LP Regulator Operation Explained

[2825Matheny]

The following is an edited version of 2825Matheny's original post here. His post was in response to a question on how the automatic change-over valve/regulator works--it's the best explanation I've read on the subject to date. -Moderator Howard
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Yes, there are two tanks. On a FW the tanks are on opposite sides of the trailer. On a TT they sit side-by-side on the tongue of the trailer. Since you have an Imagine let's talk only about TT's for the time being.

For terminology purposes, the primary tank is the tank that the handle on the auto change-over valve/regulator (ACOVR) valve is pointing to.

The ACOVR is a bit confusing. For the features of this valve/regulator to work, BOTH of the Over-fill Protection Device (OPD) valves on the tops of both tanks need to be OPEN. The handle on the ACOVR points to the tank you desire to be your primary tank which propane gas is drawn out of. With the handle pointing to a full tank, the indicator on the ACOVR is GREEN indicating life is good and you have gas. You can choose either tank to be your primary tank.

Then after a period of use, the primary tank will become empty. When that happens the ACOVR does two things.

First, it internally stops drawing propane from the primary tank, because there isn't any, and it starts drawing gas out of the backup tank. Second, the GREEN indicator turns RED to inform you that your primary tank is empty. The handle does not change positions on its own.

So the first lesson about tank management is to check the indicator now and then so you know when the primary tank goes empty. If you don't, then you can expect to empty both tanks and you will be without propane gas until you refill. This is not something you want to happen in the middle of the night when its chilly outside.

Once you notice that the indicator is RED, manually rotate the handle to point to the other tank. Assuming that tank is still full, the indicator should now change from RED to GREEN and the full tank is now your primary tank. At this time you should shut off the OPD valve on the top of the empty tank, disconnect the pig-tail hose, remove the cylinder from the rig and take it to be refilled.

Once you refill the cylinder, install it back in the rig, reconnect the pig-tail hose, and open the OPD valve on the tank. Do NOT manually rotate the handle on the ACOVR valve at this time. Leave it pointing to the tank that was in service while you filled the empty tank.

Now the indicator on the ACOVR is monitoring gas pressure from the primary tank and the tank you just got refilled is your backup and its ready, willing, and able to go into service when your primary tank goes empty. This cycle just repeats over time as tanks go empty.
Just remember to check the indicator now and then to know when your primary tank is empty so you don't get caught with two empty tanks at the same time.

A few pointers about LP cylinders and refilling them.
Do NOT lay a tank on its side. It's a safety thing. Stand it up in the bed of your truck and use a cargo strap going from side to side to cinch it down so it doesn't fall over.
You can refill a tank at many places. Campgrounds, propane dealerships, Tractors Supply. Some charge by the gallon. Some charge a flat rate, so if you take a partially full tank to have it topped off they will try to charge you as they would to refill a tank that was completely empty. Negotiate with them.
A typical 30 Lb tank holds about 7.1 gallons of liquid propane.

A FW has an extra regulator on the curbside tank. This is to reduce the pressure of the propane gas in the hose that crosses from the curbside to the roadside of the rig. It's a safety thing. They don't want high-pressure gas being piped through your rig in a hose. That regulator is a 30 psi regulator.

[Najataagihe]

I put a copy of an outstanding post explaining the operation in the Reference Library--please give it a read! https://www.mygrandrv.com/fo...tion-Explained

Good read, but there is one thing I have not seen anyone mention.


If you put the regulator selection switch in the MIDDLE position, it draws from both tanks at the same time, thus the warning to pick one of the other lest you run totally out of fuel at an inopportune time.

[howson]

Good read, but there is one thing I have not seen anyone mention.


If you put the regulator selection switch in the MIDDLE position, it draws from both tanks at the same time, thus the warning to pick one of the other lest you run totally out of fuel at an inopportune time.

Copied this to the Reference Library thread. (Thanks for the input!)

-Howard