Small RV furnace for cab heat.........

[rswyan]

LOL. what you ideally want is the old VW beetle gas heater.
Eberstruder (sp?)

Originally called Eberspaecher IIRC ... the product name is now Espar, at least in the US.

Webasto is another company that makes a similar product.

They were very effective and provided about 20,000 BTU's of heat.

Yup ... I have the smaller unit in my van (D2 Airtronic) - it's a diesel unit, however they make use either gas and diesel.

About the size of a loaf of bread.

The design was similar to models that were certified for early aircraft installations.

Design was a double walled system that isolated the combustion chamber from the hot air chamber. Safety shut offs, over temp protection were also incorporated. All stainless fabrication, and glow plug ignition system. Military also used this design in various vehicles.

They aren't cheap (around $1K retail) but they are incredibly efficient ... I think mine uses around 1/10th of a gallon per hour at max setting.

Want heat ? ... just punch the "On" switch and the thing fires up and runs at max until it achieves the temperature you set and then it idles back to maintain the cab temp. Has three or four different speeds it will run at to maintain the temp set and will automagically cycle between them.

Unless it's extremely cold and windy out it will drive you out of the van at max setting.

 

[linrick1]

Be sure to post a picture of you blowing snow in your bathing suit. :laughing:

Absolutely not. Nobody...... at all......ever, for any reason, needs to be subjected to that sort of disturbing imagery.

Are you using 100% outside air rather than recirculating air from the cab? If so, does the heater give a "delta T" in the spec?

I am using 100% outside air, I believe it will help stabilize the furnace run time and aid in controlling condensation. The furnace is rated at 12000 input BTU's, 9100 output BTU's. Not certain if this the "delta T" per se, but is the only information I could find regarding performance.

I know of the Espar and Webasto units, they would be just the ticket for what I'm trying to do but would also require me to rob a bank to do it. Maybe if this setup doesn't work I'll reconsider....I do have a ski mask. Thanks for the input and interest, Rick

 

[chim]

The delta T is the difference between the entering and leaving air temperatures of the furnace. With recirculated air, the air entering the furnace to be heated is warmer to start with. The given rise in temperature provides much warmer air coming out of the furnace if the air entering the furnace is 50 degrees instead of 12 degrees.

I once connected a very large electric heater for a guy and it felt like the fan was running without the heat. It was blowing ice cold air. The clamp-on ammeter proved it was drawing the full load current and was producing the rated BTU's. Problem was the air in the uninsulated building very cold and the velocity of the air moving through the heater didn't allow it to dwell long enough to get warmed up.

 

[linrick1]

Getting closer to wrapping this project up. Painted the enclosure, mounted same with furnace and ductwork, ran the propane line, finished up the tank mount, mounted the thermostat to a magnet for adjustment purposes, wired in a switch panel for the wiper, lights, the furnace, and an extra for a fan. Test fired it for the first time today and I have to say that I think this is going to work out pretty **** good - good airflow and temp, thermostat works as it should, furnace fires easily and runs smooth. Will finalize the thermostat wiring once I find the right location for it, I think that will have a lot to do with how stable I can keep the temperature in the cab. Thanks for the input and interest, Rick

 

[quarencia]

Been following this for a while and I think it's awesome and you've done an amazing job. I've often thought about using an RV furnace to heat my porch. I hadn't thought about using it on the tractor until I saw this thread.

Saw the hydro flame tstat in your picture. Do you know if it has an anticipator circuit? Some of the older hydro flame stats don't and in a small space, you could get pretty wild temp swings. If it does, I'd adjust it to max anticipation as a starting point. If you get wild temp swings, you could replace it with a new solid state digital thermostat. You can get simple Honeywell units for about $20. I also think some protection around the propane tank is a good idea. At best, a punctured tank is a bad day for the environment. At worst it's an inefficient rocket motor or low yield IED. Either way, I wouldn't want the last two strapped 18" behind my but. Just my 2¢.

 

[pmsmechanic]

Interesting project.

 

[linrick1]

Thanks for the kind words and the suggestions. I have a tank guard/bumper fabricated from heavy wall tube stock and some plate almost finished at work, that will mount to the counterweight assembly and should prevent, or at least minimize the chance of unintended explosions. I will have to examine the thermostat more closely - I didn't notice any adjustments but will look again. Working out how to maintain a relatively constant temperature is going to be the next challenge. Thanks for the input and interest, Rick

 

[linrick1]

Two years later and this setup is the stones......Uses a minimal amount of propane, keeps me warm and toasty, defrosts the windshield, and makes snowblowing just plain fun, which is important 'cause I spend three to four hours taking care of not only my own driveway, but the road and the neighbors place too. Not a lot of ground speed, but a ton of volume - my next project is an impeller clearance setup and an electric chute angle control system .

 

[Travelover]

Two years later and this setup is the stones.............. .

Nice job and congratulations of the perseverance. :thumbsup:

 

[jenkinsph]

Good for you, glad it is working out and I remember this thread.:thumbsup:

 

[FredH]

It sounds like you pretty much have it figured out and Kudo's :thumbsup: to You for sharing .

This sentence though early in the thread almost made me fall out of My chair laughing :

" lack of any real effective place to mount them without one body part or another spontaneously combusting. " :laughing:

Being a trucker , I knew about the wabasto and espar heater's . Small , Effective , But not cheap by any means , thus I could see you going a differnet direction .

Good job . :thumbsup:

Fred H.

 

[dixstir]

I would never do the lp heater, we used to do that on some trucks, the instructions said not to be in it lp running, about 2 weeks later we went to gordys funeral.

 

[hddnis]

Nice setup. Clearing snow is fun unless you're freezing your nuts off and then you start to hate snow.

 

[handirifle]

LP or any gas driven heater can be safe or dangerous. This setup was done very intelligently from the getgo. The use of outside air and not recirculating air will almost negate the need for a CO alarm, but it isn't a bad idea. ANY furnace in your home can be deadly. Elec can start fires, and nat or LP furnaces can and will kill you with CO if there is a defective heat exchanger.

For the OP, the only concern I had when reading this (first read today) was it being oversized, but with you using outside air and not recirculating that reduces the Delt T mentioned earlier in the thread.

Nice work, and glad to see you stuck to your original idea. Using any type of engine heat exchanger setup would have required a lot longer warm up time before you got heat.

This project has me thinking of a cab for my riding mower, not for heat, but mainly for dust and pollen (shade wouldn't hurt either). My rider is big (Husqy GT52 with fabricated deck) it is not as big as your Steiner, so it would be a little trickier to design. Great work, look forward to your other ideas.