How do coil heads work?

Coil Heads and how they work.

E-cigarette hardware manufacturers recently (2012-13) introduced replaceable coil heads to extend atomizer and clearomizer use.

Though non-rebuildable or 'disposable; clearomizers are still available, for example, the popular CE4, these are becoming less common as the industry moves to fulfill consumer demand for more economical solutions.

The premise of replaceable coil heads is the concept of replacing a single part, rather than an entire unit, thus saving consumers money.  By replacing a burnt out coil head, the consumer pays a fraction of what it would cost to replace an entire atomizer or clearomizer and obtains an essentially 'new' vaporizing device.

While it sounds simple, it is critical that you purchase the correct coil head, one designed to work with your device. Similarly, you must be sure that your atomizer or clearomizer is designed to accept a replacement coil head.

Below are three different coil head types, each designed to work with a different clearomizer. 

They are not interchangeable.

First is a long stem Top Coil Replacement Head. These are designed for clearomizers in which the coil is replaced on the TOP of the unit.

Next is a Bottom Coil Replacement  Head.  As the name implies, these are designed for clearomizers in which the replacement coil is inserted at the bottom of the unit.

Last is another  Top Coil Replacement Head. However, this one is significantly shorter than the first top coil.


All of these coils are basically the same but they will only fit on the device for which they were designed.

A coil head is simply a housing for a wick and coil element which vaporizes your eliquid. There is nothing terribly complicated about their design; they all work fundamentally the same way. 

There are differences in flavor, vapor production, etc., but this is due to the design of the coil and the coil and wick materials used.  At it's core, a coil head is a coil head.

Below you will see a deconstructed coil head.

It consists of:
1. A wick and coil bundle. This is what atomizes the liquid.
2. The base housing. This is where the wick and coil sit and where the coil wire connects to the negative (outside shell) and the positive (battery pin)
3. The stem or "flute." This piece seals the coil head to the top of the clearomizer so no liquid gets into it.  It also channels the resultant vapor up to the drip tip. On a bottom coil clearomizer, this slides into a center post but serves the same purpose.
4. A seal (also referred to as a grommet, o-ring or 'condom').  This works with the stem to help prevent excess liquid from flowing into the coil or the center stems of your clearomizers.

All these pieces come together, comprising an atomizer. When you press the power button, the battery sends an electrical current through the positive and negative leads of the device, flowing through and heating the connecting coil wire.  The liquid that has traveled up through the wick (through capillary or 'wicking' action) heats up and vaporizes. The vapor rises through the center post to your drip tip, and voila! 

It really is a simple system.

There are a few potential areas for problems to arise:

1. The seal is very important to it's operation, without the seal properly in place excess liquid can get into the coil causing leaks, gurgling and a host of other issues.

2. The wick, if the wick gets burned it will no longer function properly giving you dry burned hits, lack of vapor and "nasty" flavors. You must replace the coil head if any of this occurs, there is no fixing it beyond replacing the wick, some people can and do do this but it is vastly easier to just pop on a spare.

See below for what a burned and clean wick look like. The burned wick happens eventually to every coil, there is no preventing this. Wicks burn for multiple reasons:

1. The voltage/wattage is too high for the ohm of the coil generating excess heat burning and carmelizing the liquid onto the coil and creating a situation where the wick can no longer bring enough liquid to the coil, this will "pile up" and cause even more burning. Too high a voltage or wattage can actually "pop" a coil, breking it and severaing the coinnection. If your coil produces NO vapor, you've popped a coil.

2. Chain vaping, a chain vaper does not give enough time in between vapes to "cool down" the coil thus creating too much heat even with the right voltage combination.

3. Thick liquids. Thicker liquids can cause less wicking as the thicker the liquid the harder the wick has to work, delivering less liquid to the coil in turn, burning the wick.

4. Harsh liquids or liquids with sugars. Sugars carmelize much faster, sweeter liquids can easily clog a coil. Tobaccos can do the same thing.

Coil heads are sensitive, and it is for this reason most vendors do not warranty them. We cannot know what the exact cause of your "bad" coil maybe. With all of the new variable voltage and variable wattage devices out there it is very easy to pop a 1.8 coil with a high setting on your mod.

Coil Leaking:

Another issue that arises with coils is leaking and that is generally caused by sealing issues.  See below for an exanple of an improper seal.

There are usually a few seals (or o-rings) on a clearomizer coil head. These seals prevent liquid from seeping into the base or out of the clearomizer. Once the seal is damaged, it will leak.  This is no different that a seal on an oil pan: without a proper seal, you have an oil leak :/