We have two HotBins for composting food waste. The idea was to have one as an active bin and use the other for maturing compost when it was full. We ended up with two half full bins that would not heat up.
Talking to a friend revealed that she had the same problem, the bin would not heat up when it got to be about half full. She solved the problem by using a corkscrew compost turning tool and even came round to do our bins!
The problem is finding the tool. If you know of a source please email us!