would measure at 30 ohms.
A slightly shorted solenoid will have slightly higher than expected ohms (10) Circuit Terminal 2 – Lightning resistance. Completely shorted, meltdamaged solenoid at Point EE: Exed or vaporized solenoids will elimipected resistance reading is 10 ohms. nate that solenoid’s resistance from The varnished coated (insulated) the circuit. wire present inside the solenoid easily melted from the excess heat cre(11) Circuit Terminal 1 – Non-waterated by an electrical lighting enterproof connect at Point FF: Expected ing the circuit. The melting of the resistance measurement is 30 ohms. solenoid’s insulating coating creates The use of non-waterproof connects shorts within the solenoid. The efcreates opportunity for corrosion of fects of the solenoid’s internal shorts wires and wire connections. Corrois typically to act as if the solenoid is sion will increase the resistance of not present. That is, the circuit will the circuit. In this case, the measured measure as a two valve (solenoid) resistance of this circuit would be system at 15 ohms (1/2 of the 30 higher than expected, perhaps 100 ohms resistance of a single solenoid). ohms or more. If corrosion is severe Sure enough, your multimeter read- enough, the resulting effect would be ing is 15 ohms. similar to a cut wire showing an infinite amount of resistance. This corroTo locate where the short is, you will sion effect at Point FF will be affectneed to isolate various segments of ing all circuits. the circuit and measure resistance as described earlier in this article. One (12) Circuit Terminal 2 – Non-waalternative is to assume that the issue terproof connect at Point FF: Exis a shorted solenoid, so rather than pected resistance measurement is 10 isolating the system components, you ohms. As stated in response #11, the could go to each valve and test its measured resistance reading will be solenoid. higher than expected and will be increasing the resistance for all other As a note, lightning will slightly circuits. short, completely short, melt, or vaporize the solenoid’s internal wires. (13) Circuit Terminal 1 – Nicked Page 53