JustFog Q16, filling, switching on and troubleshooting

Sometimes a tight-draw kit stays silent under your thumb, or the e-liquid ends up in the drip tip instead of the tank. On the JustFog Q16, these small frustrations often come down to one step nobody explained, because the manual is a handful of pictures and shop listings mostly talk about battery life. Filling, switching on, adjusting and changing the coil each follow their own logic, and each has its traps.

JustFog Q16, the four things to know

On the maker’s website, the JustFog Q16 now comes as the Q16 Pro, the Q16 FF and the Q16 Pro Plus. This guide covers the Q16 Pro, a kit pairing a 900 mAh battery with a 1.9 ml tank, and points out where the FF differs. The Pro switches on and off with four presses of the fire button within two seconds.

E-liquid goes in, with the cap unscrewed, through the two side holes and never through the central opening. The coil, 1.2 or 1.6 ohm, screws into the base of the tank, and a second button sets the voltage across four levels, from 3.5 to 4.4 V. When something goes wrong, these four steps are where checking starts.

Filling the tank without hitting the chimney

The Q16 Pro tank fills from the top. Unscrew the top cap, which takes the drip tip with it, and you will see three openings, two holes at the sides and one in the centre.

The central opening is the top of the chimney, the channel that carries vapour up to the drip tip. E-liquid poured in there never reaches the tank, it lands on the coil and eventually comes back out, through the air inlets or the mouthpiece. JustFog says so on its product page, the bottle goes over the two side holes, and only those.

UK rules come into play here too. Regulation 36 of the Tobacco and Related Products Regulations 2016 limits a refillable tank to 2 ml and requires refilling without leakage, one accepted route being a bottle nozzle at least 9 mm long that is narrower than the tank’s opening. The Q16 Pro holds 1.9 ml, and JustFog’s catalogue lists an anti-leak mechanism on the fill hole.

Once the cap is back on, let the cotton soak for a few minutes before the first puff, especially with a new coil. A wick that is still dry at its core burns on the very first firing.

Switching on the JustFog Q16 and setting the voltage

The Q16 Pro has no screen. Everything goes through two buttons and the colour of the lights, three conventions worth knowing.

Switching on and off

Four quick presses of the fire button, within two seconds, switch the kit on. The same sequence switches it off, for instance before it goes into a pocket, so that an accidental press does not fire the coil.

Choosing one of the four levels

The second button, next to a row of four lights, steps through four voltages, 3.5, 3.8, 4.1 and 4.4 V. One light lit means the first level, four lights the last.

JustFog describes the output as constant voltage, held steady whatever the state of the battery, so the flavour does not drift as the charge runs down. The right setting is found by starting on the first level and going up one step at a time until the vapour is warm and clean. An acrid taste means it is time to step back down.

Reading the battery light

The fire button light changes colour as the battery drains. The Q16 Pro product page does not give the threshold for each colour, while the Q16 FF page does, white from 100 to 65%, blue from 65 to 30%, red below 30%. The Pro charges through a micro-USB cable, the FF through USB-C.

Changing the coil on the JustFog Q16

JustFog’s catalogue calls the Q16 Pro coil an “OCC Bottom Coil”, a cotton-wicked coil sitting at the bottom of the tank. It comes in two resistances, easy to tell apart at a glance.

Spotting the right resistance

A red ring marks the 1.2 ohm, a black ring the 1.6 ohm. JustFog rates both for 3.2 to 4.4 V, a range that covers the kit’s four levels. Since the power delivered depends on the resistance fitted, the 1.2 ohm runs slightly warmer than the 1.6 ohm on the same level.

Taking it apart and putting it back

Change the coil with the tank empty, or nearly so. Unscrew the tank from its base, unscrew the old coil, screw the new one in its place, then screw the tank back onto the base, following the three steps JustFog illustrates. A few drops on the exposed cotton before reassembly help the wick soak through.

The Q16 FF is different

The Q16 FF uses another coil, a vertical one, the FF 1.2 ohm, which JustFog rates at 10 to 16 W and which the kit drives at 9, 11 or 13 W. It is changed by unscrewing the bottom cap of the tank.

When the JustFog Q16 will not fire or loses flavour

Before writing the battery off, a few checks are worth making, in this order and without any tools.

The kit does not respond

It may simply be switched off, and four quick presses will wake it. If it stays silent, charge it, then unscrew the tank and wipe the threads on both sides, as a dirty contact can stop the coil firing. Check too that the coil is screwed fully home. The Q16 Pro’s electronics include several protections, among them short-circuit protection, designed to cut the power if the assembly is faulty.

The flavour fades or burns

Look at the level first. Below the coil’s wicking holes, the wick no longer gets enough e-liquid and the taste turns burnt. If the tank is full, drop one voltage level. A taste that stays dull or acrid after both corrections points to a worn coil, due for replacement.

E-liquid in the drip tip

E-liquid poured into the central opening, a cap not screwed down properly or condensation built up in the drip tip are the first things to check. The causes of spitback, set out one by one for the Aspire Nautilus and liquid in the mouthpiece, apply to most mouth-to-lung tanks, the Q16 Pro included.

JustFog Q16 and Q16 Pro, two separate notifications

The Q16 name covers several products, and their notifications tell them apart. As JustFog’s support page points out, the Tobacco Products Directive requires manufacturers and importers to submit key information on each electronic cigarette, and the brand publishes its own list, with each product’s EC-ID, notification date and the countries notified.

The original Q16 appears under two entries, the Q16(C) kit, EC-ID 00692-16-00018, and the Q16 clearomizer, 00692-16-00016, both notified on 17 November 2016. The Q16 Pro has three, the kit, the battery and the tank, notified on 25 January 2019 as 00692-19-00057, 00692-19-00055 and 00692-19-00054. Both generations list the UK, written GB or UK, among the countries notified.

These are notification dates, not launch dates. They do show that the Pro was declared as a product in its own right. JustFog’s website carries no specification sheet for the original Q16, so whether coils cross over between the two generations cannot be checked with the maker. Read the model name on the tank before ordering coils.

FAQ

A few more questions, often asked about the Q16 and left aside above.

What e-liquid suits the JustFog Q16?

The Q16 Pro product page sets neither a ratio nor a nicotine strength. Coils of 1.2 and 1.6 ohm run at low voltage generally get on with a thinner, PG-rich e-liquid that the cotton soaks up easily. A very VG-heavy e-liquid risks wicking too slowly. Nicotine e-liquid is capped at 20 mg/ml in the UK.

Can the glass on the Q16 Pro be replaced?

No. JustFog states on the kit page that the glass tube is not replaceable. A cracked glass therefore means replacing the tank, which the maker notified as a separate product, while the battery remains usable.

Does the Q16 FF fill the same way as the Q16 Pro?

No. On the Q16 FF, turn the top part of the tank to the right until a horizontal slit appears, inject the e-liquid through that slit, then turn it to the left to close.

Can another tank go on the Q16 battery?

JustFog’s catalogue gives the battery a 510 thread, so another 510 tank will screw on, but anything wider than the 16.5 mm battery body will overhang it. A tight-draw tank with a high-resistance coil remains the most consistent match for a battery set between 3.5 and 4.4 V.

What is in the Q16 Pro box?

According to the maker’s page, the battery, the tank, a USB cable and a manual. Replacement coils are sold separately, in 1.2 or 1.6 ohm.

JustFog Q16, few settings and precise habits

The Q16 Pro leaves little to adjust, one voltage out of four, one coil out of two, one airflow setting. That simplicity shifts attention to the habits, pouring in the right place, letting the cotton soak, keeping the contacts clean, and that is where the frustrations described above are decided.

The same care applies to every mouth-to-lung tank, from filling to cleaning. Taken one at a time, these habits are enough for the JustFog Q16 to deliver what it was designed for, a tight draw with a clear flavour.

In the same nook

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L’Alcôve Feutrée is written for adult readers only. Vaping products usually contain nicotine, which is addictive, and nicotine vaping products are not for sale to anyone under 18 in the UK. This piece describes equipment and is not a buying recommendation.