One of the other guys in our company asked about induced voltages on the float sensor wire.
The float sensor wire (#12 THHN) shares a conduit with some of the fountain lights. (2 circuits). In the pit where the controls are located, the sensor wires share a conduit with lighting circuits as well as pump circuits for about 12 feet of conduit.
There is an induced voltage on the sensor wires. About 20 Volts on each wire with the sensor disconnected. He thinks that the induced voltage being present in the sensor conductors along with the control voltage of 24 volts may be the cause of the sticking contacts. I'm not so sure. Welded contacts, I believe, are a result of excessive current not excessive voltage.
We may, however, test his theory by installing a sheilded cable for the sensor.
We cannot, without major alterations to the fountain, install a seprate conduit for the sensor.
What do you guys think?
Brian
