The documentation from Amtrol says the tank expansion "can be mounted anywhere in the system". It makes sense, but I've always seen them in close proximity to the furnace/boiler.
I will have two tanks (gas and coil boilers in series) and would like to put the tanks about 8' from the outlets on the boilers, tucked up in the exposed beams in the ceiling. Valve w/ drain at each to allow air purge from the line. (and clean change in the event of failure)
Would this be a problem?