Trane Package Unit: YCC

Re: Heating - Code 2 - Won't Ignite

The Trane YCC package unit uses an Ignition Control Board (IGN) with an on-board spark generator for all heating functions.

Code 2 = Ignition Failure (3 Attempts)

The control can be reset by:

• Cycling power to the unit.
• Cycling the call for "W"
• Automatic reset after 2 hours

CHECKOUT:

1. Check Ignition

• Visually inspect the burners during ignition.
  • Burners should light with little or no delay from the sparker to the flame sensor.
  • Make sure the flame sensor comes in good contact with the flame.
    • Burners ignite properly --> Step 3.  Check Flame Sensor
    • Any delay or burners not igniting = Clogged Burners/Orifice or Bad Gas Valve --> Step 2.  Check Gas Valve
  • The glow plug should de-energize once flame is established.
    • Glow plug does not de-energize = Bad Control Board

2. Check Gas Valve

• Check Inlet Pressure
• Turn off power to the furnace and close the gas safety shut-off valve.
• Hook-up a gas pressure gauge to the inlet test port of the gas valve.
• Open the gas safety shut-off and check gas pressure.
  • Should be minimum of 5" w.c. for Nat. gas and 11" w.c. for propane.
    • No pressure = Gas Shut-Off --> Check the Meter
    • Low Pressure = Bad Meter or Regulator
• Re-apply power to the furnace and activate a call for heat.
• Check for 24VAC between the two gas valve feed wires at the time of ignition.
  • No power = Bad Ignition Control or Bad Wires
• Make sure the inlet gas pressure stays above minimum when the gas valve energizes.
  • Pressure drops below minimum = Bad Meter or Regulator
• Check Manifold Pressure
• Turn off power to the furnace and close the gas safety shut-off.
• Move the gas pressure gauge to the manifold (leaving) test port on the gas valve.
  • Be sure to put the plug back in the inlet test port before proceeding!
• Open the gas safety shut-off valve and re-apply furnace power.
• Activate a call for heat and monitor the manifold gas pressure during an ignition attempt. (3-3.5" w.c. for Nat. Gas, 9-11" w.c. for LP)
  • No Pressure = Bad Gas Valve
  • Good Pressure + No Ignition = Clogged Burners/Orfice ⇒ Remove burners and clean spreaders. Also make sure that the burner orifices are not clogged.

3. Check Flame Sensor

• On the multi-meter:
  • Switch the test leads to "COM" and "mA".
  • Set the meter on DC 200ù.
  • Disconnect the wire from the flame sensor.
  • Place one meter lead on the flame sensor terminal and the other on the flame sensor wire.
  • Check the reading when the burners ignite.
    • Minimum acceptable reading = 1 MicroAmp
      • Low Reading = Dirty Flame Sensor ⇒ Clean Flame Sensor & Re-check
      • Normal Reading (2 to 6 mA) + Still Shuts-Off = Bad Ignition Control
  • MOVE SENSOR LEADS BACK TO "COM" and "V" BEFORE PROCEEDING!