Originally Posted by northwestsailor
Ok, now this gets more complicated. I am planning to add a hydronic boiler to my boat and I was hoping to get the boiler to preheat the engine when and if the boiler starts first.
I am not actually going to hook up the coolant directly to the hydronic circuit but via another flat plate heat exchanger so the possibility of total loss of engine coolant is slim.
Maybe I am a bit paranoid but I want to keep different coolant systems separate but hopefully work together when they can.
Maybe a silly question but how are you going to circulate the engine coolant that is heated by your proposed hydronic boiler flat plate heat exchanger - if the engine is not running?
However, you plan on doing it - I would only suggest staying away from your engine's raw water
cooling system. Hot salty sea water can do a number on metal and other parts
. Additionally, any alterations in the raw sea water system may alter the volume of raw water
passing through your engine's system and then your rubber exhaust
hose. Reducing the flow through the engine exhaust hose most probably will lead to failure of the rubber exhaust hose and a god-awful mess in your engine compartment or other spaces that the exhaust hose passes through.
It is common to only consider the consequences of reduced raw water flow as related to engine cooling temperature (e.g. overheating) - but more or at least as sensitive is the effect of reduced raw water flow on the rubber exhaust hose of insufficient cooling of the exhaust gases.