Propane Tank Level Indicator Error?

[RC-AV8R]

After two separate fill ups, our tank consistently reads at 1/3 full. I suspect a level sensor, but don't know what or how the gauge is sensing propane (ok - C3H8) level. Can anyone enlighten me on what I should check or is it a trip to the dealer next spring?

[Schmitte]

Originally Posted by RC-AV8R

After two separate fill ups, our tank consistently reads at 1/3 full. I suspect a level sensor, but don't know what or how the gauge is sensing propane (ok - C3H8) level. Can anyone enlighten me on what I should check or is it a trip to the dealer next spring?

I can’t answer your question but my sensor also seems off. It was reading 1/3 but only took 4 gallons of C3H8 so it must have been over 2/3’s full

[rmkrum]

The propane level sensor uses a variable resistor to sense level. One end of the resistor goes to your gauge panel. The other end connects to the tank body.

The problem is the body of the tank is not grounded solidly. Tighten the heck out of the tank hold-down and see if that helps any.

If you have a multimeter, check for voltage between the body of the tank and the metal of the A-frame. There should be as close to zero as the meter can read. If not, the tank is not well grounded...

In other threads, it was suggested adding a ground wire to the screw holding the sensor to the tank, and a two-prong connector to the tank so you get a solid ground for the gauge panel through one wire, and the other wire to the panel is well connected.

Another easy test: Pull the plug on your sensor and see if the gauge reads empty. Then ground that wire to the body or A-frame of the trailer. It probably will then read full. If it does, it's for sure a grounding problem.

Let us know what you find out...

[Titus]

My propane tank has a gauge that use instead of the electronic gauge.

[Alex AVI]

Originally Posted by rmkrum

The propane level sensor uses a variable resistor to sense level. One end of the resistor goes to your gauge panel. The other end connects to the tank body.

The problem is the body of the tank is not grounded solidly. Tighten the heck out of the tank hold-down and see if that helps any.

If you have a multimeter, check for voltage between the body of the tank and the metal of the A-frame. There should be as close to zero as the meter can read. If not, the tank is not well grounded...

In other threads, it was suggested adding a ground wire to the screw holding the sensor to the tank, and a two-prong connector to the tank so you get a solid ground for the gauge panel through one wire, and the other wire to the panel is well connected.

Another easy test: Pull the plug on your sensor and see if the gauge reads empty. Then ground that wire to the body or A-frame of the trailer. It probably will then read full. If it does, it's for sure a grounding problem.

Let us know what you find out...

RMKRUM - is the grounding issue affecting the physical gauge on tank or the virtual gauges on Firefly or SeeLevel display? My physical seems spot on but the virtuals are off, like 1/8-1/4 (lesser than physical).

[eubank]

A nice, vivid example of why fillers are not permitted to fill cylinders based on what such gauges read.

Lynn

[rmkrum]

Originally Posted by Alex AVI

RMKRUM - is the grounding issue affecting the physical gauge on tank or the virtual gauges on Firefly or SeeLevel display? My physical seems spot on but the virtuals are off, like 1/8-1/4 (lesser than physical).

The remote displays will be messed up from the grounding issue. The physical gauge is totally mechanical. There is a float in the tank and a linkage with a magnet on it sealed inside the tank. The physical gauge needle picks up the magnet position with it's own magnet. The variable resistance thing is attached to the physical gauge needle inside the tank gauge assembly. There are usually two wires coming out of the gauge assembly. One is grounded only to the tank body with a screw, the other connects to a wire coming from the virtual gauge electronics.

The problem is that the ground connection is trying to work thorough all the paint, rust and dirt on the tank and the tank holder, so the electronics sees an increased resistance, and reads incorrectly. Typically a better ground connection will fix this.

Another, less likely possibility is that the electronics are not calibrated to the gauge. Firefly or SeeLevel is not as subject to that issue as the old MicroPulse system. Might be worth doing a calibration check on your system, but I'd make sure the ground connection is solid first.

[rmkrum]

Originally Posted by eubank

A nice, vivid example of why fillers are not permitted to fill cylinders based on what such gauges read.

Lynn

Oh, absolute AMEN to that. That's why tanks are ALWAYS filled using weight, or the bleed screw spitting liquid to be sure. The new OPD valves made tank filling a bit safer, but I trust the bleed screw more...an overfilled tank in the desert heat around here is a largish bomb waiting to go off, IMHO. Being a front seat spectator in the middle of a potential fireball, plus flying steel shrapnel thrown in as an extra attraction is NO fun. Hopefully the pressure relief pops before the tank does...

[eubank]

NFPA 59 (the "bible" of propane) requires the OPD, but does not include it as a safe way to fill cylinders. And there's a reason for that.

Prior to OPDs, home fillers would often overfill their cylinders and wind up with dangerous conditions (and all too often enough resulting in tragic accident). The introduction of OPDs was/is the attempt to stop or at least to slow this overfilling activity.

But there's a problem. OPDs are safety devices that work when installed, but they are never again inspected for function. By contrast, using the bleed valve (if legal in that state) relies only on gravity; and using weight relies on a scale whose accuracy is checked independently by the state. In other words, there is no point in the process that relies on "equipment" that is sold initially, but never checked again.

(Of course, there's a great deal of variation in how inspections, licensing and related matters are carried out from state to state; that's because regulations governing propane handling are state based, not federal.)


Lynn

Originally Posted by rmkrum

Oh, absolute AMEN to that. That's why tanks are ALWAYS filled using weight, or the bleed screw spitting liquid to be sure. The new OPD valves made tank filling a bit safer, but I trust the bleed screw more...an overfilled tank in the desert heat around here is a largish bomb waiting to go off, IMHO. Being a front seat spectator in the middle of a potential fireball, plus flying steel shrapnel thrown in as an extra attraction is NO fun. Hopefully the pressure relief pops before the tank does...

[Schmitte]

Originally Posted by rmkrum

The propane level sensor uses a variable resistor to sense level. One end of the resistor goes to your gauge panel. The other end connects to the tank body.

The problem is the body of the tank is not grounded solidly. Tighten the heck out of the tank hold-down and see if that helps any.

If you have a multimeter, check for voltage between the body of the tank and the metal of the A-frame. There should be as close to zero as the meter can read. If not, the tank is not well grounded...

In other threads, it was suggested adding a ground wire to the screw holding the sensor to the tank, and a two-prong connector to the tank so you get a solid ground for the gauge panel through one wire, and the other wire to the panel is well connected.

Another easy test: Pull the plug on your sensor and see if the gauge reads empty. Then ground that wire to the body or A-frame of the trailer. It probably will then read full. If it does, it's for sure a grounding problem.

Let us know what you find out...

Thanks! This group is so awesome. I’ll check the ground tomorrow.

[Alex AVI]

Originally Posted by Schmitte

Thanks! This group is so awesome. I’ll check the ground tomorrow.

+1 Thank you from me too.

EUBANK - Thanks for that info on home fillers

RMKRUM - Thanks for clarifyIng which gauge is mechanical/electrical and I do see those 2 wires coming out of physical gauge. Didn't even have to go out to garage to check, I saw them on old pics I took of undercarriage area by tank gauge.

[RC-AV8R]

+2 from me . Ground check it is today...

Thanks!

[Titus]

rmkrum
Thanks for the explanation of the inside electric gauge.

One also has to keep in mind how to interpret the gauges. The 2/3 light means something less than completely full, the 1/3 light means something less than 2/3 full, and the empty light means something less than 1/3 full.

Every so often I poke my head underneath to read the tank gauge. From what I remember from a recent trip the correlation between tank gauge and electric gauge was:
full light on electric gauge = full tank gauge (where full = 80% of 18 gallons)
2/3 light on electric gauge = 3/4 on tank gauge
1/3 light on electric gauge = 1/2 on tank gauge

Fresh water tank works similarly to the above; since mentally you are counting down from full.

Black and Grey tanks are just the opposite; since mentally you are counting up from empty:
1/3 light means not completely empty
2/3 light means something more than 1/3 full
Full light means something more than 2/3 full.

[RC-AV8R]

Back from checking the tank. I couldn't get access to tighten down the tank mounting bolts (RV in storage) to check for grounding but the measurement differential was 0.4V.

One problem appeared to be the mechanical gauge - it was just hanging by its wires so using dabs of 1-minute epoxy I remounted that. Pulling in & out the sensor wires also appeared to help as the internal meter now reads 2/3 and basically matches the mechanical gauge.

Thanks again for the pointers.

[Wazbro]

Originally Posted by rmkrum

Oh, absolute AMEN to that. That's why tanks are ALWAYS filled using weight, or the bleed screw spitting liquid to be sure. The new OPD valves made tank filling a bit safer, but I trust the bleed screw more...an overfilled tank in the desert heat around here is a largish bomb waiting to go off, IMHO. Being a front seat spectator in the middle of a potential fireball, plus flying steel shrapnel thrown in as an extra attraction is NO fun. Hopefully the pressure relief pops before the tank does...

Does the built in tank on the interstates have an OPD valve?


Also how do they weigh the tank while attached to the motor home?

[Pahaska]

Originally Posted by Wazbro

Does the built in tank on the interstates have an OPD valve?

Also how do they weigh the tank while attached to the motor home?

They fill until propane comes out of the bleed valve. Fixed tanks on motorhomes are not weighed; they are filled until they start to vent liquid.

My propane level indicator is essentially inoperative. I bought the rig used with a full tank. After about 21 months, the indicator had not moved. I was on my way to see my daughter in Missouri last month and figured I should have plenty of propane in case it got cold. I stopped at a friendly dealer in Muskogee, OK and filled up. It took only $8 to fill. I was embarrassed to have bothered them.

[gmillerok1]

Originally Posted by Pahaska

They fill until propane comes out of the bleed valve. Fixed tanks on motorhomes are not weighed; they are filled until they start to vent liquid.

My propane level indicator is essentially inoperative. I bought the rig used with a full tank. After about 21 months, the indicator had not moved. I was on my way to see my daughter in Missouri last month and figured I should have plenty of propane in case it got cold. I stopped at a friendly dealer in Muskogee, OK and filled up. It took only $8 to fill. I was embarrassed to have bothered them.

You should have at least waved as you drove by! One question: Does anyone else's tank fill VERY slowly. It's like there is some obstruction. It's always been that way.

My gauge stopped working. I though it was the sensor that attaches to the tank, so I replaced it. But it turned out that there is something wrong with the mechanical magnet lever inside the tank. Can't fix that very easily.

[Titus]

Mine fills in a minute or two. Never timed it, but it did not seem slow to me. We recently had 84 gallons of propane added to a tank at home. That 84 gallons took something like 10x longer than the Interstate tank - so filling rate was similar.

[Pahaska]

Originally Posted by gmillerok1

You should have at least waved as you drove by!

We stopped for a sort break at a closed Chinese restaurant in Muskogee and looked up propane dealers on my phone. We stopped at a dealer on the east side of 69 at the north end of the city. Nice clean drive-through facility and very friendly service. We have often stopped at the RV park at the south end of the city in the past.

[John Oliver]

I find the most accurate method is to observe my gas appliances. When the stove top / oven /fridge or how water heater stop working , the tank is empty. I then switch over to second tank and take empty to the nearest propane dealer and fill up. Method has workde pretty well for lots of years !

"Judgement comes from Experience, Experience comes from bad Judgement." -- Simon Bolivar