This Chofu model is a precision built wood-burning water heater designed specifically for hot tubs. It circulates water using the principal of thermosiphon (the pumping action created by rising hot water), eliminating the need for a circulating pump or electricity. This unique feature opens up a whole new range of possibilities for alternative hot tubs. Now you can have a basic soaking tub without pumps, chemicals, or high maintenance. With the Chofu heater you can retrofit an existing tub or put together a low-cost soaking tub, using a wooden tub or stock tank.
The stove body of the Chofu is made with high quality stainless steel, grade (316), so it can be used outside, without worry. And since the firebox is also made of stainless steel, it will withstand years of service without danger of burning-out. The smoke outlet on the Chofu features a unique vented collar that provides secondary combustion of unburned gases, for reducing smoke emissions and chimney sparks.
The Chofu utilizes a sophisticated heat exchange design for efficient water heating. The stainless steel stove body surrounding the firebox is a double-walled water-jacket with a 1-inch space between, making the entire firebox (except the front) a heat-transferring surface. Additional heat transfer takes place in a water-filled baffle plate that runs horizontally through the firebox. The baffle deflects the path of the fire, so it gives up more heat into the water jacket before going up the chimney.
OPERATION The Chofu operates like a conventional wood stove, achieving its fastest heating rate from dry hardwoods. It uses 17-inch wood with an 18-inch x 14-inch x 14-inch firebox. The most efficient heating comes from using 17-inch x 1 1/2-inch x 1 1/2-inch wood, loaded at 45 min. intervals.
The Chofu has a high and low speed draft control to regulate the heating rate. It operates with the draft wide open for fast heating, and closed down to maintain temperature once the water is hot.
HEATING RATE INFORMATION Although the heating rate is variable depending on dryness of wood, frequency of loading, etc., the average heat output of the Chofu CHS is 32,000 BTU’s. A 200-gallon tub can be heated at approx. 20?F per hour.
Note: The heat output of the Chofu increases after an initial 45-min. warm-up period that heats the stove body and establishes a bed of coals.
LONG SHANK The Chofu heater comes with through-wall ports for walls 3/8" thick or less. If your tub walls are thicker, you will need the Long Shank, item #HW14163.
Chofu Wood Fired Water Heater 
