LP tank gauges - Do they work?

[C Schomer]

My dual tank auto changeover valve worked properly until it ran out of warranty! Now both tanks go empty without the indicator ever going red or switching the handle to the second tank. Do any of the magnetic level/temp gauges work very well? Does the tank need to actually be delivering fuel to have enough temp difference on the side for them to work? I can't see replacing the valve because this isn't the first one that's quit on me. TIA! Craig

 

[ZEEEW]

We have a stickon strip, pour hot water on the strip area, the water heats the metal tank, and does ok at showing liquid level. Where the liquid starts the tank doesnt heat up, liquid is a heatsink so to speak. You should be able to get a reasonable idea of level by looking at the frostline on the tank, if you are drawing enough fluid.

 

[C Schomer]

Thanks ZEEEW, I'll try that. I've never used enough fuel to drop the tank temp to the frost point. Also, I'm usually in the mountains(VERY dry air) where the frost point is WAY low. I knew there was a trick to making the strips work better - I forgot it was the hot water! Craig

 

[Loren]

Craig,



It sounds like your auto-changeover regulator is not working properly. For it to work properly you must:

1. Be sure both tank valves are open.

2. Do not switch the SERVICE indicator until the indicator shows that one tank is empty.



The changeover regulator is meant to work as follows:

1. You install two full LP gas tanks, and open the valves on both of them.

2. Your appliances use LP gas. The gas you are using will be delivered from the tank that the arrow on the SERVICE indicator points to.

3. Eventually that tank will become empty and the regulator will start delivering gas from the other tank. When that happens, the red indicator will pop into view.

4. You close the valve on the empty tank (the one the SERVICE indicator points to). Then you switch the SERVICE indicator to the other tank by rotating the knob, or flipping the paddle, depending on the type you have. As you switch the SERVICE indicator the red indicator will disappear.

5. You then remove the empty tank, have it filled, and reinstall it. If gas escapes at any time during this operation, you haven't followed these steps in the correct order.

6. You open the valve on the tank you just installed. DO NOT switch the SERVICE indicator until the OTHER tank is empty. At that time you will do this all over again for the other tank.



You can check the changeover operation easily. Here's how:

1. Install two tanks that have fuel in each of them. Open the valves on both tanks.

2. Select either tank with the SERVICE selector.

3. Start the furnace, water heater (on gas), or other major LP gas consuming appliance in the RV.

4. Close the tank valve on the LP tank that is indicated by the SERVICE arrow. That is, shut off the gas on the tank that the arrow points to.

5. Within a few minutes the red indicator should pop into view. If it doesn't, and the gas continues to flow then you know that the regulator switched, but the red indicator didn't show it. If the gas doesn't continue to flow, you know that the switch didn't occur. In either case, your auto-changeover feature isn't working properly. I would replace the entire unit.



As far as gauges on LP gas tanks are concerned, there are two basic types, floats and temperature types. The floats are pretty easy to understand. They have a float on a spiral shaft. The float rides up and down on the surface of the liquid in the tank. The spiral shaft turns a pointer on a gauge.



For the temperature types to work you must be using gas from that tank. You have a changeover regulator and will be using gas from only one tank at a time (if it's working). The principle behind a temperature type gauge is that the liquid LP gets cold as it boils to supply gaseous LP to the RV. If you pour water (especially hot water as stated) against an LP tank that is supplying a major appliance, some of the water will actually freeze against the lower portion of the tank. The top of the ice is the top of the liquid inside. The temperature of the liquid inside will depend on how fast you are using gas (boiling the liquid).



Commercial temperature-type gauges use this same principle, they just indicate the temperature difference with color changes or other mechanism. You must be using gas for this type of gauge to work.



I know this is more than you asked for, and probably more than you need, Craig, but maybe someone else has the same question.



Loren

 

[C Schomer]

Loren, everything worked right the first few tanks then the gauge stopped going to red. It ran the service tank empty and auto switched to the second tank without changing the lever but the gauge didn't turn this time. I thought I ran all of 2001 on one tank but when I checked, the backup tank was almost empty. I think something got sticky with the gauge. Too bad they don't come apart to lube things! Craig