Expansion tank height for gasifier?

[GS7]

Is there a minimum height you should have for your expansion tank above your gasifier? Problem is boiler room is under a walk down living room so ceiling is low in the boiler room. A 20 gal horizontal expansion tank is 16 inches in diameter and the floor joist bays only have about 14 inches of clearance so I'd have maybe 1 and 1\2 feet height above the boiler to place the expansion tank in the boiler room. This made me consider the garage as a location for the boiler but that could lead to insurance/code issues.

 

[ewdudley]

If it is a bladder type I believe you can put it most anywhere you like. Height makes some difference since a higher tank can use less initial pressure relative to the rest of the system, and so in some cases it can make the difference between one size tank and the next bigger size. But for a bladder tank usually convenience is the main driver. It could even be fifty feet away if that's works out best for you.