This is an indicator that your bottom indicator needs to be properly adjusted. Use a fingernail to hold the bottom while you loosen the inner screw 1/4 turn at a time to extend the pin until it is solidly making contact and as reliably transmitting power as with no insulator installed.
The PTFE heat shield will prevent burns, and it there are serious disadvantages to going without it: the hot stainless steel core will be exposed, it will be very easy for the top cap and mouth piece to fall out/off the Hercules without them installed. It is not possible to install the Nibbler XL without the heatshield and O-ringed "mouthpiece" replacement.
Thanks. I just got my Hercules and I found the connection was really difficult to get stable with the PTFE on. The vaporizer would keep saying Check Atomizer and have the ohms not show up, and then I would twist it a bit and it would work for a little while, and then the connection would be loose again, which was frustrating. Looking at the diagnostics, I tried to remove the two PTFE pieces besides the mouthpiece and the connection appears to remain very stable and it was hitting well, so I left them off. But I'll try adjusting the bottom connector on the bottom PTFE insulator as you suggest and re-installing, and see if I can get the same good results with the safety of the heatshield.
Although, I'll say, it really doesn't appear to be getting that hot, and I wouldn't touch the metal core with my bare hands anyway. Perhaps mine isn't getting overly hot because of the vaporizer I'm using which seems to sometmes stop and tell you "Too hot! Please wait 10 seconds" when it gets too hot according to its own diagnostics. This is NOT on temperature control, incidentally, but on the regular Wattage mode (I've just been running at 35 watts), as I tried the TC and it didn't work, I'm assuming because the TC for the digital vaporizers for nicotine generally only have settings to work with wire of T1 or Ni200, not the thick coils of T2 that the Hercules uses.
In any event, I've been happy with the Hercules despite the connection problem and I'll try the fix you suggest. But the only problem I've seen with going shieldless thus far has been the issue you note with the mouthpiece occasionally coming off the top and needing to be re-set. The top-cap has been pretty stable, and I make sure not to touch the atomizer, and I think the digital vaporizer I'm using has safety features that prevent it from getting extremely hot anyway, unless I'm misunderstanding.
Thanks for the info, especially the fact that XL won't install without the shield (another good reason to try to adjust the bottom insulator and re-install the shield!)
Just have also been wondering a little bit on technique, if anyone can help-- what's the optimal pulse length? And how long to pulse initially before the first hit? No idea at all what I'm doing here, though it's been working fine just pulsing for random increments.
Edit: actually, it's not connecting at all for me with the bottom insulator attached now. I'm going to try adjusting the centerpin again, but no luck yet.