Hi all - 

Yes, I'm a King of the Hill fan!  I'm going to post here directly a picture of my propane tank, and regulator - I'm not even sure there's enough room to squeeze in a bypass kit, but in the interim I want to see if I'm even thinking about this correctly.

What I want out of the bypass is to tie in a Mr Heater (the smaller one you can't plumb in to the low pressure lines).

I found this, but it seems to be something for hooking up to an external propane tank (which would be nice to have ADDITIONALLY, but first priority is to use the onboard for the Mr. Heater). 



Then this was going to be the kit for the Mr. Heater to string it to the bypass:


My only issue with external is I have nowhere to really carry a tank.  The bay isn't tall enough, The shower is already dedicated to the catbox and the laundry basket while in motion (and I don't really like the idea of keeping it inside) which leaves mounting somehow on the back tool box and wouldn't know where to begin for that - is it even legal?  Of course I could just get tanks when and where I needed them - put down deposit, take a quick trip to where I'm setting up and leave it out until ready to leave area and then return to get my deposit back.  I've heard there are smaller pancake ones but they don't seem to be common, easy to find.  

I promise a blog post soon - doing a lot of little details right now and goes back for final mechanic work Monday; then when back I'll be on the home stretch!

Tags: bypass, heater, mr., propane

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Good morning, Dawn Michelle; 

     It has been a couple of days now, and there is no written response to your inquiry.  Interesting. 

     In the examination of the equipment available, it does look like the main use for the Stanbroil "Tee" adapter and similar devices seems to be attaching an external propane tank to provide a supplemental source for propane in addition to the main propane tank in the RV.  The Marshall "Extend-a-Stay" products seem to be similar.  It is possible that a few of the adapters may have a one-way check valve to limit the direction of propane flow through the system.  Many of them also have some sort of restriction to limit the flow rate through the system.  There are a couple of pounds of brass adapters and fittings here now, but I have not yet been able to find a combination of them that will allow me to do what I want to do with my RV propane system.  The makers seem to have some clearly "one way" ideas on how they want their systems to be used.  It looks like I need to do some more searching on this subject.  While they do seem to allow the connection of both a propane cylinder for supplemental fuel, and for a propane appliance for use outside of the RV, that flow restriction does seem to be there. 

     Regarding carrying additional propane cylinders, yes, I also carry mine on the outside only, and they are carried on a rack that mounts on the back of the motor home in the 2 inch square tube trailer hitch receiver.  This is something that I do mainly in the winter when I know the propane consumption will be higher.  That also means that it may not be possible to drive through tunnels.  There are some additional plugs and caps that fit on the propane cylinder connectors to limit any leakage past the valve.  There is also a hope that those plugs and caps will reduce the probability of gas being released if a motor vehicle accident happens.  Not a nice thought, true, but I am hoping that this does help if that situation is encountered.  At least they are in the back, and that should reduce the velocity differential if something does happen.   I have also carried gasoline containers back there, and that is probably more hazardous than DOT propane cylinders.  For some of the places where I go, there are no convenient gas stations nearby, and I have provided fuel to vehicles that might not make it back out to a gas station. 

          Enjoy;  Ralph, Latté Land, Washington 

The configuration that your trying to achieve poses a pickle of sorts like Ralph described.

I contacted several of my old timers who have been RVing ,even before the wild west was settled and as Ralph pointed out, Alot of these Adapters have one way check valves and pressure regulators.

After debated discussion,, We agreed that, with a little creative thinking you Can configure a direct pressure off a  propane tank,(((( *NOW TAKE NOTE,  We all agreed your on your own safety wise and to double check with a propane distributor with the concept) With the correct fittings, such as from hardware store,H/D, Lowes etc, You can get a T fitting installed AFTER connection to the tank and BEFORE the regulator, And of Course integrating a shut off valve for the direct feed line. As far as transporting and mounting additional tanks,, The rear bumper is an appropriate place, Making a cylinder bracket isnt rocket science,,just a little elbow grease and imagination. Never transport additional tanks INSIDE the RV, Or even loosely in the back of a Vehicle,  To be blunt and not to throw a wrench in your concept,, I myself would use the appliance per manufacturers recommendations,, and if you still choose to take on this project,, a quick stop at a reputable RV shop or a Propane company, (not those small fill stations), But an actual compressed gas company,

Evening Ralph and Lakota :-)

Leave it to me to ask questions that create some head scratching.  

I think I just have to make some choices, and the first thing I have to decide is if I even want to risk running a high pressure propane line into the RV whether from an external tank or tapping into the existing system before the regulator.  

I'm thinking I just need to accept my purchase was a bad one, and go buy the next version up which will let me tap into a low pressure line and then try to figure out how to run it so I'm not tripping over the darn hose.  Or spend more money and get a wave if I could figure out where to install it.  

Thanks for the responses - I'll keep digging and at some point let you know my solution :-)

I have another RV tank that I've kept for quite some time that was an under mount type. My plan was to find another spot on the frame to mount it and have a back up tank to use in case of emergency but I haven't figured out 1) where to mount it on the frame; 2) how do I connect it to the existing gas lines and keep things safe; 3) is all the effort worth it?

I think you hit the nail on the head with #3.  That could apply to any project...

#2 - couldn't you attach it with the extend a stay option?  If you can tie in a bbq style tank that way, it seems you could as well with the one you are mounting?

I do like your idea - can see why you held onto it.

I did find a low pressure wave unit I like: https://www.amazon.com/dp/B000BUV1RK/_encoding=UTF8?coliid=I3B7BX8E...

For my situation I think that is going to be the most economical solution (in time, grief and money). At least for boondocking.  If I am plugged in I think I'd prefer to hook in the 20lb via the extend a stay and run the furnace. 


 This doesn't answer your question, but FWIW I bought a 12,000 BTU portable catalytic ventless Mr Heater I use ONLY in the mornings inside the RV long enough to take the chill off as its like twice as efficient as my forced air furnace. What I did was T into the soft roll 3/8 copper running to the fridge using flare fittings,,,,,,,,,From there I ran 3/8 stainless steel braided covered flex line to a wall near the heater with a yellow LP Gas approved Gate Valve for On/Off.  Then I ran another 3/8 SS braided line to the heater and installed an adapter to mate with the small 1 inch LP Gas bottle fitting in the Mr Heater. The flex line and extra length lets me sit it in the floor and move it around. The Heater has a low oxygen safety shut off plus I use not one but two LP detectors along with an CO sensor inside the RV and keep a nearby window cracked and NEVER run it overnight ONLY in the day when were there.

 For my LP supply (aux to main tank) I bought a Marshall Brass extend a stay fitting with an auto changeover valve and a piece of flex hose and OPD fitting which I screw onto my extra 30# LP Tank and use it till it runs dry then run on my main tank until I get the 30# refilled.

 I carry the 30# in the back of my pickup or Honda toad vehicle

 John T  

Hi John - 

Actually you are going in the direction I'm thinking.

I'm going to get the smaller wave catalytic I noted above and tie that into the low pressure lines with a tee - hoping I can do that off an existing connection so don't have to cut and flare, but watching videos, I could do that - just another tool to buy that only does one thing - LOL.  Then the little heater has a 3/8 sae male end...I'm HOPING that I can utilize that with a quick disconnect as my shutoff?  

That's my thinking at this point.  Refilling 1 lbs or running a high pressure line into the coach just seemed a bad idea.

I'll also probably add the extend a stay so that I have the option to add an external propane cylinder.  But for now since I'm going to be moving a lot anyway, refilling onboard tank won't be too big a chore.  

I may also see about mounting a cylinder rack to the back of the RV - the fixit guys did a great job with the ladder, so may see if they have a way to do that where I can still open the toolbox.  Or, I could buy an empty pancake that would fit in the bay if those can be refilled the same place where I refill my onboard?  Then I wouldn't have to worry about tunnels...

I had thought this fall I'd have electric hookups, but turns out where I can park is on the other side of the building than the outlets - that would be one dang long extension cord (plus all the loss I'd take).  So.  Trying to futz out that conundrum on how to recharge battery during day - I'm thinking a 100 watt solar panel in conjunction with 2-3 hours on a 1250 genny via the onboard converter might recoop my max 50 amps.  Or I could get a better external battery charger.  At least I can charge my electronics in the store that is letting me park there.  Then I could in theory just put the furnace on low and run it on the battery at night.  Insulate well with matting to put in the windows. 

Still thinking out loud.  I am worrying this like a dog with a bone, but I just want to make the most frugal decision I can that's going to meet my needs (conservation is going to be a big thing!)

  Dawn, do as you please, but I AM NOTTTTTTTTTTTTT A FAN OF A QUICK DISCONNECT IN MY LP GAS LINES but might consider one female outside like for hooking up a gas grill temporarily.......If I did have a quick disconnect INSIDE I would first and before it have a Yellow Gas approved On/Off gate valve.  I may be paranoid but I just don't trust quick disconnects INSIDE my RV. Those gas valves aren't expensive so I suggest it and then a quick disconnect for convenience and connection

 Cutting, flaring, installing a nut and T'ing into soft roll 3/8 copper tubing is fairly easy and almost idiot proof lol and Ive NEVER had one leak. I bought some 3/8 flexible stainless steel braid covered LP Gas line on E Bay and you can get it with 3/8 male or female NPT ends or other type threads, very easy and safe to use. You can also buy the brass adapter that screws into where the small 1 lb throw away bottles would go and plumb it to the flex line. All you need is a tubing cutter and a set of flaring tools, piece of cake into where the line fed my fridge then I cut a hole and ran the flex line inside to my gate valve. If there's already a T nearby you can scab an additional fitting onto it very easy. ONCE COMPLETED RUN A LEAK DOWN TEST and I use that spray on gas leak detector also. Always good to have an LP gas detector inside the RV, either an alarm type and they even make one that shuts the gas off if a leak is detected  


 How long it takes to replenish your battery bank up to 100% SOC depends on how much its depleted,,,,,,,,,the power of your charger and/or solar system and sunlight WELL DUH........Let me take a wild guess and say overnight your furnace or vent fans or lights consumed say 20 amp hours of energy. If you had a 20 amp charger it would take one hour of pumping 20 amps into your batteries (actually more due to inefficiency) to restore 20 amp hours. If you're gonna add a solar panel anyway its no harder to hang a 200 or 240 etc and you can buy them for 90 cents per watt so Id opt for at least a 200 watt panel. Then add a solar charge controller and hook its output to your battery bank and if the sun shines the next morning you're good to go in a short time SUBJECT to all the ratings.

 John T    

Once I've got her back in the yard I'll look for where I think I can tee in, and then get some pics.  All this input has given me a road map of what I'm looking for (thank you!) and what the project is going to entail.  I can at least go to the store and sound like I know what I'm talking about when I ask for stuff :-)

I wasn't ready to put panels on the roof - was going with a suitcase that's why the 100 watts.  Comes with a simple controller and was for just maintaining the cheap house battery that is up in the engine.  I can run it out into the sun when I'm in shade.  Later I was going to figure out the more complex idea of adding a battery bank under the dinette and wiring in rooftop solar. 

For now the systems are all hooked into the one in the engine and trying to wire solar to that seemed a giant step.  I thought I'd get my feet wet with baby steps!

I would do what John T mentioned, and I think I mentioned,, Have a Manual gas shut off before the quick disconnect,,, keep us posted,

Yes, you did!  Will do - it would be foolish to ask for advice and not take it :-)

 Dawn, my friends have the 100 watt suitcase style set out portable panels and they work great. I've found a 100 watt if moved a few times a day to keep pointed to the sun will harvest about as much as a 200 watt permanent flat mounted will. Those copper fittings are a T and three 3/8 inch flare nuts for soft roll copper tubing (3/8 is my guess of your size) any hardware store has them. If you do a search on E Bay look for stainless steel braided LP Gas Hose with whatever end fittings you need such as typical 1/4 NPT male or female I DID NOT find any of that at local hardware stores nor could I find the 1 inch adapters to mate into where the small disposable 1 lb cylinders attach in the Mr Heater, that's also E Bay stuff. Any good hardware store manager (NOT a teenage pencil necked pimpled geek) can show you the parts needed if you explain what you're doing. The Yellow (means for gas) handle Gas shut off valves are hardware store items and most have 1/2 female NPT ends for which you need adapters for the copper tube fittings and I use pipe sealer dope on ALL threaded connections.

 John T more of an electrician then a plumber lol so do what the "real" plumbers tell you   




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