Help! Temp control has gone crazy!

[MikeB]

Setup:
-Hcigar VT75 (dna 75)
-Taifun GT II (RTA)
-3 wraps of 28ga SS 430, 3mm ID (~0.5 ohms)
-15 watts / 450f with 30 watt preheat.
-Samsung 18650 (25R)

Ok, so I just wanted to change my coil last night. Did everything like normal during the coil change, take a vape and it is nuclear hot and tastes acrid, like an electrical fire.

My Taifun GT II has a stripped screw post, so I assume that it's not making a good connection, so I just try again and put in a new coil and wick since that pair may hold that burnt taste a while. Also a 3mm ID coil is almost big enough to touch the screw posts, so I'm thinking it may be that. Either way, another new coil was put on.

Two MORE coil changes later, and it's still not working. I hook it up the Escribe and the graphs are all over the place. Really, they're all erratic. Also, now it is failing to fire sometimes saying "short".

I take it all apart, scrap the undersides of the screw posts, scrap the 510 connection and lengthen the center screw a few turns, scrape the battery cap and check the adjustment screw. Tell dna it's a new coil again, and it starts looking somewhat normal in Escribe, though it can't hit 450f at 15 watts anymore for some reason so I turn it up to 20w. Today it appears to be running normally.

Altogether, it was 1 hour and 45 minutes, and I'm totally not confident inot it or my abilities now... WHAT THE HECK HAPPENED LAST NIGHT???!!!

Also, is there a way to manually tell dna you put a new coil on? It's doesn't always auto detect, and instead fires, meaning my new coil isn't room temp anymore so I have to cool it down and try again. That's annoying.

 

[cobalt327]

You should be able to remove the atty, hit fire, reattach atty and get the NEW/SAME prompt as soon as you hit fire.

FWIW, you can go into escribe and set the initial resistance (IR) of the coil where ever you want it, then lock it.

 

[MikeB]

You should be able to remove the atty, hit fire, reattach atty and get the NEW/SAME prompt as soon as you hit fire.

FWIW, you can go into escribe and set the initial resistance (IR) of the coil where ever you want it, then lock it.

That's what I thought, but it only prompts me about half the time. Maybe not even that.

Remove atty, fire, "Check Attomizer", attach atty, fire... should prompt me, but it's only been doing so 50/50.

Is there no way in the menu to just tell it you got a new coil?

Also, I didn't realize "lock ohms" was setting the "cold ohms". That makes sense. Still, I'd rather it read the ohms so it can have an accurate baseline.

 

[MikeB]

According to @VapingBad 's post over here, connection problems are one of the most common causes of temp control issues, so probably my last ditch effort of cleaning every connection point was what fixed it. I was thinking maybe it was hooking up to Escribe, but maybe not.

My connections didn't have any obvious. Issues that I could see though. How sensitive is TC to slightly poor connections?

 

[GeorgeS]

Two things - ether your coil "tails" or the 510.

On some decks the wire has to be cut RIGHT AT the screw otherwise when the hood is put in place the tails will intermittently short out to them.

Some tanks don't work well for TC. Be it multiple transitions of the center post to finally the coil itself or some Kayfuns actually have a SPRING in the positive path that causes troubles. I have some STM clones in which the tank base does not work well for TC or well at all for anything else.

Recall that any change in resistance that is not due to the coil actually getting warmer or colder will effect TC.

Personally I'd put 8-9 spaced wraps with 2.5ID. 3 wraps seems a little but not enough.

 

[Spirometry]

I would go with more wraps, 3 isn't much of a coil. Your coil can't touch anything, drop down to 2.5mm if you have to.

Temperature control is extremely sensitive to poor connections. You want your adjustable 510 screwed in tight. Backing those screws out can sometimes cause bad connections.

If the DNA knows you have a new coil, it won't ask. Don't worry if you don't always get the message.

Put your build deck on the mod and put in a new coil. Fire it one time. Now plug in the usb and turn on atomizer analyzer. Now wick it and install any chimney or top pieces. Check atomizer analyzer again and see if the resistance changed any. After the tank is fully assembled, unplug the usb then leave the mod untouched for 15-20 minutes. Now is the time to set the power and temperature.

 

[VapingBad]

That's what I thought, but it only prompts me about half the time. Maybe not even that.

Remove atty, fire, "Check Attomizer", attach atty, fire... should prompt me, but it's only been doing so 50/50.

Is there no way in the menu to just tell it you got a new coil?

Also, I didn't realize "lock ohms" was setting the "cold ohms". That makes sense. Still, I'd rather it read the ohms so it can have an accurate baseline.

It only asks when it's not sure, when the resistances are close.

It tracks the res and board/room temp after it's been vaped and then left idle for a while to calculate the coil resistance with more accuracy, which is why locking ohms should be avoided.

ETA some great advice being given in this thread!

 

[MikeB]

Wow! Thanks, guys!

I'll need to re-read and process this all, but for starters, I think I'm going to throughly clean all my connections. Then I'm going to twist up some of my 28ga wire so I can use more wraps on my coil.

Oh, and that is really helpful information about it detecting new coils. I didn't realize it wouldn't always ask, and the fact that it recalculateshould the resting ohms is amazing and awesome.

 

[MikeB]

Put your build deck on the mod and put in a new coil. Fire it one time. Now plug in the usb and turn on atomizer analyzer. Now wick it and install any chimney or top pieces. Check atomizer analyzer again and see if the resistance changed any. After the tank is fully assembled, unplug the usb then leave the mod untouched for 15-20 minutes. Now is the time to set the power and temperature.

I think I get it, but I don't want to make any assumptions.

First, I take it this is the proper process for installing a new coil on a DNA device?

Second, what does it mean if the resistance changes after wicking and installing top pieces? Should it change any? I'm guessing not. Is there an amount of change that's ok?

Why wait to set power and temperature at the end? That's already stored in the material profile. Should I adjusted it at this time? I'm guessing so. What I've done before (once, since I just got this VT75) is just to vape while watching the analyzer and set the power just enough to hit my target temp and then add in a little head room. Is that the correct method?

 

[OhTheAgony]

Oh Mike, are you still using that puny 3 wrap coil, I thought we talked about this

You don't need to twist it so you can use more wraps by the way, you can always use more wraps if you want. The height of your resistance doesn't really matter that much when using TC, it is not a mech mod.

I think Spiro means that when the resistance changes after assembly of the tank you have shorted it which could mean you didn't cut your leads short enough. Correct me if I'm wrong please, mr. Spiro.

Of course there's no need to adjust temps & settings if they are already where you want them. Starting low and working your way up is always a good idea with a new coil though.

 

[Wackyjak]

Hi Mike
I would start over. First of all some tanks just don't do tc well. If you have a stripped screw that tanks a no go tc is very finicky about connections. I don't have a vt75 but I do have a Lavabox 75. I would let your vt75 power down (or take the battery out) just to start over. My lava didn't come with a 430 ss profile in it did you have do download it from escribe? While the 75 is off I would rebuild your tank (not the one with the bad screw). More than 3 wraps on the coil see if you can get 5-6 spaced. I use ti so I can't help you there. Cut your leads as short as you can. At that point I wick mine then put it on and let it read ohms (COLD!!!) then I lock it and finish the build. I would leave the pre-heat at default. Maybe hit the return to default setting in escribe before you start if you have to. In tc the power pretty much sets itself. I have mine limited to 40w but it never hits that if I had it set to 10 it would go over that to get what it needs to reach temp. All your connections have to be good or it just will drive you nuts. There has to be a change in the ohms when you put a tank back on for it to give you the new coil option (I don't know how many ohm difference there has to be) Putting a hot coil back on would trigger it so that might be why it asks you 50% of the time. Good luck with it.

 

[Spirometry]

I think I get it, but I don't want to make any assumptions.

First, I take it this is the proper process for installing a new coil on a DNA device

I wouldn't call it the proper process, I would call it the long version. Just some extra steps to make sure everything is right.

Second, what does it mean if the resistance changes after wicking and installing top pieces? Should it change any? I'm guessing not. Is there an amount of change that's ok?

It would mean that you have a loose connection or a short. I wouldn't want to see the resistance change more than 0.002Ω

Why wait to set power and temperature at the end? That's already stored in the material profile. Should I adjusted it at this time? I'm guessing so. What I've done before (once, since I just got this VT75) is just to vape while watching the analyzer and set the power just enough to hit my target temp and then add in a little head room. Is that the correct method?

Many people make the mistake of saving their wattage and temperature settings too early. Refinement kicks in and messes up their vape. They then go and start messing with their coil, cold resistance and tcr values when in actuality there is nothing wrong with it.

If you take your time to ensure you are mating a cold atomize to a cold mod, refinement will actually make a very little differance to your cold resistance.

Your process of watching the analyzer and setting power is pretty much the same way i do it.

 

[MikeB]

Excellent! Thanks for all the feedback. I'm going to try all this out and see if I can get it more stable.

 

[MikeB]

I wouldn't call it the proper process, I would call it the long version. Just some extra steps to make sure everything is right.

It would mean that you have a loose connection or a short. I wouldn't want to see the resistance change more than 0.002Ω
Many people make the mistake of saving their wattage and temperature settings too early. Refinement kicks in and messes up their vape. They then go and start messing with their coil, cold resistance and tcr values when in actuality there is nothing wrong with it.

If you take your time to ensure you are mating a cold atomize to a cold mod, refinement will actually make a very little differance to your cold resistance.

Your process of watching the analyzer and setting power is pretty much the same way i do it.

OK, so I cleaned all connections very throughly, until my q-tips were coming away white, and the metal was shiny.

I set the coil, making sure all connections were extra snug, and got 0.480 to 0.472 ohms through the atomizer analyzer. That's a variance of 0.008 ohms. The reading never stopped moving. Is that normal?

Then I wicked and got 0.473 to 0.467 ohms, a variance of 0.006 ohms.

Compared to the coil only, peak to peak that's a variance of .007 ohms, and from valley to valley a variance of 0.005 ohms. Something must have shifted slightly.

Then I assembled it all and got 0.473 to 0.467 ohms again, still a variance of 0.006 ohms, but no change from the wicked only state.

I started the power low, at 15 watts at 470f, with a soft preheat punch at 20 watts over 1 second. By watching the device monitor, I slowly adjusted this to 25 watts at 440f, with a hard (10.3) preheat punch at 40 watts over 1 second. This is about where I landed last time after cleaning the connections.

I'm getting a warm comfortable vape, so I guess this is a good setting. Also the device monitor is giving me a cold ohms of 0.464 ohms. That's down 0.006 ohms from the last average reading from the atomizer analyzer.

Still using the same tank, since I don't have another until the Kayfun 5 gets here. Also, I'm still using the three wrap coil. I do not intend to continue to, but I am of the mind not to change too many variables at once, so I can be sure to tell what effect each change is having.

Thoughts? Questions? Comments? Insults?

 

[VapingBad]

OK, so I cleaned all connections very throughly, until my q-tips were coming away white, and the metal was shiny.

I set the coil, making sure all connections were extra snug, and got 0.480 to 0.472 ohms through the atomizer analyzer. That's a variance of 0.008 ohms. The reading never stopped moving. Is that normal?

Then I wicked and got 0.473 to 0.467 ohms, a variance of 0.006 ohms.

Compared to the coil only, peak to peak that's a variance of .007 ohms, and from valley to valley a variance of 0.005 ohms. Something must have shifted slightly.

Then I assembled it all and got 0.473 to 0.467 ohms again, still a variance of 0.006 ohms, but no change from the wicked only state.

I started the power low, at 15 watts at 470f, with a soft preheat punch at 20 watts over 1 second. By watching the device monitor, I slowly adjusted this to 25 watts at 440f, with a hard (10.3) preheat punch at 40 watts over 1 second. This is about where I landed last time after cleaning the connections.

I'm getting a warm comfortable vape, so I guess this is a good setting. Also the device monitor is giving me a cold ohms of 0.464 ohms. That's down 0.006 ohms from the last average reading from the atomizer analyzer.

Still using the same tank, since I don't have another until the Kayfun 5 gets here. Also, I'm still using the three wrap coil. I do not intend to continue to, but I am of the mind not to change too many variables at once, so I can be sure to tell what effect each change is having.

Thoughts? Questions? Comments? Insults?

That's a lot of variance, IIRC there have been issues caused by a loose cathode screw on VT75s
HCigar VT75 Nano w/ Crown 2 - Evolv DNA Forum

 

[MikeB]

That's a lot of variance, IIRC there have been issues caused by a loose cathode screw on VT75s
HCigar VT75 Nano w/ Crown 2 - Evolv DNA Forum

Well... that's interesting.

 

[MikeB]

So, oddly enough, just after making my update post, I got my Lost Vape Therion 133 in the mail.

I throw my tank on it, and dial in the same settings, and the vape feels impossibly cool. It's reading a cold ohms of 0.464, just like the VT75, but its saying I'm at temp with only 9 watts or so, whereas I was in the 15 watt range on the VT75. I've had to dial the Therion up to 470f to get close the the vape I was before, so far as "mouth feel" goes. How can 440f on the VT75 equal 470f on the Therion 133? And they were both reading the same cold ohms. Huh? I'm so confused now.

One difference is I had to install SS 430 as a material on the VT75, where as the Therion had it preloaded. Could that be a factor?

 

[GeorgeS]

I would try closing down your air flow rather than rising the temperature set point.

That 3 wrap 28AWG coil does not have much mass or surface area to make vapor, your likely getting more fresh air in your vapor stream than vapor. Closing down the air flow to more closely match the vapor production will increase the vapor temperature at the drip tip.

Personally, I find the 'preheat' function on DNA mods in TC mode fairly to completely useless as the preheat is is also temperature controlled. If your build needs 40W to get up to temperature in a reasonable amount of time, just set the wattage to 40W and let the mod take care of the rest.
Preheat is/was really designed for power/wattage mode where a user had a large mass coil which needs more watts to get up to a usable vaping temperature but would get to hot if that wattage was continued to be used - hence the two power level "preheat" and "normal".

 

[BobC]

George, I think you're not understanding pre-heat functionality:
1.] Pre-heat works in temp control only, not power mode
2.] You set a pre-heat power limit and duration
3.] The pre-heat function 'punches' power up to the limit set, for the time set to instantly bring your coil up to the temperature limit you set

In power mode, the DNA uses power level you set, coil temperature is ignored

 

[GeorgeS]

George, I think you're not understanding pre-heat functionality:
1.] Pre-heat works in temp control only, not power mode
2.] You set a pre-heat power limit and duration
3.] The pre-heat function 'punches' power up to the limit set, for the time set to instantly bring your coil up to the temperature limit you set

In power mode, the DNA uses power level you set, coil temperature is ignored

I'm a TC only type so I never use power mode. Outside of it oddly not being available in power mode (where it would be useful) I still think it is completely worthless in TC mode.

Since both the "pre heat" and the main heat are temperature regulated, simply setting the main power setting so the coil heats up within reasonable time accomplishes the same goal without the preheat. (much like just about every other TC device)

A preheat in power mode would actually be useful.