what is the differance between a ubhb-25j21 mfea and ubhb-25j18 mfea. what size coil is in it and is a piston or txv inside.
The 21 is 21kw of heat and the 18 is 17.5kw of heat.
Both have 5 ton coil with TXV
Karst means cave. So, I search for caves.