Still trying to figure out the AquaHot

[NLOVNIT]

Thank you but I'm not interested in replacing the AH. We just got home yesterday from our 2wk trip. I have yet to call AH, but will do soon.

Lori-

[pointrow]

There is really good AH tech in LHC Az. Roy Spencer 909 524 2489. He will work with you over the phone if your not close.
Seems AH just wants to sell parts when called for information.

[Victory Blue]

Originally Posted by Putter1

Hot water should not be so hard. Preheating, diesel, electric, timing when you want to get hot water? How about I want hot water when I want hot water? I have no stake in Truma, however we had a Truma AquaGo installed on our Vienna Renegade at the dealer prior to purchase because of all of the issues we heard about with different water heaters and never had a glitch. Turn the dial to ON and let the hot water flow. Picked up a 2019 Allegro Breeze last week and had the dealer remove the "stock" water heater and install a Truma prior to delivery. Worked perfectly on our short "test" camping run.

Tiffin has already gone to the Truma in the Wayfarer and starting with the 2020 models in the larger coaches. It is an easy install and certainly worth the investment. One thing that is hard to live without is hot water in a beautiful Class A DP. Now if you are tent camping.....you sort of expect a cold shower now and then.

Stan and Janice Michalski

You're comparing apples and oranges and drawing some unwarranted conclusions. An Aquahot system is considerably more than just a water heater.

This thread is about a problem that most of us with Aquahot systems don't have plus a minor misunderstanding about how the system works.

The 450D unit the OP has (and that I have) uses the engine loop to automatically heat water while traveling (no button to push) and conversely will use Aquahot boiler fluid (Engine Preheat) to warm the engine prior to starting; the engine block heater is seldom needed. The Aquahot also supplies heated boiler fluid for heated floors and for heat from blower registers near the floor.

The two heat sources are there to provide flexibility in how the boiler fluid is heated. In warm summer months the electric element is usually enough to supply continuous hot water. When the incoming water is colder or heat is required the diesel burner can be turned on. Any delay in hot water at the tap is due solely to the length of the piping run and is there with any system.

[jkorn]

I lost the 110v electric side of mine a year ago. The connection where the Romax running from the circuit breaker box was loose where it connected to the Aqua Hot. Tightened and all good. Small panel is removed to see the connection at the AH.

Careful, the breaker labeled Aqua Hot did not turn off power to the wire. Test it first before touching.

[Putter1]

Sorry about that Victory Blue! I was only referring to the hot water at the tap, not all of the other additional features the AH provides. My fault for jumping the gun!

[alank]

Originally Posted by Victory Blue

The 450D unit the OP has (and that I have) uses the engine loop to automatically heat water while traveling (no button to push) and conversely will use Aquahot boiler fluid (Engine Preheat) to warm the engine prior to starting; the engine block heater is seldom needed. The Aquahot also supplies heated boiler fluid for heated floors and for heat from blower registers near the floor.

Here's a part of the 450D unit I don't understand.
You say there's an engine loop to heat domestic water while traveling. I've had this feature before in regular RV water heaters and it was from the engine water pump running engine antifreeze through the 10 gal. water heater and back. What water is this engine loop heating? I thought there is no tank in the Aquahot.

Does the 450D get it's engine heat from the engine antifreeze?

Is the engine antifreeze and the Aquahot boiler fluid all the same fluid and in the same circuit?

Are there more than two pumps in the Aquahot for boiler fluid? I know I have two, one controlled from the front thermostat, the other controlled from the rear thermostat, and both are for heating the coach.

I also have two heaters in the lower bay's, each with a thermostat. What pump do they turn on?

If I do engine preheat, what pump gets turned on to pump liquid to the engine, or is there a third pump?

Is it pumping boiler fluid or engine antifreeze to the engine?

If one of the two Aquahot pumps gets turned on to heat the engine, wouldn't it always be heating the engine while the interior thermostat is asking for coach heat?

These questions come from looking at the pictures provided in the Aquahot manual and I can't identify enough components to do all the things claiming to be done by the Aquahot.
Any help appreciated.

[Victory Blue]

Originally Posted by alank

Here's a part of the 450D unit I don't understand.
You say there's an engine loop to heat domestic water while traveling. I've had this feature before in regular RV water heaters and it was from the engine water pump running engine antifreeze through the 10 gal. water heater and back. What water is this engine loop heating? I thought there is no tank in the Aquahot. There isn't a tank. There's a long copper loop filled with water that is wrapped around the Aquahot boiler; the boiler is filled with hot boiler fluid. As hot water is used incoming water is heated continuously in the copper loop.

Does the 450D get it's engine heat from the engine antifreeze? Sort of. The engine water pump circulates engine coolant past the Aquahot which heats the Aquahot boiler fluid; the boiler fluid heats the water.

Is the engine antifreeze and the Aquahot boiler fluid all the same fluid and in the same circuit? Different coolants, different circuits.

Are there more than two pumps in the Aquahot for boiler fluid? I know I have two, one controlled from the front thermostat, the other controlled from the rear thermostat, and both are for heating the coach. This may depend on your installation. Click on the pdf the diagram below that shows the setup on my coach.

I also have two heaters in the lower bay's, each with a thermostat. What pump do they turn on? I can't answer that, but on mine it's pump 2; see diagram.

If I do engine preheat, what pump gets turned on to pump liquid to the engine, or is there a third pump? There's a separate pump; see diagram.

Is it pumping boiler fluid or engine antifreeze to the engine? The Aquahot only pumps boiler fluid; it's propylene glycol, generally recognized as safe (GRAS). Typically the engine coolant is ethylene glycol; not GRAS.

If one of the two Aquahot pumps gets turned on to heat the engine, wouldn't it always be heating the engine while the interior thermostat is asking for coach heat? No; there's a separate pump for engine preheat which is why it needs to be turned on to preheat the engine prior to starting and off while driving.

These questions come from looking at the pictures provided in the Aquahot manual and I can't identify enough components to do all the things claiming to be done by the Aquahot.
Any help appreciated.

Please see above.

AQUA HOT PANEL.pdf

[alank]

Thanks Victory Blue for your insight on the AquaHot operation. I also found a good manual on the 450DE and will add a few comments to the above post.

The engine antifreeze and boiler fluid are in separate circuts and never mixed.

When the engine is running, the engine water pump moves engine antifreeze to heat the AquaHot boiler fluid which in turn heats the domestic hot water.

The manual says there is a tank for the boiler fluid where the electric element or diesel burner heats the boiler fluid. There is no tank for domestic hot water. Domestic water is heated as it passes through a copper coil getting it's heat from the boiler fluid.

The manual said there is a mixer pump that will mix the hotter boiler fluid on the bottom of the tank with the cooler fluid on the top of the tank to keep it more even during the time other pumps are not running to mix the fluid.

If your coach has two heat zones, the AquaHot will have two pumps, if it has three heat zones, the Aqua hot will have three pumps, etc.

If you have engine preheat, it turns on a separate electric pump to circulate the engine antifreeze and only will operate if the diesel is also turned on. Will not operate with electric boiler heat.

The basement heaters will turn on one of the coach boiler fluid pumps to heat the basement area. This will also pump boiler fluid to the coach area, but without the fans coming on, will only put minimal heat in the coach. Most likely if the basement needs heat, the coach will also need heat so probably not an issue.

Hope this helps with understanding the AquaHot operation.

[RTC1]

I talked to Ken Beal from Tiffin at the Tiffin rally in WV about the aqua hot and he told me that when travelling to get heat to the furnace thru the aqua hot to leave it on diesel. If the engine heat does not provide enough heat for your setting then the diesel burner will kick on. We always have hot water after traveling for awhile but the heat to the vents has been sketchy. I had my aqua hot serviced at rally and am now getting a fault code on diesel when leaving it on overnight. So I will now check my connections to see if maybe the service tech didn't plug something in right. Lori your not the only one confused about this system...

[NLOVNIT]

Thanks RTC1. I did learn to put the switch on diesel to get furnace heat to the coach while traveling. That was something I didn't know prior to PM'ing with member jlturner.

An update with my situation. I got in contact with Spyder first, to see if the FAULT might be an issue with signal to the panel. Christian says : I believe this is a issue with the Aqua-Hot module."

So I contacted AquaHot. First Danielle says I should be able to have both electric & diesel on with no problems. Second, she also said: "The electric side is meant to give you enough hot water to do a load of dishes in the dishwasher and that is it."

So that confirms hot water on electric is limited. I knew it was, but didn't know it was that limited.

Since we've only had the coach 6 months & we don't know if the PO did the annual service to the AH (since they had it less than a year), the first thing Danielle told me to do was get the annual maintenance done. Because we didn't have a long enough trip (until the 2wk trip we took just last month) for me to do a long-term test of the system with the different options & options combinations & because now the coach is winterized & put to bed for the Winter, that service is first on the to-do list come next Spring.

Thanks to all who offered advice. I'll report back next year after I get the annual maintenance done & after I've had time to re-test operating with the different heat source options.

Lori-

[alank]

Originally Posted by NLOVNIT

So that confirms hot water on electric is limited. I knew it was, but didn't know it was that limited.

Lori-

Look at it this way, the electric side is a 1600 watt heater, basically the same size as all the 1500 watt heaters you buy in the department stores. A 1500 watt heater produces about 5000 btu's of heat and the aquahot on electric will do the same, no more.
The diesel side of the aquahot produces in the area of 56,000 btu's of heat.
The amount of heat the two sides produce aren't "in the same ballpark" so to speak. Learn what 1600 watts is, and what it will produce, don't expect too much.

[NLOVNIT]

Thanks for that info, alank. I saw the label on the unit (as well as in the owner's manual) read 1650 in the Watts (AC) box, but had no clue what that meant or how to translate it into minutes worth of hot water, depending on flow rate. I also read (I think), something about the outside temp can't be too cold or the electric isn't effective at heating. When we had night temps in the 40's, I knew to use the diesel mode, since that's the primary heater for water.

Having come from a gas coach with an electric mode for a 10 gal water tank, I was expecting to have at least as much hot water out of the AH unit as I got out of the electric element heating the tank on my prior coach. I know there's no tank with a AH but I guess I misunderstood what not having a tank translated to as far as the amount of hot water I'd get during use.

So much to learn about this bugger!

Lori-

[alank]

Your previous gas water heater was a tank of about 10 gal. and was round with two ends, just like most people think of when you say "tank".

The aquahot has a tank, but it is for the boiler fluid, encompasses the diesel burner and is not a conventional shape. The domestic water part has no tank, but absorbs its heat from the boiler tank fluid. When the boiler tank runs out of heat to transfer to the domestic water coils, you run out of hot water.

I haven't seen any specs, on the size of the boiler tank, on how much fluid it will hold, but what I suspect from the pictures I've seen is that the fluid capacity would be in the gallon or two area, so it just doesn't have the volume that you have been accustomed to. Electric 5000 btu's will give you a little hot water, diesel 56,000 btu's will give you all you want.

Your coach at 40* outside temp will loose more than 5000 btu's of heat/hour, so you'll need the diesel setting to keep up with the heat you need.

[NLOVNIT]

Well, it's been a while (first winterized & put to bed for Winter, then the pandemic hit & haven't been able to get out). Now I've got an update for #3 in my 1st post of this thread.

We picked up our coach last week from having the maintenance done on our AquaHot. I did test the diesel+electric being on & no FAULT, but I guess I didn't test it long enough. First trip out this past weekend, guess what???? Yep, having both the electric & diesel systems selected produced a flashing FAULT on the diesel symbol on the Spyder panel within ~10 minutes of having both on at the same time. I did check the panel on the unit in the outside bay & NO lights were on.

I was SO hoping doing the maintenance on the unit would've solved that.

Then, a new-ish issue appeared. I had turned off both the electric & diesel for overnight. In the morning, I turned on the diesel to get a nice, long hot shower. About 20 minutes later (after coffee & checking emails), I went to get my shower & this time, the diesel icon on the Spyder was flashing FAULT! Geez! I turned the diesel off for about a minute, then back on again. No problem the rest of that day.

I've got videos of the Spyder panel with the flashing icons for both instances.

Today's a holiday, so I'll have to wait until tomorrow to contact AH to find out what my next move is to diagnose this FAULT issue.

Lori-