It's a standard 6V Evolution.
I'm with Pipes and Tim here, these guys work great but you have to use them the way they were designed. It really does take 3 separate steps, you can't 'cheat a bit' on any of them and get good results. The guys who are routinely getting good results have just modified the drill a bit but still 'hit all the bases'.
First step is 'let it run'. No draw, let the core heat. Go long at first until you learn it. You need to build up all the heat you'll need to get vaping
before you start to vape. As soon as you start to draw air the core is going to start cooling off, not heating up.
Then start a 'medium fast' draw to transfer heat up to the load. The rate has to be right or you'll draw too much heat over too long a time (cool it too much) or not get enough volume of hot air to do the job of too fast. A good rate might be say 20 seconds to fill your lungs completely? Maybe a bit less. Near the end, you should feel the heat in the exhaust, puff a bit out to see if it has vapor. This is what Tim calls a 'test puff', IMO an important measure, it separates step 2 from 3. If the test puff fails when you reach the end of your lungs, quickly exhale and keep going. If you can't make it happen in two tries, let it all cool and start again. Don't try to take a hit until you get a strong positive on the 'test puff'.
Finally, when it's finally hot enough, dump everything in your lungs (yes, even if there's some vapor there) and hit that puppy like you mean it, it's ready to run. That's step 3, but you need solid steps 1 and 2 to get there. After you've done it a few times you can start to modify your technique. But go ahead 'waste the battery' to learn.
The heat is on full time all the while of course, maybe a minute total at first?
The fact that the unit gets very hot says it's producing enough heat (used correctly), some vapor says the path is OK. You just need to learn to manage it right. Remember, this is a power hungry battery thing, it's designed to not waste battery, there's little margin for not using the heat available wisely.
It could, of course, be herb related. It has to be dry, otherwise you waste the energy drying it out rather than generating vapor. Fine grind is also a big plus.
Good luck, it will work I'm sure....I think it's safe to say we all had such problems early on, I was lucky in that Tim himself set me straight as I was 'babying' the heater. He said, 'we make tough heaters, let it run'.
Best wishes,
OF