Hydronic Heat

[Murphie]

I am doing some research on installing a hydronic heating system in our trailer. I was wondering if anyone here has ever had one or know if it warrants the time and money spent installing one. I know they are very expensive to buy and are usually used on class A's with diesel motors. I read on the Internet about a guy who reversed his water flow on his hwt to stop cavitation and installed a heater core from an auto parts store to heat his trailer.

The floor gets very cold in the spring. I thought if I could run a line under the floor to warm it up in the area we walk it would help. I could send cold water thru in the summer to help keep it cool. If needed the holding tanks would be kept from freezing if a thermostat was used to control its use. I would still use the Atwood heater but possibly not as much. Anyone here looked into this before?

[RoyBraddy]

I don't know if that was my article you was reading or not... every post that is submitted on these forums end up on the internet. Just search google for your forum name and some unique key word and there they all will be... This is my plan for coming up with a hydronic heater system using the OEM water heater as source for hot water. This is for taking out the furnace and replace that opened up area with a AQUA-HOT heat register. This is for use in my OFF-ROAD POPUP where the oem furnace is just way too much heat, very loud blower fan, and consume 12VDC like crazy as well as propane. One of the guys on the RV has done something like this and made his trip up in the Alaska area and it worked just fine for him is his POPUP setup.

This is the basic concept



I will do up a proto-type this spring when i can lay under my POPUP and see what all I need to retrofit everything working with my OEM water heater... Using the one-way valve and hot water pump as shown here will not interfere with normal hot water use.


I am planning to use this AQUA-HOT 100 heat exchanger and this will be eventually installed in the spot where the OEM furnace was installed. Size wise this fit the hole perfect. I should also be able to re-use my furnace wall mounted thermostat as well. The thermostat will control both the fans in the heat exchanger and the hot water pump to control the heat level. The AQUA-HOT 100 will produce 4000BTUs of heat. If more BTUs is needed you can go with the AQUA-HOT 200 model which will produce 6000BTUs of heat.



Keep in mind this is going to be used in my OFF-ROAD POPUP and I think it will work just fine for us. Using this same approach in the larger trailer with built in heater ducts may need a larger BTU system. I have no idea of how you would replace your flooring with heater floor panel without removing every thing inside the trailer first which would be a major undertaking I would imagine. But just adapting the heat exchanger to supply heated air for the OEM heater ducts would be a very easy thing to do as in my case i am installing the AQUA-HOT unit in the same location as where the oem furnace was installed so I would have easy access to the already installed heater duct work. The problem may be you would need a larger blower motor system. You could also run more hot water hoses to the back part of the trailer and install a second AQUA-HOT heat exchanger with its own blowers and maybe between the two units you would have enough heat...???

Certainly is a neat project to play with... I'm thinking my total outgo of money for my project will be in the neighborhood of $300-$400...

Also another note for me is i can run my OEM HOT WATER heater from both propane or electric.

I think it will be WIN WIN for me with my OFF-ROAD POPUP.

Roy Ken

[Jagiven]

In a MH, it could make sense. In a TT I would think it would add a lot of weight, and it would be difficult to install and ensure the heat went where you want it. If you have an enclosed underbelly, it would have to be fully opened up so it could be installed. Then you still probably could not install the loops between the floor and the tanks. You would then need to insulate the floor to get the heat to go up into the floor. To power the system, I doubt your water heater would be strong enough, so a new electric micro boiler would be required.

At one point in time we had seriously looked at another brand TT. That brand would custom build them. We considered asking them if they would install an electric in floor heating system between the floor deck and the linoleum. The system I am talking about is commonly installed in bathrooms between the subfloor and the tile floor. My thought to install it would be to absolutely level the TT, install the wires then top the wires with a self leveling compound then install new linoleum. I am not sure if it would be a good installation method as I have not fully researched electric heat strips. I am sure this would be a lot easier than a hydronic system.

[Jagiven]

Here is a product that looks a whole lot easier. Portable Electric Radiant Heating for Under Area Rugs. For a TT it looks as if it would work.

[tinlizzie23]

Jason - that Rug Heat you mentioned would be a great idea even for the house to save on oil. And it might be just the thing for those early spring and late fall camping trips to keep the 5er furnace from using up the propane so fast. Thanks for the tip ! :applause:

[RoyBraddy]

This type of coils inside a rug might be ok if you are at an electric site but you probably will need a very big battery to keep something like this going when camping off the power grid..

Most of my trips are camping off the power grid so my efforts always have that in mind to be able to survive off the battery system and then be able to re-charge my batteries when allowed to run my generator the next morning.

NOTE: Just read the specs from the link above and they are alot lower BTU units that I was expecting to see. Let me back down on my comments on this being a really high energy consumption item. Of course running a 1500WATT electric heater is a somewhat large power drain from a battery system it is not impossible to overcome. It still will take a pretty big battery system to support the rug heater all night long. If you plan on doing some camping off the power grid using this heating concept all of this will have to be figured into your DC power budget.

Roy Ken

[Chakara]

There is a huge difference in off road/boondocking heat and full hookup campground heat.

When I had my Casita trailer I looked hard at something like what RoyBraddy is talking about. That was a few years ago and at that time I didn't find anything like what he came up with, namely the AQUA-HOT unit to simplify things. I was looking at car heater cores and mounting options. Never did move on that project for a few reasons, namely I was chicken in that there were few if any installs like it and well, I like tried and true.

Now, with the larger trailer that has its tanks underneath with some exposed pipes, well, I just can't see it working for me in cold weather. (I consider cold below freezing each night).

When hooked up, I love using an electric heater to warm the trailer. By far the easiest and most cost effective.

When boondocking today in cold we don't use the water systems. Instead keep a jug of pink stuff by the toilet for flushing and use water bottles for everything else. When I say cold I'd say expected temps below 20F. Here in NM, a 20F at night will equal a 40 or 50 in the day so not as big a deal. Those of you in cold climates have a whole 'nother set of issues

To the OP's post - I'm sure it has been done, but I question the value of a retrofit. I say that not knowing what you have for a camper - mine has essentially no insulation below the floor. Doing ti might be a chance to fix that

-Chak

[tnchuck100]

IMO this would only be a cost effective solution in a motorhome where you can use the engine heated hot water while traveling. In a travel trailer the use of multiple heat conversions would be inefficient. Propane > Hot water > room heat. Why not just use the Propane furnace and cut out the middle man. I cannot see any payback potential in this.

[Chakara]

I wonder tnchuck100 - the amount of heat lost in the furnace through the outside vent is considerable. It may be less loss.....

-Chak

[RoyBraddy]

I agree the system I was showing may not be the best fit for a larger trailer but for the 12-foot box I have with just one heat register I am going to get an hugh energy savings from my battery bank (almost half) and still be very comfortable inside the trailer. We can do just fine with the 4000-6000 BTUs of clean heat in our small floorspace.

I will firm all of this up once I am able to procure enough items to do some prototype testing to satisfy myself. The DC load will be very much reduced from not having to use the high current OEM fan (6-8AMPS) in the propane heater. It appears the DC load the heat register DC fan and the DC water pump in the above system is going to be at least half the load the propane heater DC fan draws. My system shown does not interfere with normal hot water use as well for the kitchen sink or one of those small built-in cassette pottie/shower setups...

A couple of guys that has already been doing this tell me the propane fired water heater only kicks in for a short time about every 10-15 minutes for a short period of time keeping the hot water up to temperature. One suggestion was to purchase a small 600WATT DC element for the water heater to run directly from the battery if it is only going be on for very short period every 15-minutes or so and get away from using any propane at all...

Keep in mind I am only looking for clean noise free heat when camping off the power grid in my 12-foot box off-road POPUP camper. If you get into the larger trailers maybe bigger than the 22-24 foot range then more heat registers will be required for this size hydronic heat system. I think the 6-gallon water heater will handle two heat registers ok but more than that will require a large water heater...

There is of course bigger hydronic heaters that would handle this but the size of the heater/water box will be the killer. They look expensive also. My retrofit is going to be in the $300-$400 dollars range it appears. I could reduce that by about $100 if I built my own heat register using automotive type heat exchangers (oil or water from auto parts stores) and build my own enclosed box using DC axial (muffin) fans... If you had access to a surplus electronics equipment rack fan enclosures that would make a nice 5-inch tall by 19-inch wide heat register.

Me just saying.... Have done alittle thinking about it...
Roy Ken