Diesel Heat Consumption

[hmitchmd]

Originally Posted by TXBart

We were in overnight lows in the mid 20s and daytime highs in the mid 40s the last 2 weeks. When the outside temp hit 30 we would turn Aquahot diesel heat on and return to heat pumps when it hit ~40. Diesel Aquahot stayed on most of the day because we would forget to turn it off after showers. We drove 602 miles on a tank of fuel, pumped 106 gallons to refuel. If we got our normal MPG average of 7.4 we burned 25 gallons heating the coach. Seems a bit on the high side, we’re due for service soon.

We were in cold for 8 days with lows in the teens and highs in mid 40’s to 50. AH was on constantly for heat, hot water and heating wet bay. I ran both diesel and electric. I couldn’t tell that the needle moved at all. It burns very little.

[bevandtomH]

Dr. Mike; you have a diesel fired AH. Others with more experience may weigh in, but once a year or so should be sufficient for you.
Stuff happens as Gary can attest……
There is a parallel post showing where AH is this Fall.
We also have a fellow EC owner who is certified but is in the Alabama area.

[BluewaveRV]

Originally Posted by geordi

I realize that the boiler on the Aqua-Hot is making water for other uses, which will increase the fuel consumption, and that the room heat is delivered via registers.

Those registers might be more efficient than the forced-air, especially when there was obvious heat loss into my storage bins that I discovered when the snow melted right under the bin doors. That's a minus for me, yet the Chinesium heater still used less fuel over 10 days running continuously (and most of the time it was running flat-out to keep up the coach's internal temperature)

I've since had much of the underbody of my coach spray-foamed and I've discovered that the designers left the space between the frame rails COMPLETELY open to the atmosphere at the front and back ends... So I have closed that off (for the most part) with foam as well now. The idea is that the storage bins are supposed to be somewhat insulated, and hopefully now the air won't exchange (and my stuff get dirty) with the slightest breeze.

I had to replace my LP force air with 1 I had that has 1/3 of the BTU useable, 16K BTUs & still kept us warm @ 20 F & below outside NE of Reno. The hot H2O is heated via LP, engine, &/or 110ac. I believe that LP is less for the BTUs useable. I am trying to plumb that heavy 7.5KW diesel generator's water coolant into the engine heat circuit. I did a study in that compared a oilfired furnace like this Aqua-Hot is 80% efficient. If you burnt the diesel in the generator & recovered all the spent heat (most of it in this case) you would see a 50+% increase in useable energy/heat+electric. You would also see a cleaner burn too. Up here in the PNW LP is 1/2 the cost of diesel & if burnt right you could recover nearly 91KBTUs/gallon where just burning diesel that has 139KBYUs/gallon & at 80% or 112KBTUs useable but for the $$ 56KBTUs is what is comparison comes out to be.... Just a thought
John 1994 HR 37' DP work in progress that has no end.

[777 Driver]

Originally Posted by Dr. Mike

May I ask a side comment?

How often does the Aqua-Hot need to be serviced?
We used the Aqua-Hot maybe 3 times this year.

Best

Dr. Mike

According to Appendix E of the AquaHot Service Manual: https://drive.google.com/file/d/1DRL...ew?usp=sharing

To keep the Aqua-Hot running smoothly, it is recommended to have the diesel-burner tuned up annually. A tune-up should consist of a new fuel nozzle and fuel filter, along with a thorough cleaning of the combustion chamber. To ensure maximum diesel-burner performance, always use the recommended fuel nozzle and fuel filter when replacing these parts.

Some suggest that the amount and type of smoke that is emitted when the burner starts is an indication of the necessity for a fuel nozzle and fuel filter replacement, along with a combustion chamber cleaning (including the flame sensor). Those who follow that principle generally agree that a small puff of white smoke when the burner lights is acceptable.

Of course, you know that the burner will continue to operate flawlessly until it's some cold, dark, rainy night when the inside temperature has dropped below your DW's 0.3 degree F comfort zone spread and the electric element is unable to meet the demand. Then you'll be wishing that you had performed the 'annual' service on a nice day.

Take care,
Stu

[Ricci]

HI Dr. Mike - Service should be annual and the hours used are really not a criteria. Actually under use is not good for it as with any appliance that uses a petroleum fuel. Run it more often and things are less likely to be problematic. That diesel sitting in the lines and nozzle is not doing any good so run it. The servicing is fairly easy to learn and perform if you are at all mechanical. Just don't over torque parts as it is somewhat fragile.



Tom

[96 Wideglide]

Originally Posted by Dr. Mike

May I ask a side comment?

How often does the Aqua-Hot need to be serviced?
We used the Aqua-Hot maybe 3 times this year.

Best

Dr. Mike

Run it!

Run it at least as frequently as you exercise your generator!

If that's not possible, you may want to service it yearly.

[Rob Woz]

A gallon of Diesel has 147,000 BTU
A gallon of Propane has 91,000 BTU

I'll take an Aqua Hot over The Truma furnace/hot water system any day!

Aqua Hot system should have annual maintenance to keep it working correctly.

[Gary.Jones]

I know it as annual service, and that is what the pro service guys call it.

It should not need service more than that. What AH do you have and what service are you needing?

Gary

[brobox]

Originally Posted by Dr. Mike

May I ask a side comment?

How often does the Aqua-Hot need to be serviced?
We used the Aqua-Hot maybe 3 times this year.

Best

Dr. Mike

We travel in the summer time, so the AH is only used for hot water. I went 2 years on my 14 before servicing the AH and it was fine. I do turn the diesel on once a month just enough to heat the hot water tank. That has been enough to keep the Fuel Nozzle clean.

[mtflybox]

Originally Posted by geordi

I've got one of those chinesium diesel-air-heaters that you can buy for like $60 on fleabay...

Hahahaha... I love reading these threads.

[Dr. Mike]

Originally Posted by Gary.Jones

I know it as annual service, and that is what the pro service guys call it.

It should not need service more than that. What AH do you have and what service are you needing?

Gary

Here's the deal-
Both my wife and I practice medicine and 2020 was a nightmare (6-7 days a week, 90-100 hours a week). So, we had the idea of purchasing a coach and just getting away. We purchased the coach in April, and then Covid hit even harder. So that idea (of getting away) has been put on hold until we get back to some sort of normal.
The coach was zeroed out (all filters/fluids changed and Aqua Hot service) by the prior owner in April, 2020. The coach has about 8000 miles (almost all before we purchased it) since that service. NIRVC (Atlanta) changed the AH fluid in June and stated it did not need to be serviced.
My running thought is to bring it down to Cummins and have all of the fluids/filters changed.

Any additional thoughts would be more than welcome!


Dr. Mike

PS. The coach has the standard AH450D

[Ricci]

Hi Mike - Just to double down on what I and others said above, The coach and it's components are like your medical skills. Exercise them to stay proficient. Coaches and systems deteriorate when not used. Tires age, fuel starts to degrade and brakes rust. That holds for the AquaHot as well. Better to do preventative maintenance than road side repairs. (It's always windy, rainy and cold when a coach decides to give you trouble).


Tom

[777 Driver]

Originally Posted by 777 Driver

To keep the Aqua-Hot running smoothly, it is recommended to have the diesel-burner tuned up annually. A tune-up should consist of a new fuel nozzle and fuel filter, along with a thorough cleaning of the combustion chamber. To ensure maximum diesel-burner performance, always use the recommended fuel nozzle and fuel filter when replacing these parts.

Some suggest that the amount and type of smoke that is emitted when the burner starts is an indication of the necessity for a fuel nozzle and fuel filter replacement, along with a combustion chamber cleaning (including the flame sensor). Those who follow that principle generally agree that a small puff of white smoke when the burner lights is acceptable.

Of course, you know that the burner will continue to operate flawlessly until it's some cold, dark, rainy night when the inside temperature has dropped below your DW's 0.3 degree F comfort zone spread and the electric element is unable to meet the demand. Then you'll be wishing that you had performed the 'annual' service on a nice day.

Take care,
Stu

Originally Posted by Dr. Mike

Here's the deal-
...
The coach was zeroed out (all filters/fluids changed and Aqua Hot service) by the prior owner in April, 2020. The coach has about 8000 miles (almost all before we purchased it) since that service. NIRVC (Atlanta) changed the AH fluid in June and stated it did not need to be serviced.
My running thought is to bring it down to Cummins and have all of the fluids/filters changed.

Any additional thoughts would be more than welcome!

Hi Dr. Mike,

Thanks for your sacrifices to keep us healthy.

There's no doubt that AquaHot recommends annual service on the diesel burner. It's clearly stated in the service manual that I provided a link.

Recommended...annual.

IMHO, the worst that will happen from failing to do the service annually, particularly in a case like yours where the burner was very minimally used, is that the burner will either burn inefficiently (excess fuel consumption as evidenced by more than normal smoke) or the burner will fail to light. I really don't think there's much risk of damage by failing to perform the service annually.

If you feel that you're up to performing the annual service yourself, the parts necessary will cost you well less than $100. It's really not that hard. The Service Manual instructions are well written and clear. There are YouTube videos that show the process. If you need the service performed by a qualified tech, I'd expect the cost to double.

Take care,
Stu

[brobox]

Along with what Stu said, the fuel nozzle is $15 and $8. for the WIX filter from any Auto Parts store. I carry both should I need them. Two Entegras with minimum use on the Aqua Hot, and monthly exercise, 2 year service intervals have not been a problem for me.