Old Williams Furnace Wall Heater problems - Handyman WIRE Jan 21, 2008The above wiring "solution" leaves no safety devices in the circuit. A jumper on the thermo side of the valve bypasses any wire resistances to allow the powerpile to energize the valve: "A jumper on the 'stat side of the gas valve and the heater roared to life" but there is no safety in the unit. Williams Wall Furnace Wiring Diagram | Free Wiring Diagram Williams Wall Furnace Wiring Diagram - Collections Of Wiring Diagram for Furnace Gas Valve New Gas Furnace thermocouple. Gas Furnace thermocouple Wiring Diagram Refrence Hanging Furnace. Williams Fan Coil Unit Wiring Diagram Best Gas Furnace Wiring. Gas Furnace thermocouple Wiring Diagram Best Ge Gas Furnace Wiring.