TUD - Flashing Code 7

Trane Gas Furnace: TUD

Re: Flashing Code 7

Code 7 = Gas Valve Circuit Error

CHECKOUT:

1. Check Gas Valve

• Disconnect line voltage power to the furnace.
• Unhook the 3-wire plug at the gas valve.
• Check the resistance of the gas valve coil windings ("C" to "PM").
  • Windings Open = Bad Gas Valve
  • Windings Show Resistance ⇒ 
    • Re-attach the 3-wire plug at the gas valve.
    • Unplug the 12-Pin plug from the ignition control board.
    • Check resistance between Pins 7 (RD/I) and 8 (BL/I).
      • No Resistance = Bad Wiring between Gas Valve & Ignition Control Board.

2. Check Control Board

• Re-attach the 12-Pin plug to the Ignition Control Board.
• Re-attach the 3-Pin plug to the gas valve (if loose).
• Re-apply power to the furnace.
• Energize a call for heat.
  • Still Flashes Code 7 = Bad Control Board