Hydronic distribution manifolds are most often mounted in a lower level of a residence, typically near the boiler or other heat source. When the heat emitter circuits are located on that same level or happen to be lower level in-floor radiant loops, the manifold is typically wall mounted with the tubing connections going downward. For installations where the heat emitters are above the manifold, for example with staple-up radiant floor loops or radiant panels located throughout the upper levels of a residence, it makes a lot of sense to have the manifold "inverted", meaning the tubing connections go upward from the manifold.
A Caleffi manifold can be field-modified to be inverted and in doing so, the air vent assemblies must be turned around so air can vent out the tops. The flow meters on Caleffi's 668S1A are spring-opposed so it's no problem to have those mounted upside down. Also, for individual loop control, the Caleffi 6564 Series low current draw thermo-electric actuator is hermetically sealed so it can be mounted upside down.
For those installations where the heat emitters are above the manifold, save big time and installation costs by ordering the Caleffi manifold "inverted". We don't charge extra to do this, just specify "inverted" on the order and we'll build it ready to install with the tubing connections upward. Check out Bob "Hot Rod" Rohr's short video on the topic!
Call me if you have any questions about this! Thanks for reading...Kevin