Hi, The other day I purchased a used and in good condition Jensen 30B. I have a single page spec sheet for it. Nothing on this spec sheet suggests use of coal, to the contrary. the Model 30B info reads: width: 23'', height: 40'', depth: 30'', weight: 625 lbs, 'takes logs up to 28'' '
Then again, it does also read: "This advanced ADD-ON design solid fuel burning boiler ties into your present hot water system and will provide you with a remarkable savings in fuel costs. The Jensen Boiler has an integrated control system that regulates room temperature, system temperature, and operating pressure."
Other info is: "Standard Features"
Secondary Combustion Chamber with Bypass
Heavy Cast Iron Heat Baffles (front and rear)
Heavy Cast Iron Shaker Grate (standard)
Heavy Cast Iron Feed Door featuring Safety Pressure Flap (Fiber Rope Seal)
Removable rear Heat Plate
Heavy Cast Iron Ash Door with Exclusive Shaker Grate Locking Lug (Fiber Rope Seal)
Hot Water Temperature Control
Electrical Relay Control
37 CFM Draft Fan
Draft Fan Barometric Pressure Relief Valve
Temperature and Pressure Gauge
Silver Gray Hammer Tone Custom Painted Shroud Set
Domestic Hot Water Tank (and extra I think)
5 year limited warrant
Jensen, since 1922 A product of Jensen Metal Products, Inc. Racine, Wisconsin, 53403
If anyone has a real manual for the unit I would love to see it. I suspect that there must be some guidance about use for coal versus wood if in fact it is intended for coal as well.