Aqua Hot stopped working

[Hobdendw]

Please help 'O wise Forum contributors:
Is there any troubleshooting literature out there for the Aqua Hot system? I couldn't find anything in the Alpine Coach Association Tech Library. Also didn't find much on the iRV2.com forums when I use keywords "aqua hot" or hydro hot".

I have my coach in the driveway on 50 amp power and have had the aqua hot running (with the electric switch turned on) and the thermostat set at ~50 degrees for a couple weeks now because of the extremely cold weather recently here in Colorado. I have checked the coach every couple days and it has been staying warm inside and you can feel and also hear the registers putting out a little warm air… just enough to keep things from freezing. However, it has been super cold here for the last day or two, so I went to check on the coach and didn't hear the registers putting out any air at all and it was unusually cold inside. I turned on the diesel switch but it only started briefly and then shut down. :bang head:

I checked all the usual stuff;
1) Xantrex panel shows power all normal… batteries charging normally and on Float
2) I turned off the master switch at the front steps and the one in the battery compartment, then turned them back on hoping it would reset something.
3) I checked all the breakers under the bathroom sink… even turned off and on the main breaker and the one marked aqua hot.
4) I checked the LED lights on the panel above the aqua hot in the basement and nothing unusual is on… just the Diesel and the Electric LEDs (because I had both on at this time)
5) I drained a little fuel out of the aqua hot filter (located by the front left leveling jack next to the huge propane tank) which is just dead weight in my opinion… but that's another thread. Aqua Hot still won't start.

BTW - I don't think it matters with regard to my current problem, but I did winterize the coach by blowing air through the lines while I turned on all the faucets, toilet, etc., and then I let the pump suck in about 8 gallons of the RV antifreeze, again while opening all the faucets, toilet, etc. Although most of the RV antifreeze was used up because I couldn't get the washer/dryer to stop cycling while I was winterizing.

Also, I replaced all the coach batteries (8 ea) at Quartzite last year, but I didn't replace the two chassis batteries. Could that be my problem? Again, the Aqua Hot LED panel has a LED that is labeled "Low Voltage" I think, but it is not on.

Please help! Is there a Reset switch somewhere? What else can I check?

[JLMunsil]

You can get the manual by going to Aqua-Hot.com.
The electric element won't keep up with the cold when its below 30 degrees.
Make sure your fuel tank level is above 1/4 full. The diesel burner won't work if it's below that.
Turn the the diesel switch off for 30 sec. than back on that will reset the panel, same as pushing the little reset button on the panel. ( This is usually for reseting a low voltage fault. Don"t know what else it will reset.)
Check the batteries for voltage
Sounds like it might be a fuel issue.

[kraig]

There is great website if type in Roger Berke Aqua Hot. Roger has a forum with free support. He also has a premium area. Roger has helped me out several times over the last couple of years with parts, service and support.

[EngineerMike]

I think on the 05 coaches the HHot needs the rest switch on the panel for reset (my 06 did). The rocker switch reset feature came in the 08-09 model year rigs

[Wil Rathke]

If reseting the low voltage reset does not solve your problem check this. I have had a similar problem. If the burner fan runs but the burner will not light, check the high temp sensor. Remove the cover and you will find it above and to the right of the burner. It has two wires and a reset switch in the center. Try pressing it if it appears popped out. I have bypassed mine because it seemed intermittent. I had mine serviced early last year and the tech left a bypass jumper wire for me to try.

[Hobdendw]

**UPDATE**
It's working this morning!
I left the Diesel switch on overnight and when I checked the coach this morning the Aqua Hot was running and it was nice and warm inside because I had left the thermostat on 70 degrees for both zones.
I don't understand why it just started working, but I'm certainly relieved. Makes me realize I need to understand the system better in case there are other problems in the future.

Thanks JLMunsil for your reply late last night. I did look at the LED panel (located in the bay with the Aqua Hot) closely last night and noticed a hole that almost looks like an LED is missing, and it was labeled something like "Low Voltage Reset". So I used a stiff piece of wire to poke around inside that hole, but it felt like there was no button inside or anything to press... Anyway, nothing changed last night after trying that, so I just turned on the Diesel switch again and went to bed. BTW, I think the model I have is the 450DE.

Does anyone think it matters if you have the "diesel" and "electric"
switches turned on at the same time? Could that be part of the problem? I did have them both on for quite awhile last night when I was checking things out.

At one point, I even set the thermostat for "Heat Pump" just to see if the Air Conditioners would try to blow a little warm air... I sat there for 15 minutes and they never came on, but I chalked that up to being because the AC shrouds were partially covered with snow and the heating elements probably need longer than 15 minutes to heat up in the extreme cold. I considered it unrelated to the Aqua Hot issue.

If the outside temperature is below 30 degrees, and the Aqua Hot "electric" switch is on, is it normal for the system to not even try to to come on? I can understand it not being able to keep up... but one would think it should at least blow some cool air.

Anyway, many thanks also to kraig, Engineer Mike, and Wil Rathke for their comments from this morning. If anything else develops, I will post again.

[Hobdendw]

Originally Posted by JLMunsil

You can get the manual by going to Aqua-Hot.com.
The electric element won't keep up with the cold when its below 30 degrees.
Make sure your fuel tank level is above 1/4 full. The diesel burner won't work if it's below that.
Turn the the diesel switch off for 30 sec. than back on that will reset the panel, same as pushing the little reset button on the panel. ( This is usually for reseting a low voltage fault. Don"t know what else it will reset.)
Check the batteries for voltage
Sounds like it might be a fuel issue.

Many thanks to JLMunsil because after following his advice to get the manuals from aquahot.com, I was able to download an owners manual and a service manual for my particular model. The documents have answered all my previous silly questions.
Knowledge is power... now I know enough to be dangerous.

[Dr4Film]

I will suggest two things for you to do with new found knowledge.

Join Roger Berke's Hydronic heating forum @

Forum Rv Hydronic Heater Repair - Welcome

He is a wealth of Aqua Hot knowledge and experience. He also sells parts and repairs in his rolling shop.

Next, I hope you realize that the home base for Aqua-Hot is just up the road from you in Frederick, Colorado.

Dr4Film ----- Richard

[Wil Rathke]

I set both the diesel and electric switches on. I also wait until the diesel burner has stopped running before I turn the inside switch off to prevent "confusing" it.

[Dr4Film]

There's nothing to get "confused" if the diesel and electric switches are left on all the time. Both of my switches have been on since completing the last maintenance service which was done back in October 2012.

Depending on demand, heat & hot water, and the temperature of the incoming fresh water, that will determine whether the diesel burner comes on or not.

My switches won't get turned off until the next service is performed.

I wish someone could explain to me why it is necessary to monkey around with the Aqua-Hot switches.

The ONLY time I will turn off the Electric Assist switch is during the very HOT summer months when the diesel burner has never come on. This will force the diesel burner to come on which should be done for a few days every month. If you don't use the diesel burner routinely at least for a few days once a month, when the colder months are upon you AND you really need the diesel burner to work, it may not. Then you are in for some expensive service to get the problem resolved.

If I don't want any heat, I turn my thermostat off in that particular zone. If I don't want any hot water, I turn it off on the Manobloc Water Distribution panel.

Dr4Film ----- Richard

[Clayobx]

Richard is correct. Leave both switches on and use the AH much like loading up the generator every month. Most likely your problem was the system was not up to operating temp. By turning off the diesel switch and allowing it to reset then come up to temp your system worked as should. These are not complicated systems if used regularly. Glad all is well.

[Renipladlo]

You lucked out dude, the reset switch hole is directly over the "motherboard" of the system, you could have fried the MB, and that would have set you back around 500 dollars not being a dealer. Download the manual for your unit, read it, then download the service manual and read that. Keep a little round wooden stick (not conductive for electricity)(find the 25 amp DC fuse which controls the unit, carry several spares) in the junk drawer or tape it to the front panel of the HH unit, so the next time you need to reset it, you have it handy. The outside panel is held on with some compression type clips, it just pulls off, then you can see the little black reset switch which you can then push in with your finger. If you don't know nothing about these systems, you can screw them up big time and have expensive repairs which can costs thousands of dollars. I just spent close to 500 having a bad motherboard (my fault) and the flame sensor go out, needing replacement. I did not insulate the MB against bad sparks and killed it, the flame sensor lasts about 5 years at best, and then will usually need replacement. With the ULSD now, you can go two years between service provided you don't have lots of black or white smoke coming out of the unit, a little of either at startup is most likely normal. Don't short cycle the unit, that means don't turn off the diesel switch when it's burning, bad things can happen over time doing this, plus builds up lots of carbon in the Combustion chamber-BAD. Check the overflow tank weekly if excessive use is being incurred due to weather conditions. Run the unit on diesel every month for two hours making sure that you turn on the heat for both zones as well, to keep the HH fluid thin, over time of unused it gets thick and plugs up the stir pumps. If equipped with the engine preheat feature, use it as well for two hours a month, it has a separate stir pump when the HH unit is running. Don't just poke around into things not knowing what the heck you are doing, that is how people are killed.

[Wil Rathke]

I've found that the spray tube on WD-40 and such works quite well. I keep mine tucked in the wiring harness by the HH motherboard.

[highsticker]

sorry so late with this but with hy dro hots or any diesel furnace you should run #1 or blened fuel and or use 100 watt bulb by fuel filter i leaned the hard way.