CNG to Propane Conversion [Master Thread]

GrandpaSteve

Sustaining Member
There should be a stainless safety rail running in front of the stove. I installed the panel just to the right of the right end of that rail, where shown in the attached picture. The factory wiring diagram shows a gray wire (maybe with white stripe?) for the "Stove" circuit from the DC panel. I found two coils of wire fitting that description, one near the factory propane locker at the stern, and another in the area of the tilt-out plate cabinet, so it was just a matter of making connections with new stuff in those two areas. The stove circuit breaker can energize the Xintex panel, and that panel controls the solenoid valve.

If you install your panel is that same location, be sure and allow space for the large diameter "nut" to go onto the rear of the Xintrex. The ice box is very close by.


View attachment 44441
I have to find those wires.
 

Prairie Schooner

Jeff & Donna, E35-3 purchased 7/21
Thanks @peaman - that location worked out perfectly. Never mind that I thought I could get away with a 2 1/8" hole saw for the Fireboy Xintex LPG control panel (when the box and instructions clearly said 2 1/16"). Let's just say that my control panel is more of a flush mount into the cabinetry of the 32-3. And, wait, where does one even buy a 2 1/16" hole saw?! Don't answer that... more important question below

I've been trying to avoid buying a few more parts and I staged this configuration today. I can't find anything in the manual for the solenoid valve about mounting position. There's clearance at the top for the pressure gauge and enough room at the bottom to join the appliance LPG hose at the bottom. Can anyone see anything wrong with this setup?

View attachment 44663
Hi Bryan,
We're heading into this project. How did this arrangement work for you? Is it documented elsewhere here? Is there anything you'd do differently?
Thanks, Jeff
 

vanilladuck

E32-3 / San Francisco
Blogs Author
Hi Bryan,
We're heading into this project. How did this arrangement work for you? Is it documented elsewhere here? Is there anything you'd do differently?
Thanks, Jeff

Ahoy, Jeff! I took a lot of photos but didn't document much... yet. If it would be helpful I could write a quick blog article detailing my process and the results?

I changed a few things with my setup from the photos previously in this thread.

The toughest thing I remember was pulling the LPG hose and sniffer sensor cable through the hose-conduit between the galley and the starboard lazarette.

The one thing I would change is buying a slightly longer LPG hose. Per ABYC guidelines they are pre-measured and pre-terminated with NPT connectors. Having one a little longer would have allowed for better "dressing in" high in the laz...
- Bryan
 

Prairie Schooner

Jeff & Donna, E35-3 purchased 7/21
Ahoy, Jeff! I took a lot of photos but didn't document much... yet. If it would be helpful I could write a quick blog article detailing my process and the results?

I changed a few things with my setup from the photos previously in this thread.

The toughest thing I remember was pulling the LPG hose and sniffer sensor cable through the hose-conduit between the galley and the starboard lazarette.

The one thing I would change is buying a slightly longer LPG hose. Per ABYC guidelines they are pre-measured and pre-terminated with NPT connectors. Having one a little longer would have allowed for better "dressing in" high in the laz...
- Bryan
Thanks, Bryan. That info is helpful and I'd appreciate any more you could put on the site for what you did. @peaman has already been a great help. I'm an almost pathological gatherer of perspectives before I commit to a plan.

I found a new Force 10 on Craigslist, along with much of the needed gear. So, we've got that going for us. It's the bigger Trident control unit, but it does both sniffer control and on/off.
stove Force 10_5410.jpg
 

Prairie Schooner

Jeff & Donna, E35-3 purchased 7/21
Ahoy, Jeff! I took a lot of photos but didn't document much... yet. If it would be helpful I could write a quick blog article detailing my process and the results?

I changed a few things with my setup from the photos previously in this thread.

The toughest thing I remember was pulling the LPG hose and sniffer sensor cable through the hose-conduit between the galley and the starboard lazarette.

The one thing I would change is buying a slightly longer LPG hose. Per ABYC guidelines they are pre-measured and pre-terminated with NPT connectors. Having one a little longer would have allowed for better "dressing in" high in the laz...
- Bryan
Hi Bryan,
I measured the boat today and it's about 11' from the stove to the propane well. A 15' hose would leave a couple feet on each end to neaten the install. If it were you, would you bump up to a 20 footer? Anyone else is welcome to chime in, too. Is there a disadvantage to having a big loop in there?
Thanks,
Jeff
 

peaman

Sustaining Member
You want to have adequate extra at the gimbaled stove end for an easy and full swing, and you want enough to make the distance to the propane locker, without needing to stretch or kink in any way, along a convenient path. Anything more than that will offer no advantages. It's not like line or wiring, or common tubing that you might want to cut off a bit and re-terminate later on. The factory-made end fittings are there to stay, and I doubt you would want to replace either end without replacing the entire length.
 

Prairie Schooner

Jeff & Donna, E35-3 purchased 7/21
You want to have adequate extra at the gimbaled stove end for an easy and full swing, and you want enough to make the distance to the propane locker, without needing to stretch or kink in any way, along a convenient path. Anything more than that will offer no advantages. It's not like line or wiring, or common tubing that you might want to cut off a bit and re-terminate later on. The factory-made end fittings are there to stay, and I doubt you would want to replace either end without replacing the entire length.
I think 15' would accomplish all that once installed. Per Bryan's comments, I was wondering if a little extra would make installation easier. And, that accomplished, is there any downside to having extra that is looped up and stored out of way? A loop should fit nicely between the propane tank well and the starboard quarter. And nothing else can be conveniently stored there. If I were to order custom hose, I'd get 17.5'. I think I'll wait until I pull the old hose out and measure it. Your idea of using a drilled fitting is pure gold.
 

Nick J

Contributing Partner
Moderator
Blogs Author
I just looked at my order and was surprised to find I used a 25' hose! I can't remember how much slack I had to store, but it fit well under the starboard cockpit coming. I'm headed down there after work. If I remeber I'll take a pick.
 

vanilladuck

E32-3 / San Francisco
Blogs Author
I ordered a 15' hose for my install and it reached, but with no slack. This is probably due to the path not being a very straight line between the galley and the propane locker. There's not enough leftover hose to zip-tie high in the starboard lazarette, so it lays on the shelf where the CNG tank used to mount.

A 20' hose would be perfect -- and I don't think there's anything wrong with having a bit of a service loop as long as it's lashed/zip-tied down well.

FYI: Pulling the hose through the flex conduit was not an easy task. Once I got the hose in place, I didn't want to change it out ;)
 

lightbulbjb

Junior Member
Thanks, Bryan. That info is helpful and I'd appreciate any more you could put on the site for what you did. @peaman has already been a great help. I'm an almost pathological gatherer of perspectives before I commit to a plan.

I found a new Force 10 on Craigslist, along with much of the needed gear. So, we've got that going for us. It's the bigger Trident control unit, but it does both sniffer control and on/off.
View attachment 49128
How in the world did you manage this?! Crazy luck? I saw one on fb marketplace pop up this morning and it was gone within an hour or two. Owner never even responded to me before marking it sold.
 

lightbulbjb

Junior Member
Honest question, possibly ignorant: is there a functional/practical difference between the LPG tanks peaman mentioned and a normal BBQ grill tank? Is there a specific reason to avoid the latter (assuming they fit in the propane locker)? I know I can get replacement BBQ cylinders at the gas station - where does one fill the fancier kind?
 

Prairie Schooner

Jeff & Donna, E35-3 purchased 7/21
Honest question, possibly ignorant: is there a functional/practical difference between the LPG tanks peaman mentioned and a normal BBQ grill tank? Is there a specific reason to avoid the latter (assuming they fit in the propane locker)? I know I can get replacement BBQ cylinders at the gas station - where does one fill the fancier kind?
I've been doing some research on this. I don't think the standard grill size will fit in our Ericson locker. I didn't find anything about marine grade propane tanks, though it might be something I missed. The main thing seems to be assuring they are DOT certified. We got a small one with the stove purchase, maybe 6-7#. I'm looking for a second one, tho as big as will fit in the locker. They're available on Amazon and there were some competitively priced in the Defender spring sale. Some folks prioritize weight and/or rust resistance in their decisions. Steel, aluminum, and fiberglass seem to be the predominant materials. And that's all I know about that.
 

peaman

Sustaining Member
Prairie Schooner is right. A "normal BBQ grill tank" holds 20# of propane. Many of us have a factory-built propane locker which does not have the diameter capacity for a 20# tank. My own boat, 1987 32-3, can hold either of the two tanks I mentioned, one of which is steel and the other is aluminum. Trade-off considerations are tank weight, propane capacity, purchase cost, and corrosion issues. I expect any tank marketed or refillable for propane will be DOT approved, and expected to have been pressure tested within the allowed period.

Worthington Enterprises manufactures many different size tanks in both steel and aluminum.

If your propane locker can hold a 20# tank, go for it. Any place that can refill a tank, versus swap full for empty, should be able to refill any refillable tank. One-pound tanks are not refillable. I generally take mine to a local agriculture and garden supply store for refill.

Be aware that a propane locker on a boat should be sealed when closed, and should have a gravity drain to atmosphere above the boat's waterline, among other requirements. Cutting corners in installation and maintenance of propane systems on boats has resulted in some spectacular explosions.
 

lightbulbjb

Junior Member
Prairie Schooner is right. A "normal BBQ grill tank" holds 20# of propane. Many of us have a factory-built propane locker which does not have the diameter capacity for a 20# tank. My own boat, 1987 32-3, can hold either of the two tanks I mentioned, one of which is steel and the other is aluminum. Trade-off considerations are tank weight, propane capacity, purchase cost, and corrosion issues. I expect any tank marketed or refillable for propane will be DOT approved, and expected to have been pressure tested within the allowed period.

Worthington Enterprises manufactures many different size tanks in both steel and aluminum.

If your propane locker can hold a 20# tank, go for it. Any place that can refill a tank, versus swap full for empty, should be able to refill any refillable tank. One-pound tanks are not refillable. I generally take mine to a local agriculture and garden supply store for refill.

Be aware that a propane locker on a boat should be sealed when closed, and should have a gravity drain to atmosphere above the boat's waterline, among other requirements. Cutting corners in installation and maintenance of propane systems on boats has resulted in some spectacular explosions.
That makes a lot of sense - thank you! I also have the manufacturer-built propane locker, but hadn't thought to check if a BBQ tank would fit.

Regarding the "gravity drain to atmosphere" etc - is the manufacturer-built locker typically set up that way by default, or is this something I would need to take on myself? I will double check and verify, regardless.

What did you use to pass solenoid wires out of the locker? I can't seem to find any vapor tight straight-thrus for wires, just hoses and not sure what the right answer is.
 

vanilladuck

E32-3 / San Francisco
Blogs Author
Regarding the "gravity drain to atmosphere" etc - is the manufacturer-built locker typically set up that way by default, or is this something I would need to take on myself? I will double check and verify, regardless.
I don't have a good photo of the underside of the propane locker, but you should have a fitted hole in the bottom-center of the locker. If you open the other aft lazerette, hopefully you have a hose connecting that hole to a thru-hull close by. If you have no thru-hull, you'll have to put one in (which is slightly beyond my current capabilities). Maybe there's one there and all you need to do is put a hose with double hose clamps on each side.
 

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