Strange Water Heater Manifold

[SV_Funday]

I am replacing the water heater on my sailboat. Currently it has a Force 10 11 gallon water heater. The Kuuma 11 gallon is a direct replacement, however I am not sure of the manifold coming out of the Force 10 is necessary. Has anyone seen this kind of manifold and do I need it? Please see the attached picture.

Thanks.

 

[Davidasailor26]

Hard to see what’s going where, but could it be a thermostatic mixer to prevent the output from being too hot?

 

[SV_Funday]

Thanks, Davidasailor26! I think you are correct. The replacement Kumma Water heater has a control that limits the flow of coolant to keep the water below 140 F. I can discard this once I replace the water heater.

 

[senang]

I had the same setup on my Force10 water heater. It is hooked up in such a way that it limits thermostatically the inflow from the engine coolant water into the water heater, but I have never been able to find oit the temperature setting. Have now replaced the water heater and done away with this contraption.
Water temperature is now controlled by a mixing valve on the tank hot water outlet mixing hot and cold water. Engine water heating loop is now just plain flow without restrictions.

 

[jssailem]

Water temperature is now controlled by a mixing valve on the tank hot water outlet mixing hot and cold water.

In my mind, from an engineering perspective this design is a much better structure on a sail boat.

Engine water heating loop is now just plain flow without restrictions.

This keeps the hoses carrying important cooling fluid to maintain critical engine temps as simple flow through structure. Less chance of a critical failure. Imagine the check valve or the thermostat braking. blocking the flow of coolant to and from the engine. Not only would you have a hot water failure, you could overheat your engine.

The coolant temp sensitive control valve was an interesting engineering idea that I would not want on my boat.

 

[Ron20324]

Hard to see what’s going where, but could it be a thermostatic mixer to prevent the output from being too hot?

Not the same model as mine, but is a thermostsic water tempering device. It uses less hot water, to lower the temerature. I've written about this several times before, but the beauty is in using less hot water from the tank, there is hot water on demad the next morning. My crews used to complanin about the water being scalding hot. My device is set at 38 C, and delivers 105 F . As I type, I am trying to find a houshold tempering valve because in a condo building the water leater delivers STEAMING HOT water. It is the best upgrade to my boat I've made. You are foolish to remove and throwaway such a needed device.