AQUAHOT AVERAGE DIESEL USAGE EXPERIMENT

[eric@babin.com]

We normally don't sit still for very long so I was never really able to run an experiment to see how much diesel the AquaHot uses to operate furnace heat and water heater.

We showed up in Foley Alabama (just north of Gulf Shores / Gulf coast of Alabama) on November 15th.  I topped off the diesel tank just prior to parking.  Other than exercising generator a couple times and running engine for a few minutes every few weeks, I only used the diesel to operate Aquahot.  

Here are my findings:

Average temperature range in December was 44 - 62, January was 48-63 with a couple of cold snaps that lasted for a few days with lows into the very high 20's and highs in the mid 50's. 

Number of days: 75

AquaHot "burner" and "electric" on the entire time to heat water and furnace when it was needed. 

 

Total fuel usage: 100 gallons.  Distance from gas station about 22 miles each way, so about 7 of those gallons were used to drive RV and exercise generator.  Estimated AquaHot diesel usage over 75 days 93 gallons. 

 

93 gallons / 75 days = 1.24 gallons per day

 

1.24 gallons x $3.56 per gallon (today's price 1/31/22) = $4.41 per day

 

That seems like a LOT when added up for the month ($132.00).  I can't imagine what it would be in a colder climate! 

I think I'm going to turn off that burner until I absolutely need it!

 

Edited January 31, 2022 by eric@babin.com

[five]

You sure went to lots of trouble...the AH manual says it burns .4 GPH, when actually running, not just when it was turned on.  I turn mine on only if it will be used.  Normally, that is showers, only if it's cold out ant the electric can't keep up, and to take off the morning chill for the same reason.

[wildebill308]

Eric, Do you have one or two electric heating elements in your Aqua Hot? I am not living in my RV now but in December when we were out west I did run the burner in the morning to be shure there was plenty (unlimited) hot water. The rest of the time my Oasis kept everything toasty just on the electric heating elements and of course off the engine when driving. We had some nights below freezing up at the Grand Canyon and west of there.

My last RV had propane furnaces and kept it nice and warm but did like propane. I had a "extend a stay" installed to use when at some place for a while.

Bill

[manholt]

Eric, don't turn  on   engine unless you plan on driving it.  75 days is no reason to "exercise" generator!

[wayne77590]

Eric, with those temperatures you only needed to turn on the burner if you want continuous hot water, otherwise the electric will keep the aquahot going. For really cold days the burner by itself will do the job. No need to run both continuously.

As stated, no need to start the engine. It doesn't do any good for any of the other mechanical features attached to the engine such as transmission, etc. As long as your converter is keeping the batteries charge at 12.4+v, which it should, no need to start the engine.  If you must "exercise" it, you should drive it for 25 to 30 miles. During that time you could exercise the generator but it should be under a load.

p,s., owning a motorhome is not for saving money. Just sayin'.

 

Edited February 1, 2022 by wayne77590
p.s.

[five]

On 2/1/2022 at 11:07 AM, wayne77590 said:

....For really cold days the burner by itself will do the job. No need to run both continuously....


 

True, but why not run them together, and use some of the CG's electricity to help your burner that is using your diesel?  When we get to a CG, we turn on the electric, it stays on all the time, and turn on the burner as needed.

[wayne77590]

We also turn on electric when getting to the campground and burner when needed. Typically when we get up for showers having continuous hot water, then back to electric.  Haven't been in VERY cold area yet. Try to avoid cold areas and hot areas. Not successful avoiding hot areas - seems to follow us. but the 3 AC's keep us comfortable.

p.s., AH should be run for one cycle every 6 weeks to keep the nozzle clean. Good thing to exercise the pumps and heat exchangers by setting the thermostate to an operating temperature.

Edited February 3, 2022 by wayne77590
p.s.

[five]

Lloyd DeGerald, one of the AH gurus, recommends turning on the burner at least monthly, walk to the back of the MH (that's where my AH exhaust is), when the exhaust is warm, go back to the panel and shut it down, exercise over.

[wayne77590]

The guru I use is Rudy Legett. He's here in the Houston area and he is one of the teachers for the AQ system. I can guarantee you that he knows what he is talking about. So who's right. I guess it's who you might listen to.

Search on either name and you will get lots of information. 

I had to go looking. Found this which indicates a full cycle for monthly maintenance.

Monthly:
It is extremely important to check the Aqua-Hot’s antifreeze
and water heating solution to ensure it is at the proper level for
operation. This task can be done by visibly checking the coolant
level in the Aqua-Hot’s expansion tank. At maximum operating
temperature, the antifreeze and water heating solution should
be at the level marked “HOT” on the expansion tank. The
coolant level should be checked ONLY when the Aqua-Hot is
at maximum operating temperature. Therefore, this procedure
should be done immediately after the diesel-burner cycles OFF."

Edited February 6, 2022 by wayne77590
Quote from manual

[five]

I don't think there is a ''right or wrong" as long as the burner gets exercised.  I had to go looking for the procedure noted above, too...page 11, of the AH manual.  It's my understanding that when exhaust is hot, the burner has cycled off.

[wayne77590]

I'm not sure if the complete cycle needs to be performed to check the fluid. It doesn't take that long for it to cycle. Well, especially down here on the Gulf Coast.

[wildebill308]

2 minutes ago, wayne77590 said:

I'm not sure if the complete cycle needs to be performed to check the fluid. It doesn't take that long for it to cycle. Well, especially down here on the Gulf Coast.

Pretty shure if you let it run till it shuts  off  it will be at the max temp as described so you can check thee fluid. Or you could probably get buy making shure it was above the "cold" line on the  expansion tank.

Bill

[wayne77590]

Cold line doesn't always work for me so I prefer to cycle it and excercise the heat exchangers while doing it.  Also, by turning on the heat inside the coach you are exercising the two pumps for circulating the hot fluid.