I will be adding updated photos soon but some people were asking about furnaces and such so decided to repost the pics with water heater. I will take pics of the radiant heater and post them by this weekend.


http://www.photoshow.net/LibbyCal/renovations

Cheryl thanks for the repost. It's a well laid out production and a good showong of what can be done to these FG's

Thanks, Cheryl.

That's one cleverly constructed radiator.

Nice job Cheryl! I have been thinking about exactly what you have built. Can you elaborate on how you plan to make it all work and will you mostly be on shore power or boondocking. Are you using your water heater for sink and heat or just dedicated to heat. How do you plan to prevent running your heating water dry? What type of power load does the whole system have on it? As you can see I have many questions that I haven't quite resolved in my head.

Since we mostly boondock everything needs to be battery powered and running a 4 amp pump isn't going to work very long.

Thank you for reviewing our project. Here is the low down from my husband. If you have any questions just drop us a line or come see the unit (hopefully) finished and installed at the Oregon Gathering.
The water flow in the Boler is as follows. Potable water from the water tank flows thru the system pump and is pressurized to 20psi. The cold and hot water lines are teed at the water heater and a parallel loop flows through the heater coils a 1gpm pump and back to the water heater. Electrically when the thermostat senses cold it closes a relay that starts the circulation pump. When the coils heat up to 110degrees the fans turn on. Each fan has its own thermostat to start airflow at that temperature. When the trailer warms up the thermostat removes power and shuts down the pump and fans both.
We expect a 20 - 50% duty cycle depending on what we do for insulation and outside temperature. The water heater should stay full because the water returns to the cold side. The pump is the weak link. Right now we have a pump that draws a measured 1 ½ amp with full open flow. The fans draw 1/3 amp each and the relay, thermostat and electric start for the water heater are negligible. Operating for 30 minutes per hour at 50% we will draw about 2 amp hour so a 20amp hour battery will last 10 hours. (overnight) Some of the nice things I wanted to do is have it warm before the air fans start to avoid a flood of cold air. Also by having two thermostat switches the fans start up one at a time and hopefully won’t wake us up every ½ hour. By replenishing the potable water every week or so we avoid Legionnaires Disease by storing warm water.

Cheryl, very cool (warm) idea Something I'll definitely have to consider so that I don't have to listen to the noisy furnace that came with the trailer.

Thanks for the details. The control sequence seems quite sensible; the idea of not starting the fans until the water in the radiator is warm is normal practice for home furnaces, but I think many people would not have thought of that detail.

When the main thermostat calls for no more heat, and the circulation pump stops, are the fans really stopped then? They could be left to run until the water temperature is back down to their thermostat's switch-off point.

Cheryl, when you say the pump is the "weak link", do you just mean that its power consumption (1.5A) is the limiting factor to endurance, or is there some other issue?

We are looking into impeller pumps to limit the noise since they are more efficient so will use much less power. The pump we have now is a diaphram pump and will use max flow of 4 amps. We will never use that much. We have a pressure pump and really only need a circulation pump. Any ideas? We are looking at a few but have only found some pricy ones that will take the water temp. max.

Will be adding a few photos soon of the new water intake and outflow. We are trying to move as much as possible off of the side of the trailer so we have a cleaner smooth surface. The new hook ups are on the inside of the wheel well on the same side. They have the quick release connections so are easy to attatch and release. No more city water fill on the side of the trailer
We are also looking into the thermoelectric refrigerators. So far the Igloo Kool Mate 40 Cooler/Warmer 12V DC is what we are looking into. It will fit the dimensions of our cabinet which the new refrigerators do not. They are all to deep. We dont need a freezer and so think this will work out better. Also no need to hook up to propane only 12v.

The only idea which immediately comes to me for a low-head hot water circulation pump with DC power would be an engine coolant pump. I know they are normally belt-driven, but there are some which are driven by a 12VDC motor, for use on some types of race cars (NHRA says this has been the common practice in drag racing for years). That would be a good match for supply power and temperature, but most are likely far too big (twenty times the flow you need) and too expensive ($200 and up). Maybe someone makes a small one for drag motorcycles?

I am generally not impressed with the quality of aquarium equipment, but they do have small separate circulating pumps for large tanks (especially marine, or salt water, environment); they are often used with warm water, but I don't know about their tolerance for hot water, and I assume they're all 120VAC.

Of course commercial hydronic heating systems for RVs use circulation pumps, but I assume the idea is to avoid the mega-dollar off-the-shelf solution.

I wonder if a small pump like this would work?

http://www.wholesalepumps.com/Product.cfm?DID=41&PID=811

Rob's SolarMaster find looks good. There are also the various pumps used for portable shower arrangements. I don't know if either would be quiet or durable enough, but both seem like about the right capacity.

That SolarMaster looks like an aquarium pump to me, with magnetic drive (very handy, no moving seals to leak) and very simple impeller.