John, I had a chat with a tempest owner recently. He said it's basically a small compartment in the clean tank that heats up super quick due to its low volume, as it empties out it lets more clean solution in to begin heating. Hope that makes sense.
Re cleansmart , I've had a few machines over the years from them and have always been helpful , but also had a couple emails recently I've had to chase. Possibly due to the current pandemic putting a strain on staffing etc, certainly not their typical service