Agua Hot - symptoms for service?

[RT 41]

What are the symptoms that the Aqua Hot unit needs service
Thanks
RT41

[BigSkyBob]

Unit won't start, unit won't run, unit exhaust smokes when running, unit starts then stops, many reasons the unit is in need of service.

[TXTiger]

As a general rule you should have your Aqua Hot serviced once a year. It only costs about $200 and less if you do it yourself.

[TomAndPeg]

There are some good DIY service videos for the Aqua Hot on Youtube. Annual maintenance is a must. It's actually pretty easy and inexpensive.

[Cat320]

Originally Posted by TXTiger

As a general rule you should have your Aqua Hot serviced once a year. It only costs about $200 and less if you do it yourself.

That's what the book says. I use it an average amount and have it done every other year.

[Flanz]

Originally Posted by RT 41

What are the symptoms that the Aqua Hot unit needs service
Thanks
RT41

Once a year!!!

Change fuel filter, ~12$, and fuel nozzle ~15$. Total time, including a good cleaning, ~2hrs. This, IMHO, should be done every year to avoid downtime when you really need the Aquahot.

I’ve read numerous posts of folks asking for help fixing there Aquahot when they need it most. Typically happens during heating season.

Learn how to do it yourself NOW so that you can save big bucks later. Plenty of videos out there to help you......

[Ivylog]

The “annual” service is a fuel system service and a cleaning of the combustion chamber... new fuel filter and a new fuel atomizing nozzle regardless of the # of hours the diesel boiler has run. That doesn’t make sense to me.

I service mine when after a minute the exhaust still has a diesel smell to it. That worked out to 2 times in 14 years BUT we are half timers and half of that is in SE Fla where the electric element provides all the hot water we need...little or no boiler use. If a morning is cold, I’ll use the heat pumps to take the chill off.

When traveling during the other 3 months the engine provides enough hot water for 2 showers and when dry camping I only fire the boiler up for half an hour to take our showers. The result is less than 40 hours/year of use requiring service... times 7 years is only 280 hours. Some people may put that many hours on it in a year.

Before the advent of ULSD fuel, exercising the AHot every month for a couple minutes was probably a good idea but as clean as ULSD is I do not worry about doing it ever month anymore.

Our 08 Navigator has the 600D Ahot (2 electric elements) and when dry camping I run the generator at supper time for an hour to cook and recharge the batteries and heat hot water. SO, even when dry camping during the summer I doubt I’ll run the diesel boiler 20 hours... may have to service it every 14 years. The sniff test is a good indication of when it needs service.

[RTC1]

It works when it works. Service it at LEAST once a year. It's the absolute weakest link on our coach. Lots of boomers on here swear by it, but it is a less than ideal heating/water heating source.

[Smitty77]

I'm in the camp of yearly maintenance. And I also believe like many systems in the coach, that 'use it or lose it' approach pays dividends. I run the Diesel Burner for one full cycle, and activate the Furnace in both zones, as well as the Engine Pre Heat, which then gets all of the HydroHot pumps running. The circulation of the fluids keeps the heat exchangers fluids from stagnating and or crystalizing.

Figure I'm exercising other systems, generator, driving the coach up to temperatures, etc., etc. - so why not do the Hydro (Same as Aqua) Hot too? And, easy for me to do, as we don't need to winterize the coach.

Best to all,
Smitty

[Ivylog]

Originally Posted by Smitty77

I'm in the camp of yearly maintenance. And I also believe like many systems in the coach, that 'use it or lose it' approach pays dividends. I run the Diesel Burner for one full cycle.
Figure I'm exercising other systems, generator, driving the coach up to temperatures, etc., etc. - so why not do the Hydro (Same as Aqua) Hot too? And, easy for me to do, as we don't need to winterize the coach.
Smitty

And there’s the difference as I’ll start my engine next month after 3 months of it sitting. Same as the generator as we have not lost power this winter while snowbirding. I did use the Ahot one cold morning, partly to exercise it and the check valves which is common problem but easy to fix by tapping on them. In 14 years I never had a stuck check valve... guess my boiler fluid isn’t prone to “stagnating and or crystalizing”.

[96 Wideglide]

Originally Posted by Ivylog

In 14 years I never had a stuck check valve... guess my boiler fluid isn’t prone to “stagnating and or crystalizing”.

I haven't either. From what I have read, a lot of that issue is caused by too rich of a mixture of boiler fluid to distilled water.

[Smitty77]

Ivylog - As always, no worries in differences on how owner's approach their coaches!

I'll explain how I came about to exercising my HydroHot on a regular basis.

We bought our 04 coach, built Sept of 2003, and the 1st owner took possession end of November 2003 - in late 2010. The coach had under 13K miles on it at that time, and many a few of the systems in the coach had never been used by the 1st owner. He had bought the coach to go back and forth between San Diego and Fresno, CA - to attend Fresno State Home Football games. So the coach did get regular usage during the college ball seasons, and then was basically in storage. And according to the gent I bought it from, he had not used the coach for the previous 18 or so months, due to focusing on saving his business at the end of the 07/08 dip.

As I was doing my due diligence before purchase, I detected that the front heat register did not produce in any heat. And yet the second front living area heat registers produced heat, and the pump was running. Looking at the fluid in the overflow tank, the color was off. I asked the owner if he had change coolants, and he said 'Oh, I just put water in it when it gets a bit low. Don't use it often.' I asked did you use distilled water, and he said no, he'd get a glass out of the coaches kitchen faucets water to top it off...

I also keeping the generator running. It would start, run a bit, then shut off with an error code that indicated 'High Temp'.

Other items on my punch list of items in need of attention, were tires were OEM, Chassis battery took Boost to start the engine, and the Deka house batteries were 6 years of age. So we negotiated a bit, and I received allowances/reductions for many items at time of purchase. (The Coach was solid, and had been indoor stored for many of it's years. Yearly he had the engined serviced and I had Cummins Former Coach Care facility go thru the chassis, dyno the engine, pull fluids for engine/trans/generator... And searching the QD8000 generator posts related to '333' error code, was hoping it was a bad Temp Sensor, as the metals were not compatible and electrolysis would build up and cause the sensor to not report.).

So 'stagnation/crystallization' (Probably not an accurate term.), ended up being found doing post purchase repairs.

AquaHot - The front heat exchangers mini radiator, was clogged with the bad mix of HdroHot boiler fluid. I elected to replace the unit, vs taking a shot at cleaning it out in a radiator shop. Had the HydroHot fluid drained, and flushed, and new boiler fluid put back in.

Generator - Yes, the Temp Sensor was bad. On our coach, you have to drop generator out of the coach, as it is not in a slide. Replaced the Temp Sensor, and while it was out, replaced the fan belt and hoses and thermostat at the same time. Put the generator back in, and fired it up the unit. Yeah, we felt good, as the generator ran passed the time limit it used to shut off at, as the Temp Sensor was working and reporting an increase in temperature (The '333' code had been because the old sensor would not send a signal, so the Onan shut down assuming a problem...). We the generator run, driven both roof top AC's, as we were doing other things on the coach. After about 40 minutes, the unit shut down again, same '333' error code... ??? Opening the front access door to see the generator and get the code, I could smell the heat, and it was hot to the touch. Coolant levels looked good. We pulled the generator out again, and this time we drained he coolant, but did not get out as much as we expected. We tried flushing the generator's radiator, but no flow of fluids. Elected to pull the radiator and send it out to a radiator shop to get it in the hot tank and steamed to try and get it open again. The radiator shop said 'the coolant has crystallized' in the unit, and recommended we replace it. We did. Put the unit back together, and got it into the coach again. And we tested with AC's on for 90 minutes, and called it fixed.

----

Long story, for explaining why for all systems, I now exercise them. To keep fluids from stagnating or crystalizing...

This was root caused by lack of proper maintenance from the previous owner, but I always remember a season Country Coach Tech's comment 'Using the systems in these coaches are important. If in storage for a period of time, try to go exercise them if you can.'. And other's who I respect as I was 'Burning as I was learning!' (And luckily those burn/learning experiences have slowed down!!!), said that they felt it was important to get the tires up to temperature periodically too.

So when not traveling and using the systems, I do make it a point to try to exercise all systems, and the coach itself on a 45 min or so drive (Have a regular route my wife and I take to a great vista look out rest area, on I8 going East from San Diego, just past Alpine. Then we turn around and pull the unit back into where we store next to a rental home we have.). Just what we do, and it's been working well for us. Heck, another thing I do, is a yearly replacement of the all radiator caps (Engine/Generator/HydroHot), and I carry spares too (Rotating the stock each year.). Cheap insurance, and I did have a problem on our trip to Alaska of lost engine coolant, finally figure out it was a bad radiator cap...)

And I certainly understand that other views exist, and as mentioned earlier, those who winterize and hunker down in winter - may not be able to easily do so...

HydroHot, and ours is basically the same as the AH450 series, have lots of pumps, fluids, hoses - does not take me much time to do!

Best to you, and all,
Smitty

[Spdracr39]

I run mine once a month and service it once a year and have no issues. It only takes an hour or so and is relatively easy. The cost for parts is about 50 bucks. If you are having any kind of issue with the burner not always or ever lighting, smoking, or not staying lit until it is up to temperature the first thing to do is service it.