Our electric power plant has numerous lube oil heaters, tanks that have strip heaters surrounding them to keep the oil at around 160 degrees. I lost a control on one. Replaced it with another one which had a shorter cap tube. (old = 10", new = 4"). Now unit will not heat up oil before sensor senses top limit. Use infrared heat gun to test temp at cap tube, (which is mounted in a small metal tube welded to outside of inner tank, right next to heating elements), and it showed around 230 degrees.
Q1: Does the length of the cap tube need to be as long as the one I took out?
Unit is Hoffman-Allen brand. I can find no info on that company. They were in Springfield, Ill. when this unit was made, and installed in our plant, circa 1940.
Q2: Anyone have any links to them?
You can email me for any more info you need to help me with this problem.