Aquahot 100-04S issues. No Hot Water. Thanks

[IEMan 1]

Help!

I am having an issue with my Aqua-Hot 100-04S in our 2006 Dynasty. Our electric part stopped heating the water so I checked and the fluid was empty in the reservoir. I added to that and then checked the tank itself and it was low. I added about a pint and a half through the drain hose to fill it up. Still no heating. I do not see any sign of leaking fluid anywhere.

The red light for the "Low Tank Level-Cutoff" I can not tell if it is lit up or not. If it is it is very dim. A few of my LEDs it's really hard to see if lit or not. I have continuity between pins 15 & 16 for the float switch. 

I have checked all breakers and fuses. Also the 2 reset switches on the thermostats and the reset on the controller board.

Both the "Electric Heating Element Status" & "Heating Status" lights are on. There is no DC voltage at pins 11 & 12 for the AC relay.

I am fairly new to all of this troubleshooting stuff and could use all the help I can get.

The diesel has not worked since we got the coach and I have not attempted to troubleshoot that yet. I know that the air blower does not come on at all after the diesel switch is turned on. Then the diesel light shuts off after a few seconds of no blower.

I know that they are 2 separate issues. But we are needing hot water. Any suggestions other than taking it to a shop are greatly appreciated.

[timaz996]

I don’t have your model of Aqua Hot, but I would highly suggest downloading the maintenance and troubleshooting manual for it.

[Jdw12345]

Ours quit a couple of years ago, used the trouble shooting guide and a VOM to diagnose the issue, ours was the high limit temp sensor. Use the guide that was on the link that someone sent you on Facebook. Start learning about your coach and your systems. 
 You’ll thank yourself later in your ownership. 
 

[Tom Cherry]

Odds are.  You have at least two issues.  The “hot water” system is dual “fire” as in you use 120 VAC for residential or domestic water heating.  The Diesel is used when there is a higher demand, such as “interior” heat.  NOW, everyone taking a shower and washing dishes and running laundry all SIMULTANEOUSLY….will exceed the capacity of the electric heater.  Memory….and I’d have to pull a AH manual.  The diesel burner has about 10 times the capacity of the electric coil or heater.  I  do this once a year this topic comes up….so, maybe only 5X….

OK…the hot water system does not depend on Diesel for ordinary hand washing and dishes and a shower or two….it just takes LONGER to recover and heat back up.

Therefore, download the manual.  It is on the Aquahot site, if not already in the “file” of all the component owner’s manuals that originally came with the Motor Home…if you can’t locate on the AH site…call…and they will send you a link.

Do the step by step troubleshooting guide for “NO HOT WATER”.

Next…there is another topic, similar, running.  No Diesel is the result of, 90 - 95% of the time, lack of maintenance as well as “AGE”. The burner nozzle “plugs up”. The AH trained and certified tech that does my PM says that the more you use the diesel, the longer the nozzle lasts.  When it sets for long periods of time, even though there is a filter on the diesel. It starts to gum or plug.  Now…the nozzle is not just an orifice….like on a garden hose sprayer.  It has a sintered metal passage….think tiny metal honey comb.  The fuel, under pressure, goes through this and then is atomized and is a “spray” inside the burner housing. 

Most people experience a “needs PM” condition every 2 - 4 years….and that depends on the “cleanliness” of the fuel they use.  The typical DIESEL PM is a new filter and a new nozzle and burner housing adjustment….and a thorough cleaning inside the “burner assembly”.  NO IGNITE…then there is a detailed trouble shooting guide for the electrical and electronics. The PM also includes a functional test of every zone to ensure the pumps (4 or so) work as well as the fans on the small “radiators” where the heated boiler antifreeze is circulated.

If you can use a VOM and follow the instructions….most can trouble shoot the “no hot water”.  That’s it….  Read the manual as to the “operation” and how this whole complex monster works….then tackle the NO HOT WATER.  Once fixed….then move onto Diesel….IN THAT ORDER….the “SYSTEM” or Hot Water heating HAS to work….OK, you COULD have a dead electric heater and the Diesel would work….but domestic hot water depends on the AC Heating system to work..

 

[vito.a]

Just wanted you to realize the 120v electrical side of the Aqua Hot takes 2-4 hours to heat the boiler fluid.  

[Dr4Film]

@IEMan 1

There can be a myriad of things that will cause the Aqua-Hot not to function correctly. Since this coach is new to you and came with the Aqua-Hot not working, I would STRONGLY suggest you take it to a "certified" Aqua-Hot service technician so they can go through it and do a complete service on the unit. It should cost around $300-$500 depending on where you go.

Where are you currently located?

[rockbust]

I just went through the same process troubleshooting my aqua hot. So I had no voltage on the pins to the relay. Both my lights were on. Seems to me if you have 12 volts on on your relay you can then simply check the relay and see if it's energizing and passing through the 120 volt to the heating element. I believe 120 volts comes in goes through one of those limit switches right above and then through the relay through the heating element.

[Dr4Film]

@rockbust

I am guessing that your terminology for "limit switches" is what the manual calls "High Limit Thermostats". There are two, one for the diesel control and one for the 120 VAC control. They should be normally in a closed position ALL the time unless either the diesel or the electric run "out of control" causing the High Limit Thermostat to open and shut it down.

There is only one Control Thermostat that controls both the diesel and the electric as to what temperature to turn on and what temperature to turn off.

The Electric Assist Switch on the Aqua-Hot control panel inside the coach is simply a 12 VDC switch that activates a high amp relay which then allows the 120 VAC to flow through to the electric heating element in the boiler tank.

[Venturer]

What Richard said. Our Aqua-Hot is the same model as yours and had a similar failure. I called a Mobil certified tech who came to our house and watch him open it all up. Mine turned out to be a failed high limit switch. I also had him service the burner and replace the filter. It has worked flawlessly since. I might be able to do it myself the next time, but he was good and for $500 every two years, I'll let the professional do it.   

[radioman]

If the electric status and heating status light are on you should have battery voltage on pins 11 and 12 on JP3 on the LED board. If not you have a bad board. 

 

[Jetjockey]

Get a test box from Louisville or webasto and youcan check all blower burner functions with out replacing anything.:

It is a plug and play and in the long run or short run will save you time and money. Starting to throw parts at aquahot till it works is not my chosen method.

[rockbust]

19 hours ago, radioman said:

If the electric status and heating status light are on you should have battery voltage on pins 11 and 12 on JP3 on the LED board. If not you have a bad board. 

 

Correct. My new board just arrived. 

[Grant Stanton]

Actually I have the exact same unit which I just pulled out to rebuild last winter and the electric hot water is exactly the same as an electric hot water heater in your house, as a matter a fact I went to Home Depot to get a new heating element for mine. I'm attaching a photo showing you where there is a little round door that you can take off to see if you are getting AC voltage to your element or not. So if your lights are on as you say they are, after you take the cover off, set your voltmeter to AC volts not DC and see if you are getting around 110 AC volts your element is probably burnt out. If there is voltage you can unhook the wires to it and set your meter to ohms and test for continuity and you should have approximately 10-30 ohms resistance, if you have zero then the element is burnt out and will need replacing. If thats the case it will be a good time to flush out the boiler tank real good. Good luck if you don't already have it working.