Whats this

D. McLean

I know I've read somewhere about the device pictured, but I cannot remember for the life of me what it is. Any ideas out there? How does it work?

SWEI

Looks like a Honeywell Heat Generator.

D. McLean

Thanks! That rings a bell.

Ross_24

http://www.oldhouseweb.com/how-to-advice/gravity-hot-water-heating-continued.shtml

There's some info about 4/5ths of the way down the page.

Honeywell's "accelerated hot water heating"