As with any type of honey extraction, crystallisation can be an issue. If you have crystallised honey in Flow Frames the honey will not drain out.
If you are in an area that is prone to crystallised honey we recommend harvesting as soon as the honey is ready. Read more here on honey prone to crystallisation.
If honey has crystallised in the Flow Frames, you can either disrupt the cells in the frames by inserting the Flow Key and moving it to the harvest or open position. This will prompt the bees to remove the crystallised honey and repair the comb.
Alternatively, you can remove the Flow Frames from the super and soaked them in warm water to soften crystallised honey making it possible to harvest. Then return the Flow Frames to the hive and harvest in the usual way.
Stu talks about crystallisation and how to manage it in the first five minutes of this livestream Q&A:
To discuss crystallised honey in the Flow frames take a look at our Community Forum.