We frequently see questions from both new and experienced owners asking how to modify their gas grill or stove to run on their existing trailer propane system. The responses usually contain a lot of information, usually good, but sometimes not so good. A short time back I responded to one of these threads and later received a request from a forum member to make it into a sticky. After receiving the blessings of the Moderators, I decided to put everything I have learned, both through personal experience, reading and talking to the parts people at the dealerships.
Propane Basics- All of your trailers gas appliances run on low pressure propane. This pressure is regulated at the tanks to 11"WC. This pressure is measured with a manometer and there have been occasional threads on how to make your own, but that's beyond the scope of this post. What you need to know is that the propane in your trailer is kept at a constant pressure.
Stoves & Grills - With a few exceptions, when you buy a propane grill or stove it is going to have a self contained regulator and is intended to operte on high pressure systems, either connected to a supply tank, which can vary in size from one pound to 30 lb., or connected to the high pressure or input side of the regulator on your trailer's system. If you choose the latter, you are pretty much limited to the aftermarket products that let you "tap" into the output of the tanks and is pretty much a permanent installation. Many people use this type of setup without issue, but my personal preference is to not introduce any more fittings to the system than necessary. The more fittings and connections you have, the more chance there is of developing a leak or other such problem, so I just think it's better to keep it simple. JMHO.
If you are reading threads on this forum, more than likely you own a Keystone trailer of 5th wheel. And more than likely, it is equipped with an outdoor kitchen of some configuration. If that is the case, you already have a suitable supply of low pressure propane ready to connect to that new stove or grill. Now the problem, as I stated above, is that most propane appliances are going to have a self contained regulator. The problem is that you can not regulate the pressure twice, because the result will be not enough pressure. You have a choice, you can either use one of the aftermarket high pressure adapters, or you can remove the regulator on the grill and fit it with a quick connect fitting that will allow the use of your existing low pressure propane system. This leads us to the real topic of this article, converting your appliance to work on low pressure.
Grills - I'm going to limit this discussion to the Weber grills, mainly because they are an extremely popular brand and it's the one with which I have actual experience. The procedures discussed here will most likely be applicable to about any brand out there with the exception of Coleman. I have not been able to verify this, but I've read from more than one source that Coleman uses a proprietary thread size for their grill and stove fittings. So far no one has posted that they have knowledge of the thread sizes and Coleman will not disclose it. I did read a post from one owner that he cut the regulator off the stove and attached a hose using a hose clamp and it has worked for years without issue. That would not be my choice, but you have to decide if that will work for you, or if you should look for a grill that is more suited to this conversion. For you Coleman users, there are hoses available that allow you to connect the stove to a large bottle or to an adapter that connects between the house propane tank and the regulator. I've not used one of these adapters, so my only advice is to check any connections that are going to be permanent with a soap solution for leaks. You can also get an adapter that will allow you to refill the small disposable bottles. Keep in mind that these bottles use a plunger type system for opening and closing and have been known to leak after several fillings, so be sure that you store these outside and not inside the trailer.
The regulator/control assemblies on most grills are going to be of similar construction. You are going to find a regulator, screwed into a valve assembly. On the Webers, and most other brands, this is going to be 1/8" NPT thread. The thread size of the QC nipple is going to be either 1/4" or 3/8", depending on what you buy. Either will work, but 1/4" seems to be pretty standard. You'll need an adapter with 1/8" male/ 1/4" female. The male nipple for the QC is going to be male threads. When yo put gas fittings together, remember that you use yellow thread tape for gas. The white teflon tape that you use for air fittings will break down with exposure to petroleum product, including propane.
In the even you end up with flare fittings, only pipe threads get taped, flare fittings are assembled bare. Unless you have access to flare tools and have worked with them, you'll most likely end up using all screw type contours.
Quick Connectors - Here is where someone is going to say,"i've used them for years and they work fine". They are referring to standard air compressor fittings that you buy at Home Depot and Lowes. These are not suitable for flammable gas use. Regardless of what anyone tells you, they leak. Propane is heavier than air. What this means is that if you have a propane leak, without a breeze to disperse it, gas will accumulate in a low spot or pocket under your trailer waiting for a spark, and if that happens the result will not be good. Propane is a dangerous gas, but proper handling will go a long way towards preventing accidents. The point here is that if you are going to go cheap on something, do it on the water regulator if you have to, not propane fittings and connectors.
The Hose - You will need a length of suitable propane hose to connect your grill to the trailers QC. The fitting on the trailer is female, so it obviously has to be a male nipple. If you are buying a QC in a set of male and female, there is no compatibility issue, however, if you are looking to match one piece with another, be aware there can be some compatibility issues and you can waste a lot of time and money looking for the right part.
Keystone uses QCs made by Fairview. It's a common brand and is available everywhere online. As far as what piece goes where, I recommend putting the male fitting on the stove or grill. The reason is that you are going to have limited space near the control assembly and it's easier to manipulate the female fitting if it's on the end of a hose rather than attached to the grill. Another reason is that this gives the layout of female/male/female/male and there is never a question which end connects to the trailer, which can be problematic if you happened to mix brands of connectors that are not mechanically compatible.
On brand compatibility, be aware that there are high pressure and low pressure quick connect fittings. Since you are dealing with low pressure propane, either will work, but male and female fittings won't be compatible even if they are the same brand. Don't ask me how I found this out. if you are just putting together a hose to use a single appliance, then use any complete set for the stove end and be sure to get a compatible nipple for the trailer end. As far as compatibility, I have very limited info on that. I do know that Olympian/Camco is compatible with Fairview. FWIW, Mr Heater is not compatible with anything but another Mr Heater component, so if you are setting up for multiple appliances, I would steer clear of those. Other than that, a low pressure nipple should fit a low pressure nipple., but it's always better to get a part number of the fitting you are trying to match and go about it that way. Every fitting is going to have a number stamped on it, and a good propane guy will be able to help you with what you need. The main thing is just don't try to match HP and LP connectors, I promise it will be an exercise in futility.
Brand compatibility - To my knowledge, Mr Heater parts do not work with anything but Mr Heater appliances. Hansen is compatible with MB Sturgis and with Fairview(Keystone trailers. Olympian/Camco works with Fairview. If any one knows of others, please let me know.
In conclusion - The information here is correct to the best of my knowledge, but I'm human too, so don't shoot the messenger. Instead, send me a PM with corrections or information on part numbers, compatibility or sources, so I can edit this post, or post a response with a correction. It won't hurt my feelings and everyone benefits from good information.
Below are some photos of how all of this should look when you get finished, and hopefully, this will help someone get a little closer to grilling those rib-eyes or frying that batch of fish.
I did run across a couple of good sources for propane fittings and hoses, so with the Mod's permission, I'll post them here.
Home Depot and Lowes carry some of the more standard brass fittings as do most plumbing stores
While I encourage anyone to post relevant information and corrects, I would encourage our members to not turn this into a "my brother told me" thread. Lets try to keep it on topic.
Link to Coleman Road Trip Conversion