Zoeller basically builds 2 models, the 1/3HP model M53 and the 1/2HP model M98. The 1198 number most likely refers to the date code. If you cannot locate the model number in the same area as the date code, the 1/3HP model is about 10" tall and the 1/2HP model is about 12" tall. I would also suggest replacing your CHECK VALVE as well.