The Stovebolt Site Forums The Shop Area The Electrical Bay 3/8" npt temp sending test & problem

When I calibrate a new sender I go with an ohmmeter test first. With sender in the heated water I write down the ohm values for a serier of temps. (cool to hot)using a known good temp. instrument for reference. Then I duplicate those ohm values with a variable resistor hooked to the gauge sender input with other side of resistor grounded to case. This allows me to add a touch of resistance in series with sender to get gauge to read exactly. A one turn pot 0-250 ohms will work in a pinch. I use a 10 turn pot salvaged from some past project just because I have it. Remember these gauges don't react to change very fast so give the gauge a half a minute or so to stablized.