A
>I haven't asked a dumb question all day so...
>
>How do these 'level' gauges sense? I glanced over my tanks this
>weekend and did not see any extra wiring or tubing or anything
>that would be used to sense levels, yet my needles bounce off
>the "Full" stops. Maybe they're just hot-wired to the switch?
>
>Lowell
>
>
Generally there is a float inside the tank that drives either a mecjanical
guage or a rheostat for an electric gauge much like the fuel gauge in a car.

The problem with the new valves is they also have a float so the valve
mounted gauges have to go, at least for the moment.

when the tanks are easy to get at just pour a cup of hot water on the tank.
the gas level is

where the tank goes from hot to cold. Under the right weather conditions
and gas flow rate a frost line will appear at the gas level
 
 

>
Rick Davis 1602
54 Safari
69 Ambassador
70 Globetrotter
Amateur Radio K8DOC
NSS 14876