How does the water heater work off the engine?

[serpa4]

I have a C30.
I fired up the Volvo engine and let it idle for about 15 min (maybe 10) and had no warm water in the shower on my first outing to learn the boat. Wife not too happy.
Later the next day, with sketchy cell signal, I read that the water heater operates off the generator. I fired up the generator and turned on the Water heater button and it make hot water after 15 minutes. Wife was happy.
Now that I'm back home:
I just read the manual and see that there is a loop for Volvo engine water to the water heater and cabin heater. Why did I not have warm water the 1st time when I ran the engine? I do recall on one 50 minute trip to Boca Key at 17kts, I turned on the cabin heater at the helm by the thruster sticks and it did blow warm air. So the engine is making hot water for something.

Maybe I0-15 minutes Volvo engine idle is not enough?
Maybe the previous owner turned off engine water to heater?
I took a cold shower with the water on full hot, so I know I did wait long enough for any hot water to make to the shower head.

How does the generator make hot water? Does it's generator engine water feed the water heater or does the generator make electric for the inverter and the inverter make electric water heater element electricity?

 

[SkookumR29]

Your water heater heats water in two totally different ways.

The water heater has a 120-volt element in it similar to your water heater at home. That 120 element gets power either from shore power, or from the generator.

The water heater also has a coil running through it where coolant (hot coolant) circulates from the engine and indirectly heats the water in the water heater's tank.

It is likely that the 120 volt element heats the water faster than than the engine loop; it normally takes 10 to 20 minutes to properly warm up the engine to 180 F to 190 F and then that coil in the tank takes time to transfer BTU's to the fresh water in the tank. When not on 120 power from shore or generator, you just need to be patient.

 

[Alpina]

I have a C30.
I fired up the Volvo engine and let it idle for about 15 min (maybe 10) and had no warm water in the shower on my first outing to learn the boat. Wife not too happy.

Not nearly enough time to warm up the water in the hot water tank. My engine's not even close to being at temp (185) at that idle time so it would barely make a dent in warming up the water. What I don't know if there there is a thermostat that prevents the coolant from circulating to the hot water tank loop until the engine reaches a certain temperature.

If you want fast hot water, use the 120V option on shore or generator power.
Franco

 

[Red Raven]

I have a C30.
I fired up the Volvo engine and let it idle for about 15 min (maybe 10) and had no warm water in the shower on my first outing to learn the boat. Wife not too happy.

I’m not sure our Volvo D3-200 will ever get warm enough at idle to heat the hot water much. I have tried running it for over 30 minutes with no luck. I suspect your engine would be similar. The engine needs a load to warm up enough and even then it takes about 30 minutes to get to the point where the water is hot. It is possible to use the inverter and the 120V element but it will use a lot of battery power. Use your generator if away from shore power and the engine is cold.

Curt

 

[serpa4]

Thank you everyone. Obviously using the generator is the best way as it keeps the motor hours down.

 

[CAPTCRUNCH]

CAUTION! Just keep in mind that the hot water will be scalding hot after a day running the engine unless the heater is fitted with a mixing valve.