Franco Belge owners: BTU rating on FB 10-75-174?

Hoping a F-B owner might know the answer to this, or have a spec sheet or owner's manual to check.

I have an older F-B model 10-75-174 parlor stove like this one:

http://img9.imageshack.us/img9/2426/fp1075174.jpg

I'm trying to confirm the BTU rating on this or similar F-B parlor stoves. A dealer in my area told me he thought 48,000 BTU normal, 55,000 max.

Thanks!