Espar Hydronic Heater Question

[Strait Shooter]

Are these types of hydronic heaters only used with FWC engines?

[Lancerbye]

No. They are not necessarily hooked up to the engines. They are mostly used to heat a number of zones, having their own liquid system as a heating medium. Some are also tied to FWC engines to provide a heat source for hot water and the engine for winter running. They were originally designed to keep diesel engines warm in trucks, tanks,and generators in the cold frozen north.

[Strait Shooter]

So if I wanted to use one on a raw water cooled boat would the system have to have it's own reservoir?

[Lancerbye]

Originally Posted by Strait Shooter

So if I wanted to use one on a raw water cooled boat would the system have to have it's own reservoir?

Yes a reservoir or head tank is used in a closed circuit system such as this.

[cwyckham]

I have a hurricane, which is also hydronic (and which I would recommend). You can have a heat exchanger to get heat from the motor, but it is optional. The heater's coolant loop is completely independent from the engine's coolant and does include it's own pump and header tank.

You'd never want to connect the two because you want to protect the integrity of the engine cooling system, and because the extra volume of coolant through the whole boat wouldn't work for the engine cooling system.

[DeepFrz]

You'd never want to connect the two because you want to protect the integrity of the engine cooling system, and because the extra volume of coolant through the whole boat wouldn't work for the engine cooling system.

Many boats do in fact connect the two via a dedicated loop that keeps the engine warm. Engine coolant isn't pumped throughout the boat but only through a heater/engine loop. Some people also run engine coolant to a separate heat exchanger to keep the inside of the boat warm while motoring. That option is only available when you have a FWC engine.

[cwyckham]

Originally Posted by DeepFrz

Many boats do in fact connect the two via a dedicated loop that keeps the engine warm. Engine coolant isn't pumped throughout the boat but only through a heater/engine loop. Some people also run engine coolant to a separate heat exchanger to keep the inside of the boat warm while motoring. That option is only available when you have a FWC engine.

Thank you for clarifying. I see my post wasn't very clear. I do have the separate heat exchanger between the engine cooling loop and the heater loop and I think it's a great idea if you have a fresh water cooled engine.