I wish I found some honest review before I bought it. It would save me a hassle returning it.
Thin barrel is a serious design flaw.
What I found thermal mass is insufficient, making it difficult to desolder any medium to large component.
Working with multi-layer PCBs close to impossible.
I learned after a few suctions tip's temperature may drop more then 100 deg Celsius - thermal mass too small.
Interesting
![Huh? ???](https://www.eevblog.com/forum/Smileys/default/huh.gif)
the temperature on the display doesn't drop at all, showing maximum set temperature.
It appears the sensor is not in the right spot or the firmware is ignoring it.
Another problem I found, suction tube inside the barrel gets blocked easily. it is very hard to get it cleared again.
I found the tube just before enters glass collector is exposed, not covered by heater element - another design flaw.
Wild temperature dips probably contributing to the problem too.
As far as my experience ZD8915 is an absolute lemon, so beware.
Later I had a chance to test ZD-895 and end up buying ZD-915. Both thick barrel desoldering station from the same manufacturer.
ZD-915 doesn't block as easily as ZD-8915. I found heating element covers the tube sufficiently now.
Larger thermal mass due to thick barrel makes working with multi layer boards possible.
The ZD-915 is not perfect by any means but for the price I am quite satisfied.