LP automatic change over

[uncle_bob]

Hi

On some trailers, the tank monitoring stuff comes "stock". Even with the status up on a display right over the dinette, I don't really trust the system. That's based on input from a neighbor who also is an Airstream owner. We run the same way he does.

One tank is shut off (with the valve) and we run from the other. When that tank gets close to empty, we open the valve on the full tank. The switchover (eventually) flips over to the full tank. Once the flip has happened, the valve on the empty tank is shut.

Since both tanks are identical in size, they both have the same amount of propane in them. (Indeed it depends a bit on how they get filled). Running on one vs running on the other does not matter in our case. We fill the empty when we get a chance and move on.

Bob

[Mollysdad]

This should be explained at the walkthrough, if the tech doing the walkthrough actually knows the in's and out's. My guess is you'll get a generic, "It's automatic."
I thought one of my tanks was low, just from wiggling it. When I turned off the tank valve, the monitor went from green to red. I opened the valve and it went back to green. I still don't know exactly why it acted this way. It appears I was operating from the tank in question. You have to actually play with it to understand.

[nickcrowhurst]

The understandable confusion occurs because the red/green flag is only telling you whether or not the tank towards which the lever is pointed has some propane in it. It is not telling you that you have to do anything.
Green = there is propane remaining in the tank towards which the lever is pointed.
Red = the tank towards which the lever is pointed is empty, and now, if you wish, you can turn the lever to point to the other tank, tank 2. If you do, the flag will go green if there is propane in tank 2. Also, if you wish, you can then shut off the valve in tank 1, disconnect it and take it to be re-filled.

That's how I've understood and used the system for the past 20 years. The counter-intuitive aspect of the system is that one expects a red flag to mean that you have to take some action. You don't, but you can if you wish.
Mollysdad's system is working correctly.
The change-over of supply from the empty tank to the other tank with propane in it is automatic and needs no human action.
Nick.

[AirMiles]

Originally Posted by TBRich

The changeover works in either direction. Just keep an eye on the green/red indicator and when it turns red switch to the other tank and it will immediately turn green. No need to physically switch the tanks...just turn off the one that's empty and remove it to refill...the trailer will continue to use from the remaining tank. After refilling re-install the tank and open the valve...and you are good to go.

Thank you for sharing this. I will begin using the automatic change over in both directions. I use 20# exchange tanks (typically only filled with 15#) so I replace one every 10 days or so when camping. This knowledge will save me from frequently juggling my tanks around. I was hoping someone with experience would reply if the change over worked in both directions.

[Airlock]

According to the 2019 AS owners' manual: "All models are equipped with a two stage automatic change-over gas regulator that offers the convenience of automatic changeover from empty to full gas cylinders. Both tanks are connected to this regulator." The manual goes on to say to select any tank you wish as the "service" tank; do this by rotating the white knob on the top front side of the tank towards the tank you wish to use first. The other tank then becomes the "reserve" tank. For the automatic change over to work you must open both valves when you are going to be using propane. When propane stops flowing from the tank you've selected as the "service" tank, the regulator will automatically start the flow of propane from the "reserve" tank. Now the tank indicator on the "service" tank will be RED. Take that tank and have it filled. That's it.