Recirculation System

Okay, ACE, this one is aimed at you, but all ideas are welcomed.

I have decided to follow the path of Fire Trucks and set up a recirculating water system on my box truck to keep it from freezing up en route to the jobsite. It will not do anything for my tools and chems, but if I can keep the water moving in the system, I can carry a small selection of gear in the cab with me and be okay for winter.

The question is how do I do it?

My intentions are to install a 12v on-demand water heater connected to the system so that I can circulate the water in a loop with some temperature rise in the process. It would have to pass through the fresh water tank, circ pump, water box, and cat pump en route back to the fresh tank and 12v water heater.

Is this an achievable idea or is this really just a PITA with little gain kind of thing?

Ok, this is something I have been thinking about for a while. But haven't had a  opportunity too try out. For your freshwater tank I've been thinking if you used say 10 feet of 3/4" copper tubing coiled in away that you can get it in through the top of the tank then tie it into the the vehicle coolant system so the coolant is being circulated through the cold by the engine water pump. With a reduced outlet on the coil to 1/2". 
Now Rob this is for you. There is a kit for adding a rear heater to vans or older vehicles that never had a heater. It has a 12vdc fan motor on it that could be used to blow heated air towards the cat pump and unit. You would need to plumb it first then to the coil and back to the engine. Then with a cutoff valve in one line to stop water flow. Let me know what you think.

That was my first thought too, those Mohjave heaters. My concern would be that the hoses would have to pass through the exposed space between cab and box which could reduce the temps and possibly affect the engine cooling system.

I could route it through a pvc pipe or something, but I would be treading pretty deep into the jerry-rigging pond with that set-up.

With the propane bottles getting mounted outside the box and not connected, I might be able to use radiant heaters mounted on the ceiling. I do have a circuit pre-wired into the box for lighting, so I might be able to power something that way.....probably not able to feed too much power though.

Webasto heaters that tapped into the fuel tank sounded like a good idea as well, but the output isn't strong enough to make enough impact....remember, this thing has air gaps along each door so it is liking driving an open window.

I just ripped one of those heaters out of the express. coolant lines all the way to the very back then they run through a heat box

The key is that they were still inside the vehicle and not exposed outside. In my case, I would have a 6 feet space where it had to run outside. That and these diesels don't seem to generate as much heat in the first place.

They are forecasting a warmer than normal winter, so maybe it will not be too bad this year. I only wanted to use the box truck on the larger commercial accounts where I need to carry 400 feet of hoses. That is only about 4 times per month....hopefully, they will be in the low 20's on those nights.

I may just have to buy a few pallets of RV antifreeze and plan on spending a lot of time winterizing.

The only thing left that I know of left is. Buy a power inverter couple queen size electric blankets and some moving blankets. Wire the inverter to the truck battery with 10ga wire mounted inside the back. The electronic blankets don't pull a lot of amps. Wrap the unit with one put the moving blankets on top of that. Use the other one to wrap wands hand tools chemicals the same way. The movers blankets hold in the heat .If you can't heat the room heat the components. This also works for shops even the guy's in the mountains of NC and Tennessee do this and their equipment rarely freezes. Solution lines can be blown out with air wands also. You could use the 12vdc pump to keep the water in the water tank moving, you can wrap the tank with plastic then electric blanket.

I think you hit it on the head ACE:

"...can't heat the room heat the components"

I like that approach....time to get to work while the temps are still above freezing.