How to determine Furnace model?

[JeffBert]

My furnace is behind a grill that won’t come out without a lot of damage and all I’m after was is what size it is.

Is there a way to determine the size? It’s likely either a Suburban SF-30FQ or SF-35FQ but I can’t read label even with my horoscope.

[bikendan]

Moved thread from the General Community Discussion section to the Appliances and Electronics sub-forum since the OP's questions are specific to Appliances and not general community questions.