Adding Electric Water Heater

[VegasDogMan]

My coach has HydroHot - on demand hot water system and I'm not really thrilled with paying for diesel to heat water when I'm plugged into 50A .
Yes, it does have an electric heat element but it doesn't store enough hot water to wash your hands.

My thinking is that I can buy a 7 Gal electric unit and run the output of the HydroHot into the Electric Heater and when plugged into shore power (not inverter) OR when HydroHot main switch is OFF the system would automatically switch over run water theough the electric heater.

Need some sort of bypass valves system to allow use of either HydroHot or Water Heater to prevent HOT water produced by HydroHot from flowing through electric heater and Vice Versa.

Any plumbers or fluid technicians out there that can help me out with ideas?

[truk4u]

Lee,

I had an 04 CC Plastic with Hydro-Hot. I would take it any day over the Webasco because of the electric function. I found that if I left both switches on, diesel and electric, the burner really only came on during high demand such as showers. Most of the time the electric was able to keep up with our hot water needs. I also showered with just the electric, but it wasn't scorching hot, but still hot enough for 1 quick shower.

Don't remember if there is a temperature adjustment for the electric, but maybe your not getting to a high enough temp when on electric only.

The cold weather protection was fantastic using electric. I could heat the bays and keep the coach well above freezing with just the electric on while in garage.

[Jon Wehrenberg]

Lee,

Conceptually what you want to do is simple. "T" off the in and out lines from the Hydro Hot bringing them to an electric heater. When you are connected to shore power for long periods close the valves to the Hydro hot and open them to the electric heater. Assuming the electric service to the Hydro Hot is of sufficient size you can do the same thing to the electric power supply, switching it to go to the electric heater or the Hydro Hot at the same time you open or close the valves.

All of this presumes you have room to mount a second HW tank and that the Hydro Hot does not work on electric. My guess is it works well on electric, but as Tom suggests it may just be a thermostat adjustment.

[dalej]

One thought this,

I thought aqua or hyrdo hots were tankless. If this is the case just put the aux. hot water heater in front of the heater that you have. If you leave the aqua hot off completely the hot water will just run thru the heater but will allready be hot.

I'm just not sure the amount of line in the aqua hot that it would have to run thru to get to the fixtures. I guess if your plugged in you could leave the AC side of the hydro hot on.

Jon's post is about the only other way, just don't like to keep adding valves.

Is Hydro Hot and Aqua Hot the same thing or company?

[Petervs]

First off do a little math to decide if all this is really worth it.

A gallon of diesel contains 143,000 btus of energy. It can heat 143,000 pounds of water one degree F.

You are trying to heat water from say 50 degrees to 110 degrees. It will take 60 degrees x 8 pounds per gallon or 480 btu's to do one gallon. Assume the diesel heater is not perfectly efficient, so it will take 600 btu's.

So one gallon of diesel will heat 238 gallons of water. For about $4.00. 1.6 cents a gallon.

So now you are planning to spend a few hundred dollars modifying your coach. Pick a number, but to buy a tank, fittings, a few extra items, whatever, lets say $500 to finish the job. That works out to being able to heat 32,250 gallons of water before you have saved a penny.

Our coach holds about 200 gallons of fresh water, I suppose we heat 25% of it, the rest we use cold. The tank lasts us say 3 days so we are using about 20 gallons of hot water a day.

This works out to 1615 days of using the coach before you break even on the expense of modifying your system. We are assuming the electricity is free for this analysis too. If you are full time that is 4 1/2 years. If you are in the coach 50 days a year, which I suspect is high for most of us, it would take 32 years to break even.

I think your time is better spent flying or golfing or walking on the beach with your significant other.

[JIM KELLER]

First off do a little math to decide if all this is really worth it.

A gallon of diesel contains 143,000 btus of energy. It can heat 143,000 pounds of water one degree F.

You are trying to heat water from say 50 degrees to 110 degrees. It will take 60 degrees x 8 pounds per gallon or 480 btu's to do one gallon. Assume the diesel heater is not perfectly efficient, so it will take 600 btu's.

So one gallon of diesel will heat 238 gallons of water. For about $4.00. 1.6 cents a gallon.

So now you are planning to spend a few hundred dollars modifying your coach. Pick a number, but to buy a tank, fittings, a few extra items, whatever, lets say $500 to finish the job. That works out to being able to heat 32,250 gallons of water before you have saved a penny.

Our coach holds about 200 gallons of fresh water, I suppose we heat 25% of it, the rest we use cold. The tank lasts us say 3 days so we are using about 20 gallons of hot water a day.

This works out to 1615 days of using the coach before you break even on the expense of modifying your system. We are assuming the electricity is free for this analysis too. If you are full time that is 4 1/2 years. If you are in the coach 50 days a year, which I suspect is high for most of us, it would take 32 years to break even.

I think your time is better spent flying or golfing or walking on the beach with your significant other.

I ALWAYS enjoy reading Peters Posts !

[Jon Wehrenberg]

Peter, As usual your logic is perfect. Now back to reality however. None of us applies logic, even in modest amounts to buying a coach. Therefore, why would logic be applied to anything we do to our coaches?

[dalej]

Jon, I think Peters reply was based on Physics not logic. If I did things like Peter, I wouldn't do anything, because anything I do, can't be proven by physics.

I'm going with Lee on this one, just doesn't make sense to run a diesel fired furnace while parked in a campground. Logic tells me to use the electricity that I paid for.

[phorner]

For what it's worth, our '03 Beaver had Hydro Hot heating and we rarely used the diesel function for hot water, and we lived in it full time. I turned the diesel switch on most of the time just to exercise the burner and make sure it still worked..

We were very happy with the performance of this heating system, which was probably the best part of the coach.

I would make sure that yours is working properly before re-engineering the entire hot water system.

In any event, good luck with your project.....

[Petervs]

Jim Keller, I like you too!

Jon, I am not saying we need to only apply logic when doing things to our coach. I am saying, apply selective logic. Spend the time and trouble where it makes the most sense, like adding bling, polishing slack adjusters, or hey, what about this, driving more?

And Dale, were you Houdini in a previous life, physics does not apply to you? Come on, if you want to use more electricity, just boil water on your electric cooktop for washing your hands. Or, if you are not getting your fair share of free electricity use out of the campground, why not take up a nice hobby like arc welding scupltures to decorate your site, putting on even more lights to add bling, baking lots of cakes and cookies in your electric oven at POG gatherings. All these make more sense than adding an electric water heater. Come on agree, you know I am right.

[Jon Wehrenberg]

When you are right, you are right. Back to my slack adjusters....

[Ray Davis]

Do the Webasto uniits work significantly different than the Aqua Hot?

I've run my Webasto, turning on the diesel water heater switch (labled "12v water heater"), and if my electric water heater is on, it will run for only about 5 minutes, and that's it.

The diesel currently gets the water a bit hotter than my electric (not sure if that's just an adjustment), but I find that in general:

1. first day after driving, water is plenty hot from the engine
2. 2nd-4th day is fine on electric
3. then I usually kick it up a notch with the diesel, which burns for only 5 minutes or so.


Ray

[VegasDogMan]

After retinking the project DaleJ is right - put Electric heater Before the HydroHot not after.

I'm new to HydroHot and on electric Only it's performance is p... poor. Better call vehicle systems for opinin first... maybee heating element is shot.

Thats my to-do list for tomorrow...

Drove the Essex today for 1st time .. loaded with my stuff... Very windy Day and it doesn't hold road as well as my 40' liberty did. It's a bit higher, longer and maybee lighter... haven't weighed it as yet. Ride is a little bumpier as well.

Thanks for all the input on the water heater project. I've found a small 7 gallon water heater (Ariston GL6+) that will fit. Now to find someone here in Charleston, NC that has one in stock.

If, after my conversation with Vehicle Systems, I decide to go ahead with installation - It will be done before Sevierville.

[truk4u]

Dale,

Hydro-Hot and Aqua-Hot have their own coolant tanks. One is the big brother, I don't remember which.

[lewpopp]

Hey Dogman,

You can solve the hot water problem for you if you take your shower first and when the wife complains just say "you're the one who wanted the 4 slides, you said nothing about hot water also"

[Larry W]

I asked the difference between aqua hot and hydo hot whan at Vechile Systems. I was told the aqua hot has 15 gallons in the boiler section and the hydo is much smaller. On the plastic coach with aqua hot we had did not seem to have very hot water. I found a the fix as it seems they are concerned with the domestic water being too hot. On the aqua hot (not sure about hydo hot) the hot water coming out is mixed with a small amount of cold water so people like me won't it burned. In the aqua hot unit there is an adjustable valve in the cold water mixer line. You can adjust the temp of the water by adjusting the valve. Closing the valve some will limit the amount of cold entering the hot water, thus hotter water in the coach.
Your problem may be the water is not hot enough to take a longer shower.

[Gary & Peggy Stevens]

Larry W., thanks for the insite into the Hot / Cold water system in the Aqua Hot systems. I had to send your information on to a friend of mine that is complaining about his 04 CC Magna, and their cold showers.

I am sure he will appreciate your insite to this problem.

Thanks from both of us.

Gary S.

[dalej]

This was taken from their website, don't see where it would have a tank with hot water.

The Aqua-Hot 600-D model was our first RV Hydronic heating system introduced to the Bus Conversion market in 1989. This is our most powerful system and is primarily used in motorhomes 40' or more in length where storage bay space is more generous; and maximum hot water performance is a must.

Aqua-Hot 600-D Combines 3 Great Features in one Unit!

Continuous Hot Water
Separate Interior Heating Zones
Engine preheat/motoraide
Aqua-Hot 600-D Features:

Continuous supply of hot water - no storage tank needed, therefore you never run out.
Quiet operation - no need to turn up the volume on your TV whenever the furnace comes on.
Independently controlled interior heating zones - you put the heat where you want it.
Two 120 volt-AC powered heating elements can provide heat and hot water during low demand periods.
Minimal annual maintenance - fuel nozzle and fuel filter.
Burns low volatility, on-board diesel fuel, no propane required.
Safety features that shut-down your heater in the event of a overheat or low-voltage situation.

[JIM CHALOUPKA]

Lee, play the demonstration video and then you decide if your wife is correct in demanding an additional hot water heater, or if all you need are a couple maintenance parts and adjustments.

http://www.aquahot.com/ServiceTrainingVideo/index.html

Curious to know do you have the 60,000, or 45,000 BTU model?

Anyway I think your mind is made up and it's a done deal, but there may be a lurker that wants to see the demonstration.

[truk4u]

Dale ole buddy, I had two of them!

Ya see the coolant tank fill #3?

I'm not dreaming....:D


2445

[dalej]

I'm just thinking that the coolant tank is for engine coolant isn't it? There is no reservoir to hold domestic hot water is there?

Isn't this just an Insta-hot? either electric or diesel for the purpose of heating domestic water.

It is also used to heat engine and interior heat exchanger coolant.

My wabasto heats only coolant to circulate in the engine, heat exchangers and hot water heaters.

I thought the only thing they added was a coil for domestic water to pass through in order to deliever hot water to shower and do dishes.

I was thinking Lee didn't have enough hot domestic water with just the electric elements on. I would also check to make sure the one or two electric elements are working good.

[VegasDogMan]

Project is on hold....

Did some checking today and found that the High Limit thermostat (in series with heating element) is OPEN. Called Vehicle Systems and they said I could press the reset button on the thermostat.

Opened the unit again, found the reset button and IT WAS MELTED. Evidently there was an overheat problem at sometime.

Have ordered new limit thermostat and will see what the results are before going further..

Also will investigae Hot/Cold mixture and see what the situation is there.

Hey, you guys are a wealth of info.

Thanks..

[JIM CHALOUPKA]

Don't buy any tools, your wife will use that against you!

[truk4u]

Complete closed system. All heat is done by transfer via exchangers, coils, etc. Prior to mid 2004, they used regular anti-freeze (green). Due to a concern of contamination to fresh water through the heat exchanger coils with anti-freeze, they changed to Boiler Anti-Freeze. Boiler Anti-Freeze is pink in color and not to be confused with the pink stuff you put in your water system to winterize. It's hard to find and I have a gallon in stock if anyone needs it.

There is no mixing of the engine anti-freeze and the Aqua-Hot internal anti-freeze.

[VegasDogMan]

Jim C;

Speaking of tools - I'm in proces of updating my tool box. Just got complete set of Metric Sockets and Metric Open-End/Box combination Wrenches.

Now I'm having trouble finding a Metric Crescent Wrench and Metric Hammer.

[VegasDogMan]

The Hydro Hot uses Propylene Glycol as a coolant/heat transfer media. Coolant circulates through the radiators and heat exchanger tank where water passes through copper coils and absorbs heat from the coolant.

Only hot water reservoir is in the coils in heat exchanger tank.

The Hot Water Output temperature is lower than the Coolant temperature. That is adjusted by a mixer valve on the hot water output by adding cold water.

New things to learn and adapt to...

[merle&louise]

Larry W., thanks for the insite into the Hot / Cold water system in the Aqua Hot systems. I had to send your information on to a friend of mine that is complaining about his 04 CC Magna, and their cold showers.

I am sure he will appreciate your insite to this problem.

Thanks from both of us.

Gary S.

Gary,

I learned a little trick from JDUB @ Santa Fe rally about the Aqua Hot. When the CG water is very cold try filling your fresh water tank about 24 hours BEFORE you shower. Turn the heating thermostat in your bay up to about 70degrees and let the CG water warm up to about 70 degrees; this will give you a longer hot shower. The Aqua Hot can warm up water about 45 degrees; so 45 degree water coming out of the ground can only be heated to about 90 degrees, which makes for a cool shower. I tried this method of advanced filling and it works great.:D

[JIM CHALOUPKA]

Jim C;

Speaking of tools - I'm in proces of updating my tool box. Just got complete set of Metric Sockets and Metric Open-End/Box combination Wrenches.

Now I'm having trouble finding a Metric Crescent Wrench and Metric Hammer.

Lee, there's a tool shop near by, and I can get your tools special made!. The only thing is there really expensive, and the guy wants to be paid up front. So if your interested just post your credit card no and I will order them for you. Oh, by the way he has a real neat metric level and hand saw,:cool: interested??