Sensors

Old-Biscuit wrote:
The standard probe is nothing more then a bolt inserted thru tank wall


There was an improved probe called Horst Probes that was a wire with protective plastic sleeve but seems they are no longer in business/available


Then there is the SeeLevel System...uses capacitance




Classic RV thru wall probes with gunk on one of the probes indicating 1/4 and 3/4 tank levels



External Capacitance Sensing

Give 'em heck Mr. Biscuit... We in the know, know that the only viable level sensors are externally mounted ones. BTW, SeeLevel makes tank sensors for a lot more stuff than just RV tanks.

While it may be that soap Which by the way is NOT used in the kitchen but may be in the shower.. Is the problem. SOAP SCUM

In the kitchen Fat

(The "Dish Soap" is actually detergent different product) and Detergent Scum

Yes the problem, And not just with the tank sensors is SCUM (I will not expand that).

The standard probe is nothing more then a bolt inserted thru tank wall


There was an improved probe called Horst Probes that was a wire with protective plastic sleeve but seems they are no longer in business/available


Then there is the SeeLevel System...uses capacitance




Classic RV thru wall probes with gunk on one of the probes indicating 1/4 and 3/4 tank levels



External Capacitance Sensing

ktmrfs wrote:
the sensors (well the cheap factory ones) activate the light when there is a lower resistance to ground. normally water provides the low resistance path. But so does soap scum, grease, food etc. The sensor circuit looks for an open circuit (infinite resistance) or a resistance in the 10's of kohms. doesn't take much scum or junk on the end of the sensor tip to meet the lower resistance threshold.

This is correct except that it doesn’t matter if the sensor (actually a simple bolt) is dirty. The path of electricity is the scum between the sensors. One brand of sensors seeks to break that path with an insulator and they have some success. Unless you can somehow remove that bathtub ring and keep it off, the gages will be unreliable. Since we all use our favorite soaps, toothpaste, shampoos and other supplies, I doubt that we can find a cleaner that works for everyone.

MrWizard wrote:
The only ones that don't scum up
Are the external ones like 'sea view' ?, That are on the outside of the tank

I have no experience with using them,

SeeLevel Mr. Wizard.. SeeLevel

I installed a pair, one on my FW tank and one on my black tank. You can get a full array, black (multiples), grey (multiples), FW (multiples) and propane (multiples) depending on the depth of your wallet and installation skills.... and they offer a system monitor similar to a Tri-metric as well.

Cloud Dancer wrote:
Don't we have the technology to expect better performance from these tank sensors? What does Newell use for sensors?
Yeah, yeah,...I know,...if I had a Newell I would get workers to go in and scrub the inside of these tanks.

I believe they use SeeLevel external tank sensors. Not cheap (which is why most builders don't use them), most builders are all about cheap.

SeeLevel sensors are external and never foul with anything, are very accurate and cost a bundle.

MrWizard wrote:
The only ones that don't scum up
Are the external ones like 'sea view' ?, That are on the outside of the tank

I have no experience with using them,

I would like to hear how will they work as too. I imagine they're not immune to corruption - as scum builds up inside the tank, it will affect the external sensor too? If they're capacitive like I think they are.

Have you see the pressure sensitive tape sealed in either a silicone or PTFE envelope? Sensor is inserted vertically into a container and outputs an analog voltage on a scale linear to the volume of liquid.

A few years ago, wasn't there an external sensor that measured the pressure in the pipe or tank to define how much volume was in the tank?
Haven't seen that one advertised in a long time.

The only ones that don't scum up
Are the external ones like 'sea view' ?, That are on the outside of the tank

I have no experience with using them,

Don't we have the technology to expect better performance from these tank sensors? What does Newell use for sensors?
Yeah, yeah,...I know,...if I had a Newell I would get workers to go in and scrub the inside of these tanks.