Journey motor aid water heater removal

RKL · 08-16-2014, 02:04 PM

Brain teaser question. Need advice on disconnecting motor aid water heater from engine coolant loop. Will bypassing the 10 gallon water heater loop that transfer heat to the water heater cause my engine to run cooler or warmer? If so, would it be noticeable? Thanks. Rkl

Journey39n · 08-16-2014, 03:49 PM

My guess is that disconnecting, may cause the engine to run slightly warmer, for a short time.

When connected, it might provide a slight bit more cooling for the engine, for a short time. But once the water tank gets up to temperature (say 150), the flow would be cut off, and no more circulation from the engine cooling system. And since the hot water tank is well insulated, it might not call for more, but once every few hours.

Unless you have a problem with leaks, not sure why you would want to disconnect??

It sure is nice to have hot water when arriving at a rainy, cool, campground, you want a shower, and you forgot to turn on the hot water heater. (been there, done that, more than once)

RKL · 08-16-2014, 05:14 PM

There is no water heater temp control valve to cut off the engine coolant lines flow to the water heater. Engine thermostat controls coolant line temp and thus the temp of the coolant in the lines determines the temp of the water in the water heater. Agree with you on the short time engine temp changes. Thks rkl

rvarner · 08-16-2014, 05:33 PM

I doubt it'll make any difference at all. I don't think the heat exchanger is big enough to matter in a 10 gal system.
Rich

tderonne · 08-16-2014, 08:49 PM

Calling it a "heat exchanger" is a bit generous....

(Back of my father-in-law's View water heater. He doesn't have Motoraid, but the "heat exchanger" is there.)

rvarner · 08-16-2014, 09:27 PM

Tim, I see what you mean :<) My hoses from the cooling system go in one side and out the other but there is insulation around the heater so, don't know what may be underneath. Seems to heat the water a little though. Have never tried a shower but probably possible in the summer LOL. Thanks for that-had a good laugh.
Rich

johnzuki · 08-17-2014, 07:17 AM

Quote:

Originally Posted by tderonne

Calling it a "heat exchanger" is a bit generous....

(Back of my father-in-law's View water heater. He doesn't have Motoraid, but the "heat exchanger" is there.)

That is all it takes to heat the water in the tank. Mine is just like that and works perfectly. The pipe is welded to the water tank, so it does heat the water. After a 50 mile trip, I always have hot water. I wouldn't even consider unhooking mine.

Wizard · 08-17-2014, 07:27 AM

I don't think you would ever notice any difference in engine temp. The heated water never gets as hot as engine temp as that could trip the T&P valve.

rvarner · 08-17-2014, 09:40 AM

Quote:

Originally Posted by johnzuki

That is all it takes to heat the water in the tank. Mine is just like that and works perfectly. The pipe is welded to the water tank, so it does heat the water. After a 50 mile trip, I always have hot water. I wouldn't even consider unhooking mine.

Maybe RKL has a leak or something.

Journey39n · 08-17-2014, 01:12 PM

Quote:

Originally Posted by rvarner

Tim, I see what you mean :<) My hoses from the cooling system go in one side and out the other but there is insulation around the heater so, don't know what may be underneath. Seems to heat the water a little though. Have never tried a shower but probably possible in the summer LOL. Thanks for that-had a good laugh.
Rich

Several times, I have forgotten to turn the hot water heater switch back on after parking for the night. Usually one of us will take a shower that night. With the motor-aid getting that water hot, we don't even notice any difference, water is more than hot enough for dishes, and shower.

But the next morning (usually me), I am in the shower, and the water never seems to get hot. Then it dawns on me, I forgot to turn on the switch. So turn on the propane, turn on the electric switch, and in 5 minutes, plenty of hot water.

For my tank, the engine coolant lines surround the bottom of the tank, and get the water plenty hot after a few hours drive.

Journey39n · 08-17-2014, 01:20 PM

Quote:

Originally Posted by RKL

Brain teaser question. Need advice on disconnecting motor aid water heater from engine coolant loop. Will bypassing the 10 gallon water heater loop that transfer heat to the water heater cause my engine to run cooler or warmer? If so, would it be noticeable? Thanks. Rkl

Another thought, I try never to drive in cold weather, since I full time, always travelling with the sun. But on my first trip south, in December, it was cold.

The hot water heater is in the far back corner of the coach, but with that motor-aid keeping the hot water tank toasty, all of those pipes in the back part of the coach were heated as well. Insulated or not, the tank warms that corner of the coach, and it is always warm on cold nights.