Ghetto Hydronic Heater

[ericpeltier]

So.....I was thinking about heat in my camper. Future camper, really. Much to do before this specific project.

So, the forced-air furnaces have never impressed me. They're loud, and, we've had trouble with them at altitude. When we have shore power, we use a silent oil-filled heater. When we dry camp, we have to use the dreaded propane furnace.

Has anyone ever run water a loop from their water heater to a small radiator? It would need a small pump on a thermostat, of course. I could just leave the water heater on all night (on propane, of course). It makes almost no noise at all when it fires up.

Are small circulation pumps just not rated for the high water temp?

Is my 5-gallon water heater simply not capable of the BTUs needed?

Or, is there another reason not to do this?
Thoughts?

[Piggy Bank]

You have hit upon the problem.

Small water pumps, such as used in the HVAC industry for condensate, are not rated for very hot water temps.

The only pump I am aware of rated for steam temps is made by Hartell, and is quite expensive.
https://www.armstronginternational.c...df/hartell.pdf

[barts]

The following pump is good for 175 psi and 250 F, which should easily handle your hot water heater output .

http://www.thesolarbiz.com/EL-SID-SI...mp_2#gsc.tab=0

We went another route with a Dickinson marine propane heater. It has a tiny fan, but you can turn it off.

[Piggy Bank]

Thanks for the info Barts

[Foiled Again]

There was a thread many years ago by a man who had made a radiator system using a second water tank. Apparently it worked well but he had a small trailer. He did use a computer fan behind the "radiator".

For those ancient enough to remember, most radiator systems use a gravity flow or pump the RETURNING cooler water into the heater. I'm sure the thread was from 2006 through 2008. It was also published in some kind of RVing magazine.

I doubt if there are links to it, and I'll leave the search to others; but I remember I was impressed - negatively - by how much fuel it took for the forced air furnace and how it literally blew hot and cold. I'm retiring - so I'll fix the problem with Arizona, Texas, New Mexico, etc.

Paula

[kscherzi]

I build my home with radiant heat 23 years ago. The supplier installed two Grundfos pumps to move the hot water through a heat exchanger and the house. They've worked perfectly for 23 years. They do, however, use 120 volts. Check out this article, it may give you some idea's.

http://solarhomestead.com/off-grid-circulating-pumps/

[lewster]

Precision Temp 'Twin Temp' and be done with it!! Tankless water heater as well and circulates propylene glycol to boot.

Uses small heat exchangers with silent fans to circulate the warm air.

•••••••••••••OR•••••••••••

Re-invent the wheel. 😄


Lew Farber
RVIA/RVDA Nationally Certified Master Tech
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Master Tech Energy Systems, Inc.
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Lifeline AGM Batteries**Magnum Inverters***Victron Energy Components
541-490-6357

[switz]

The German Truma "AquaGo comfort plus" instant on water heater has a built in hot water circulation pump that could possibly be used for heat. However, the propane consumption would probably be more per unit of time that the usual furnace. The Truma units are smaller than the usual 6 gallon storage water tank systems and use a little 12Vdcv for the control circuitry and only propane to heat the water.

We have the middle Truma "AquaGo comfort" model installed in both trailers as it has a small internal device to keep itself from freezing as long as the propane and battery power are on. Our storage unit provides 120Vac power, so the slight power draw is a non-issue.

[ericpeltier]

Thanks for all the replies!
Goodness, the Twin Temp units are expensive! But, as with many of these RV appliances, they production runs must be so small there's little economy of scale.

Too bad that pump linked above is $265. Makes my experiment quite costly.

Maybe, if I buy a new furnace, it will work better than the one I have in my modern trailer. That one has not proved reliable. But I'm still suspicious that the venting is too restrictive and the sail switch doesn't activate.

Eric