring. I leave it plugged in till the flames start coming out through the new lump for a bit. 1 beer or 2 if I'm thirsty. Then I remove the starter. Close the lid, bottom vents wide open"screen shut" DW on or off. Fully open if on. The egg will do the rest. You can put your plate setter on at this time or wait till 300 or so then put on. Remember to burp yourself and the egg. Happy cooking.

Moraine said:

Yes.  That was the trick.  Temp gauge was perfect.   When we removed the plate setter then the temp went up.   Also added more coal. I will have to raise the grate.  No charred steak!   I might try to raise the plate setter to allow more air circulation.  I still used the house fan to increase air flow.  We have cooked on the lower temp but the steaks were insipid looking    The egg will cook on!

Glad you're solving your heat problem.  If you cook with a plate setter in the BGE, you are using indirect heat and will be roasting the steak. If that is what you are trying to accomplish, then raising the plate setter might be the right thing to do.  Most people want to grill their steaks and use direct heat with no plate setter.