Looking for some help understanding the hydronic heating system on a new (to me) sailboat, a 2018 Marlow 31 (with a Yanmar 3YM30AE & SD25 sail drive). I’ve owned the boat for less than a month and I’ve not had a diesel heater on any previous boat.
After working well 2 or 3 times, the Espar (D5, 12 V) failed to start up, making a weird grinding noise and emitting a hot, burning smell--so I shut it down immediately. I discovered the coolant expansion tank for the heater was completely empty, as was the expansion tank for the engine radiator (don’t know if these are directly related??). I found traces of leaking coolant just below the Espar main unit, so I’m thinking the system didn’t start because there wasn’t enough coolant. I tightened every hose clamp I could find—assuming this was the cause of the leaked coolant--and my plan is to fill both expansion tanks to the half-way point and then try starting the heater again.
Before I do that, is there anything major I’m missing here? I don’t fully understand the interactions among the two coolant systems (heater and engine) and the hot water heater....e.g., when motoring with the furnace off, does the engine heat the coolant in the heating system as well as the hot water heater? Is there a heat exchanger somewhere in the system?
If anyone can point me to an article or video that would be great. The Espar owner’s manual isn’t very helpful.
Thanks,
Matt
After working well 2 or 3 times, the Espar (D5, 12 V) failed to start up, making a weird grinding noise and emitting a hot, burning smell--so I shut it down immediately. I discovered the coolant expansion tank for the heater was completely empty, as was the expansion tank for the engine radiator (don’t know if these are directly related??). I found traces of leaking coolant just below the Espar main unit, so I’m thinking the system didn’t start because there wasn’t enough coolant. I tightened every hose clamp I could find—assuming this was the cause of the leaked coolant--and my plan is to fill both expansion tanks to the half-way point and then try starting the heater again.
Before I do that, is there anything major I’m missing here? I don’t fully understand the interactions among the two coolant systems (heater and engine) and the hot water heater....e.g., when motoring with the furnace off, does the engine heat the coolant in the heating system as well as the hot water heater? Is there a heat exchanger somewhere in the system?
If anyone can point me to an article or video that would be great. The Espar owner’s manual isn’t very helpful.
Thanks,
Matt