Zirconia Balls

The Tempest heater comes as stock with about 80 2.5 mm diameter white Zirconia (ZrO2) balls.

These tiny balls are used for absorbing, storing heat and releasing convective hot air through the Bowl, when the user starts to inhale.
Changing the size or the type of ball material will change the heater performance: air restriction, heat absorption, heat retention, flavor profile...
Consequences for the user will be the heating time needed, the heater heat retention capacity, the optimal air stream for best vapor production and the speed of extraction.
Testing and user experience is often better than just data numbers for customizing the balance of the heater.

2.5 mm ø Zirconia gives great flavor, a slower heat absorption, enough heat retention (about 45sec) and airflow restriction (RDL).
Changing to 3 mm ø size (about 40 balls) will give the heater even less heat absorption (less surface contact) and less airflow restriction.

Stock configuration give me three optimal ways of extraction, with Mouth To Lung or Restricted Direct Lung draws:
-Half bowl one aggressive heating cycle, high temp extraction, better for consecutive fast/fresh bowls 320 to 360°C Wand timer
-Full bowl position not fully loaded, two gentle heating, easy control for low/medium temp extraction 200 to 300°C W" "
-Full bowl fully loaded, gentle multiple heating, temp stepping session extraction 250 to 320°C W" "

Using different ball media gives the user the ability to tweak the heater to their preferences, like desktop ball vaporizers.
To be fair, I didn't change them for my Tempest review, to give the stock config a better opinion, but I'll play with other ball media during the next months.

There is about 2.5mm of space between the top of the Bowl and the Ball Retaining screen inside the Cap.
Ball Retaining screen (11mm diameter) is for keeping secure the balls inside the Tempest Cap.
Using a small flat head screwdriver, the Reload Debowler rod, or the Leather case multi-tool to screw the BR screen until the end of the threads.

Be gentle, do not insist if it feels tight and take time to correctly catch the threading, without over-tightening at the end.
If the BR screen doesn't stop at the end of the threads, there are too many balls inside the Cap/Thermal matrix.

It's common sense that users should regularly check if the BR screen is still screwed to the Cap threads, particularly with heavy use, drops, shock, thermal expansion...
Threads have a slight angle, so it is normal that one side of the RB screen looks a bit bent, when correctly installed.

The online Tempest instructions suggest a ball cleaning maintenance every 300 bowls, so better to get some spare BR screen or balls, just in case.
The suggestion came from some beta users, who did get vapor condensation inside the thermal matrix, after months of intensive use.
A discoloration of the balls was observed, but a possible impact on performance still needs confirmation.

I recommend for users who don't want to deal with manipulating balls a simple cleaning method.
Instead of unloading the balls, just unscrew the top flat head to separate the Visual Indicator housing from the Cap.
The tiny screw can fall so keep it center inside the VI housing.

Remove the Induction sleeve, and soak everything in Iso, except the VI housing.
If the VI housing has any residue inside, in this case you can screw it back to the Cap and soak the entire heater.

Also, keep in mind when cleaning, that the VI spring and the click discs are more subject to flash rusting.
Dry them with a very slow, fully assembled Tempest Head heat cycle, and don't let them in a high humidity air environment for long-term storage.
Heating directly (torch or IH) the VI housing will damage your temp indicators forever.

That is why I don't recommend soaking the temp indicator parts at every cleaning.
It's possible, but tricky to replace them, so better to protect them for the long run.
For long-term storage, I use a Vitamin C effervescent tablet plastic tube, with some desiccant salt inside the lid, to store all my Tempest small spare parts.