Install Bus Heater

[Datenight]

As part of our preparations for the Bahamas trip I am installing a bus heater for use in the first part of our trip. This is a heater similar to the one in your car or truck.

It uses hot water from the cooling system piped through a flat plate heat exchanger, then a pump through separate tubing to the fan unit. The boat was pre wired and plumbed for this. All I have to do is get the hot water into the flat plate heat exchanger. To do that I plan to cut into the feed line from the engine to my water heater. The issue is I do not know which line from the engine is feed and which is return.

The engine is a Cummins 6.7. The photos show the water heater lines. One from the block and one from just below the engine heat exchanger. If anyone can tell me which is the feed to the water heater I would be most grateful.
Thanks,
Rob

 

[Lepke]

Don't know the 6.7, but most engines the hottest coolant is just before the thermostat and the return is near the suction side of the coolant pump.

 

[psneeld]

Sorry, can't help with the Cummins lines.

Thought I would offer up my setup to minimize points of leakage.

I installed a small 12V solar hot water pump and heat exchanger close to the engine to feed the water heater and bust heater. The costs were minimal and it was nice to minimize the potential engine coolant leak by separating the heaters on their own coolant loop.

Used one similar to this....

 

[jgwinks]

Run the engine for a few minutes when the water heater is cold. One hose should get warm before the other, that is the supply.

 

[Datenight]

Sorry, can't help with the Cummins lines.

Thought I would offer up my setup to minimize points of leakage.

I installed a small 12V solar hot water pump and heat exchanger close to the engine to feed the water heater and bust heater. The costs were minimal and it was nice to minimize the potential engine coolant leak by separating the heaters on their own coolant loop.

Used one similar to this....

View attachment 158326

Thanks Paul, I am using that type of heat exchanger.
Rob

 

[Datenight]

Run the engine for a few minutes when the water heater is cold. One hose should get warm before the other, that is the supply.

Good Idea JG, I will try that.

Rob