From propane to diesel, a heater installation

[CPT Davenport]

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.

I too am curious about the extreme condensation reduction.

Did you still need ventilate when running the diesel heater? If so was it the same amount of ventilation as when you ran the propane heater?

 

[Jsoboti]

I agree with all of the comments above. It doesn't really make sense to me either. I'm not an engineer, just a dumb pilot and all I know is that I woke up to a basically dry camper and I was really really happy. My hopes were not high, as it was relatively warm and humid conditions, especially for the Sierra.

I think the biggest difference is using outside air for the heat exchange. This theoretically "should" create a slight over-pressure in the camper, resulting in a constant flow of warmed/moist air out of whatever vents are opened. Does it actually do this? No idea!

I agree that the the OEM propane heater doesn't add moisture, due to the heat exchanger, but I think re-heating the cabin air was the culprit.

Another added benefit of the CHD is that you can meter the heat and fan. The OEM furnace was all or nothing, and would cycle constantly. It was loud and used too much propane/electricity for my liking. The CDH can be set to a very low setting, basically silent, and will draw about 1 AMP while at this low setting. I ran the heater for about 15-17 hours straight, with 8 hours of it on a very low setting and I used approximately 1/4 of a 10L tank. Not bad for efficiency!

I know that heating outside air is technically less efficient that heating pre-heated cabin air, but the air coming out of the vent was so damn hot that touching the plastic vent to change the direction of airflow damn near burned my fingers. Honestly not too sure if I would even want it to be hotter. These things crank out some serious heat.

I still think ventilation is required with the CHD. I vented the camper the same way that I did with the propane heater. Both roof vents cracked, window by my head cracked. The storm was gusting 50+ mph winds or I would have vented a little more.

 

[CPT Davenport]

Thanks for the update and nice work on the instal! Please keep us posted on the continued performance of the unit. Isn’t winter camping the best?!!!!!!

 

[JaSAn]

Ventilation is always a good idea in these small campers.

A couple of questions:
Do you find that the heater soots up when running on low heat setting?
Do you have temperature stratification without another fan moving air?

 

[Jsoboti]

Ventilation is always a good idea in these small campers.

A couple of questions:
Do you find that the heater soots up when running on low heat setting?
Do you have temperature stratification without another fan moving air?

I've only just started using the heater so I'm not sure how gross the combustion chamber is. All my research / videos online would suggest that running it at a low setting will soot up the chamber but then subsequently running it on high for 30-60 minutes should help clear it out.

I also leaned out the mixture significantly to adjust for high altitude, which should help with a complete burn and less soot. Throw spears if that's wrong please.

I noticed less temp. stratification than with the propane heater, the vent is pretty low, and the air comes out at a relatively high speed on the high settings so it felt to be a more uniformed temp. in the camper when compared to the dometic unit.

 

[Dan W]

Nice job on your swap out from propane to diesel. I've done the same thing on my Hawk but I kept it all in the propane heater space. I ran the exhaust out the existing propane heater exhaust port. I'm using a stainless steel 1 and 1/2 gallon tank that sits between the cab and attached to the camper. I will use the remaining space in my propane box after removing one tank for my Reserve diesel. So far it's working good and we are happy with the change. I split the Box in half and have the heater sitting on the top shelf. I've learned quite a bit on this form from all of you thank you so much for your input.

 

[Dan W]

This photo was taken right before completion. There's a piece that slides in after you slide the heater in to semi seal it off more from the lower chamber. What I've learned was not to completely seal it off from the bottom chamber due to heat buildup. I considered putting a fan in with an exhaust port either outside or inside. As of right now it's working good but anything over 60°f outside during testing caused it into a E5 code meaning overheating in the chamber. When I tested it even in direct sunlight with an ambient outside temperature of 42 it ran fine and as long as we wanted.

 

[Jsoboti]

This photo was taken right before completion. There's a piece that slides in after you slide the heater in to semi seal it off more from the lower chamber. What I've learned was not to completely seal it off from the bottom chamber due to heat buildup. I considered putting a fan in with an exhaust port either outside or inside. As of right now it's working good but anything over 60°f outside during testing caused it into a E5 code meaning overheating in the chamber. When I tested it even in direct sunlight with an ambient outside temperature of 42 it ran fine and as long as we wanted.

Nice work, and you avoided cutting a 5 inch hole in your camper! I'll call that a win.

 

[Dirt Rider]

Decided since I never use my water heater it would be the perfect place for my diesel heater.

 

[Dan W]

Decided since I never use my water heater it would be the perfect place for my diesel heater.

 

[Dan W]

Dirt Rider, did you run the exhaust out through the existing hot water exhaust port? Are you concerned at all about having your exhaust even though it's wrapped touching the plywood? I purchased some aluminum back fiberglass sheeting that I put in places that I was concerned about heat issues and it does seem to help. When the sun was on the metal exterior housing of the heater it was up around 120°. When I put the fiberglass sheeting on it dropped it down to about 85.

 

[Dirt Rider]

I know its hard to see, but the wood was getting to hot so I put a piece of aluminum under it and under that high temp silicon. the exhaust is a high temp bulkhead fitting made for this type application. I will try and attach a pix.

 

[Dirt Rider]

 

[Dan W]

I know on my unit the temp was well over 300° at the elbow. I don't know that the aluminum is going to help that much because it'll probably transfer the heat but maybe keep it from burning. They do make an elbow that you can get on Amazon that might make it turn a little tighter so you're not making contact with the bottom. Changing the subject. I was having overheating problems but just found out that the motherboard and controller I have is working incorrectly. So the manufacturer is sending me a new motherboard and controller. Apparently it's a known issue. Keep working on it Dirt rider, tweaking and adjusting and you will get it.

 

[Dan W]

Dirt Rider after looking at your picture again, do you think there's any way you could cut out below the exhaust in the plywood? If you could give it a little breathing room so to speak would probably help out quite a bit.

 

[Dirt Rider]

Ran it all night and it is not showing any signs of getting to hot anymore, the aluminum and silicon did the trick.

 

[Vic Harder]

i ran the exhaust from my Propex heater through a 1" hole, with not much clearance around the exhaust tube. Sealed with red high temp silicone. No issues with the plywood getting hot.

 

[Dan W]

Vic, dirt rider, glad your systems are working good for you guys. I'm probably being over cautious by trying to keep my exhaust away from burnables. We have been traveling full time for almost 3 years from the tip of baja to the tip of Maine and down to Florida. When we were in cold weather up north in Wyoming we were ripping through the propane. Now I feel comfortable with having a heating system that's easier on fuel and I can pull up to a pump and take care of the truck and the heating oil. My goal was to be able to remove the propane heater and make a slide in mount for my diesel heater that I could remove easily for maintenance and repair.

 

[Vic Harder]

Dan, I totally agree with you re: fuel and getting it all at once. Glad it is working for you, and your pioneering work with cheap CDH's will be helpful for the rest of us...