Originally Posted by Ka_sea_ta
I would like to add a diesel fired hydronic furnace to the boat... The boat has 3 reverse cycle ac systems each with vents to specific areas of the boat. has anyone just added heat exchangers from the hydronic furnance to the existing venting.... the heat exchangers I'm looking at have their own fan. It seems using the existing venting would simplify the installation. thoughts?
I'm guessing that you're considering using a hot water coil? If it's hydronic, it's a boiler. If it's a furnace, it's hot air. Different systems.
To use just the existing duct system would require the implementation of a damper that would essentially be a "wye valve", that would connect the duct system to whichever piece of equipment is in operation. If you have the room, it could be possible to do. It would require an interlock to prevent operation of the system that is not connected to the duct system. There would also need to be some provision to change between the systems. Automating that changeover could be challenging. It's not something that's commonly implemented, so a COTS solution would be unlikely.