From propane to diesel, a heater installation

[Jsoboti]

Decided to swap out the propane heater for a cheap Chinese diesel heater. To see a list of parts I purchased, see my post at

https://www.wanderthewest.com/forum/topic/25331-heating-options-for-fwc-fleet-high-elevation-winter/

In addition to those items, I also purchased...

10L HDPE Jerrycan from US Plastic. This is the only 10L container I could find that would fit in the propane compartment with 1 propane tank still installed. Also purchased a standpipe and fuel line quick-disconnect kit. Still need a check valve to vent the tank. 10 Liter/2.64 Gallon Natural HDPE Jerrican with 51mm Tamper-Evident Cap | U.S. Plastic Corp.

Universal turret mount, used on almost every install on YouTube. https://www.amazon.com/gp/product/B0CB66C36W/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1

Exhaust Heat Wrap to minimize possibility of the exhaust melting the fuel line. They're very close to each other. Amazon.com

Stainless Cover. https://www.amazon.com/gp/product/B07T2ZY643/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1

 

[Jsoboti]

Step 1 was to remove the Attwood/Dometic heater. After removing the plastic cover inside the camper and the 2x brackets mounted to the front of the heater, remove the exterior cover. You'll have to remove the black plastic surround before the heater will come out. To do that, you must bend the silver metal tabs to face outward.




Next you'll disconnect the propane line. Your propane is OFF right?Then you'll have to carefully separate the black plastic surround from the camper siding. It's REALLY on there because of the Butyl tape.



Once you plastic surround is removed, you should be able to push the unit into the camper. Disconnect the 4 electrical connections. 1 Pos, 1 Neg, 1 Blue Thermostat, and 1 additional blue wire, no idea what it's used for.



For size comparison, here is the diesel heater sitting in the propane furnace compartment. The size difference is incredible. I can't believe they don't come like this from the factory.




Hopefully next post will have the unit installed!

 

[Vic Harder]

Thanks for doing this write up. I suspect I will be doing this for my next build!

 

[goinoregon]

i put a propex propane heater in my ATC, and it was similar in size to this diesel. the propex was very tidy, and easy for even me to install.

 

[tstumpfig]

Great stuff so far, can't wait for the next episode

 

[Jsoboti]

Made some progress today. The hardest part was figuring out how I wanted to mount the heater and where. Space for the combustion air intake and exhaust is tight as I only have 3 inches from the outermost wall of the camper to the bed rail of the truck.

I settled on a turret mount, which required drilling a 5 inch hole through the camper. Scary! And also surprisingly difficult in such a small space. I started by drilling a pilot hole, to test how far inward I could drill the hole, without hitting the outermost wall of the camper.

Pilot hole drilled

https://www.wanderthewest.com/forum/gallery/image/24558-drill/

View from underneath. This tells me I can cut about 3/4" inward from where this hole is drilled, without hitting the lower wall of the camper.

https://www.wanderthewest.com/forum/gallery/image/24557-drill-bit/

Once I figured out how far inward I could drill the hole, I grabbed the 5" hole saw. I was surprised to see the construction under this cabinet. A layer of plywood, an air gap, then another layer of plywood. There was an extra piece that did not extend all the way into the hole, which I carved out with a chisel.

https://www.wanderthewest.com/forum/gallery/image/24555-half-hole/


Once that small piece was out of the way I was able to finish the cut with the hole saw. I used a 2 part epoxy to seal the raw edges, seems to have worked well.

https://www.wanderthewest.com/forum/gallery/image/24551-hole-straight-down/

As you can see in the above image, the bed rail will be an issue for the combustion intake hose. The intake hose would have to make a 90 degree turn in 1.5 inches of drop. I think that tight of a bend may break the tube. Any thoughts on using copper or PVC that has a 90 degree on it instead of the traditional flexible ducting?

The turret mount dropped into the hole.

https://www.wanderthewest.com/forum/gallery/image/24553-turrett/

The heater sitting in the turret mount. May have enough room to turn this into a usable half cabinet!

https://www.wanderthewest.com/forum/gallery/image/24554-heater-in-place/

I think the rest will require the camper to be off the truck. Hopefully I can get it pulled off sometime this week.

 

[Jsoboti]

I decided to bench test the heater as once it's installed, it will be really difficult to get out.



I couldn't get the unit to fire up fully, kept getting E-10 fault code. Which the internet says is either a Temp. Sensor Failure, or simply "Failure to start". I'm leaning towards the latter. I think I need to come up with a better solution for fuel delivery in this setup. I ran 4 priming cycles, but with the relatively clear diesel, it was difficult if the fuel hose was completely full of diesel or not.

I'll rig up something better and give it another shot. I won't install the unit until I know she can work properly.

 

[kmcintyre]

Nice progress. I'm sure many people have had the conversation with FWC about furnance options (like me) and have received the same answer. If there was an approved / certified RV furnace they would have used it by now. You'd think some company would recognize this "gap" in RV furnaces and develop better options.

 

[Vic Harder]

Dunno about “improved” since one would have to know what all the design parameters are that RV builders are looking for. Seems some builders think Propex, Truma, etc are “better” but other builders do not. Hard to judge when we don’t know what their priorities are.

 

[goinoregon]

I agree with Vic.
I also wonder if the 5" hole is really necessary ? that seems a bit large. when i did the propex, i drilled an exhaust thru side, and then snaked the fresh air intake out back towards the rear tie down area. go

 

[pvstoy]

Then you are at the mercy of being California compliant.

 

[Vic Harder]

I agree with Vic.
I also wonder if the 5" hole is really necessary ? that seems a bit large. when i did the propex, i drilled an exhaust thru side, and then snaked the fresh air intake out back towards the rear tie down area. go

Likewise. Two 3/4" holes.

 

[Jsoboti]

Agree the 5 inch hole isn't 100% necessary. It does help with shielding heat thought with the unit raised up. If the unit was flush with the bottom of the cabinet, the air intake hose wouldn't clear the bed rail. Most of the YouTube mechanics seemed to be using these turret mounts so I figured I would as well. Hopefully it wasn't a mistake!

 

[Jsoboti]

Realized the heater was sitting too low in the cabinet, would have been tough to get clearance for intake ducting and combustion intake hose beneath.



Decided to make a spacer for the turret mount to sit on, raising the heater up about 1/2 an inch.



Heater sitting on the spacer, much mo betta for clearance to the bottom lip of the exterior opening.



Used a high temperature sealant around the turret mount to prevent any exhaust gasses or moisture from getting back inside the camper.



Turret mountain installed on the spacer



Ran the combustion intake hose forward, mounted as flush to the camper as I could. Worried about crushing it while putting the camper on the truck. I ran the 4mm fuel line through a slightly larger plastic hose for a little added protection.



Ran the exhaust aft. Wrapped most of it in exhaust wrap to help protect the fuel line and the camper from heat. The way I had to cut the exhaust hose, I can't get the muffler on. I need to expand the hose about 1-2mm. Not sure how I'm going to skin that cat yet.



View looking up underneath the turret mount. major PITA to get the hose clamps tight. Should have assembled it all on the bench and put the turret, heater, hoses into the camper at the same time. Seemed almost impossible to secure the turret mount with the heater already bolted to it. However, that is how most people on YouTube seem to do it so it must be possible.

I also used the same high temp. sealant around the bottom lip of the turret mount again to seal out exhaust gasses and moisture. Not the prettiest silicone job but hey, it's DIY.




So far I'm happy with how it's progressing. Fuel system and electrical tomorrow!

 

[goinoregon]

nice work. thx for pics. maybe you could add some 'pipe' sections to cover the pipe. might help from getting crushed when putting camper on.

 

[Jsoboti]

I ran the fuel line as close to the camper as possible to make sure there's enough clearance when the camper goes back on the truck. The end goal was to get the fuel line into the propane compartment. If I had gone straight back into the compartment, the fuel line would have come into the compartment too low and the propane bottle would be interfering with it and wouldn't sit right. So I had to run the line up into the camper and then back into the propane compartment.



I went back and sealed around the split loom with silicone after, don't have a picture of that thought



Fuel line coming into the the camper then back into the propane compartment. The 4mm rigid fuel line is protected by the clear vinyl tubing and the split loom. Seems good enough



Fuel line coming into the propane compartment. Its just high enough that it clears the propane tank.



I wanted an easy way to get the diesel tank out of the camper, so I added a quick disconnect to the fuel line



Tank in place with the fuel pump mounted. I wrapped it in foam to try and reduce the noise. It's really not bad in the camper but I'm going to continue to try to figure out ways to make it quieter. Right now the pump mount is just screwed into the plastic of the propane tank liner. I'm not 100% satisfied with it, I'll have to find a better way to mount it in the future.




I did a very rough job on the electrical to get the heater up and running. Easy install, just used butt terminals and crimped them. The heater comes with a fuse on the positive but I used power from the campers fuse box so I got rid on the one on the heaters harness. I still have to make it tidy and mount the LCD, but she runs.

The connector for the fuel pump is quite large, to get it into the propane compartment would have required drilling about a 1.5 inch hole. So I just cut the cable, drilled a 1/4" hole, fed the wire into the compartment, and then crimped the connector back on.

I still have to make a new cabinet face with the hot air output, and modify the stock heater's outer cover vent to accept the diesel heater fan intake. Not really sure how I'm going to do that yet. I'll be traveling for the next month so those projects will have to wait. I'll update when I'm back

 

[Jsoboti]

Returned from my work trip and "finished" the heater. It's usable but not 100% done. It fit on the camper perfectly, no risk of crushing the intake or the exhaust. Phew!

First step was to fill the hole in the external cover. I cut a piece of sheet aluminum, painted it, and epoxy-ed it to the cover.



I used a 3 inch hole saw to the cut the hole for the vent. I used 3 inch ducting to run from this vent into the intake of the diesel heater. I used black silicon to seal everything up.


I mounted the controller where the OEM thermostat was mounted. Easy to route the cable above the cabinets and into this spot.


I made a simple face to cover the compartment. It will eventually be painted by my much more creative and artistic girlfriend. for now it does the job.



I'm still in the trial and error phase of how/where to mount the fuel pump. Using a rigid mount resulted in being able to hear the pump too much IMHO. Mounting it on these zip ties and resting against this bit of foam REALLY cut down on the noise in the camper, so much so that you can just barely hear it if you listen for it specifically. I think I'll secure it with some elastic instead of zip ties for a final install.


The fuel system is OK but I would prefer a different tank. The standpipe in the fuel tank was difficult to mount and doesn't sit quite flat. If anyone knows of a fuel tank that would be better for this application, please let me know. There's one that seems perfect, but is only sold in Australia and they won't ship to the US. I still have to vent the fuel tank too, thinking about using a dirt bike fuel vent on the cap. Anyone with experience with these?



I used the heater for the first time last weekend. What a difference. Hanging out in the camper with outside temps around 30-ish it was easy to keep the camper at a steady 68 degrees. I modified the mixture for altitude, instructions easily available online.





Over night the temps were pretty warm outside, between 29-32 degrees, super warm for the Sierra! I ran the pump on 1.6 Hz. I woke up pretty warm and had to turn it down to 1.2Hz. Camper was about 62 degrees when I woke up and DRY!!!! Id say condensation was reduced by 95% compared to running the propane heater over night with similar ventilation.

 

[ski3pin]

Thank you for the posts on your install. Good job! As you gain experience using it, could you comment on amount of diesel used?

 

[Vic Harder]

Also, I am super puzzled about your comment regarding condensation. Both the Attwood and the CDH vent combustion gases (and water vapor) outside. The only difference is that the CDH as installed draws both combustion AND the air to be warmed from the outside. Is that enough of a difference? I can plumb my Propex to take in outside air for warming too. Just wondering if I want to do that.

I'd love to hear others chime in on the why of drier air when we pull the air from outside rather than recirculating it. If I were to try to explain it, I would start by:
- Assuming 50% (Relative Humidity) RH at -10*C outside
- Same 50% RH inside the camper, but at 15*C
- Want to heat the air in the camper to 20*C

Scenario #1 - recirculate the heated air
- As the heater runs, it warms up the inside air, increasing its capacity to absorb moisture and thus lowering the RH inside the camper
- This air then sucks up moisture from wet things inside the camper, our sweat and breathing etc
- Eventually the air in the camper get's moist, say 70% RH at 20*C
- We turn the heat off and go to bed
- As the temp drops, water starts to condense out of the air which can no longer hold that amount of moisture.... cold surfaces first
- Many of us complain on WtW about condensation....

Scenario #2
- same as above, but we are always pulling in outside air to heat up
- The heated air coming in is always going to be drier, and contributes to constantly lowering the RH in the camper
- "Extra" warm air exists the camper via leaks, fan, etc
- So we blow in yet more warm (and drier) air.... using more fuel
- The RH in the camper never rises above the 50% (or whatever) it started with
- As the temp drops, there is less moisture to condense out.

Plausible?

 

[craig333]

I've given up on trying to convince people a propane furnace doesn't add moisture. In the hardest rain I've ever been in moisture began seeping in past the stitching in the top. Only took a short amount of time running the furnace to completely dry everything out.