4 - 58 Genie Z-60/34 Part No. 75861November 2003Section 4 • Repair ProceduresREV AMANIFOLDS8-13Valve CoilsHow to Test a CoilA properly functioning coil provides anelectromotive force which operates the solenoidvalve. Critical to normal operation is continuitywithin the coil that provides this force field.Electrocution hazard. Contact withelectrically charged circuits couldresult in death or serious injury.Remove all rings, watches andother jewelry.1 Tag and disconnect the wiring from the coil tobe tested.2 Test the coil resistance.Result: The resistance should be withinspecification, plus or minus 30%.Result: If the resistance is not withinspecification, plus or minus 30%, replace thecoil.Valve coil resistance specificationsDescription SpecificationProportional solenoid valve, 12V DC 4 to 5Ω(schematic items AB, AC and AG)(before serial number 4461)Proportional solenoid valve, 12V DC 3 to 4Ω(schematic items HM, HO and HR)(after serial number 4460)How to Test a Coil DiodeGenie incorporates spike-suppressing diodes in allof its directional valve coils except proportionalvalves and coils with a metal case. Properlyfunctioning coil diodes protect the electrical circuitby suppressing voltage spikes. Voltage spikesnaturally occur within a function circuit following theinterruption of electrical current to a coil. Faultydiodes can fail to protect the electrical system,resulting in a tripped circuit breaker or componentdamage.Electrocution hazard. Contact withelectrically charged circuits couldresult in death or serious injury.Remove all rings, watches andother jewelry.1 Test the coil for resistance. See How to Test aCoil.
