Propane System Diagram and Research Solitude 3350RL

[Steven@147]

If you are not comfortable working on your propane system don't! Let the experts do it.

We recently had problems with a leaking main regulator (left side) and while working T/S the propane system I documented some things I learned. Then while reading a recent thread and an old thread from 2015 I decided to do a little more investigation. We do not have any more propane leaks (I bought a good propane sniffer to check for leaks) but the system is not working as it is supposed to. Our tank on the left side and pigtail to the main regulator, does not have a back flow preventer installed so if our right tank is on, it back flows to the left tank until pressure across the system equalizes. So whats happening is, if both tanks are turned on, propane is being used out of both tanks at the same time. This can be a bad situation if you think you have a full right side tank, then you find out you don't.

This happened to us. We had used our propane system for over a year and a half, always opening both tanks and running on the left tank as the primary, with the main regulator change knob pointing to the left tank. When we ran out of propane, I switch the valve over to the right tank only to find it was empty. I blamed having an empty right tank on a cheap dealership that zipped us on a full right tank. It wasn't the dealership, it was an improperly working propane system that I did not realize until just the other day.

I verified this by turning off both tanks, unplugged the left tank pigtail from the tank and had the wife turn on the right tank, I had propane coming out of the left pigtail. That should not happen. We did the same test reversing the process. Both tanks off, unplug right pigtail from tank, turn on left tank, NO flow out of pigtail because there is a back flow preventer installed on the right tank line where it goes into the main regulator. It doesn't matter what position the main regulator change valve is in. GDRV when they installed the propane system, removed or did not install, a left tank back flow valve on the main regulator, instead they installed a 90 degree elbow to make it easier to connect the left tank pigtail to the main regulator.

When we had our leak I changed the pigtails on both tanks because I thought that is where it was before I identified it was the main regulator. I did not realize all pigtails are not created equal. From my reading, the regulations require the pigtails to have an excess flow valve in case of a high flow leak and a thermal shut off for fire built into them, but not necessarily a back flow valve. From my reading of different manufacturers replacement pigtails, some DO have a back flow valve in the pigtail and some DO NOT. I had to read the detailed information to see that some do not come with a back flow valve.

When trying to get a replacement pigtail I got into this confusion of what color type 1 pigtail connector could be used on an RV. Light Green, Dark Green, Black or Red. Our original ones were light green. The only ones I could find at a local RV parts store at the time were dark green ones. I had a heck of a time finding information on colors of type 1 pigtails and when I did they didn't always agree. Some had the Light Green and Dark Green BTU/Hr ratings reversed. I needed to know if I could use a dark green one in place of a light green one, couldn't find that information. On my diagram I document the colors and BTU / Hr ranges of pigtails that I got from E-trailer. I assume they are correct, so yes I can use the dark green colored pigtail in place of a light green one because it will flow more propane. So if I were to use all the RV appliances on propane, H2O heater, Fridge, Furnace, stove/Oven the system can supply enough propane to run them all. If for example I used a pigtail with a black type 1 connector it could not flow enough propane to keep all the appliances running.

Also you have to watch out when replacing pigtails, they come in two flavors, 1/4 inverted flare and 1/4 NPT. I have both kinds installed by GDRV. When GDRV installed the left tank pigtail they used a 1/4 NPT because they used a 1/4 inch NPT 90 degree elbow screwed into the main regulator.
So long story short to fix our problem and get the propane system working correctly, I need to replace the 1/4 inch NPT 90 degree elbow with a 1/4 inch 90 degree elbow with an inverted flare, then install a back flow preventer inverted flare into that elbow. Then install a 1/4 inverted flare pigtail. OR buy a new 1/4 NPT pigtail with a back flow perventer manufactured into the pigtail.

I'll probably have to edit, need to get this posted before it times out and I lose it. forgive my crude diagram. Maybe my ramblings can help someone else, and if I get my assumptions wrong please chime in.