YP9C - Flashing Code 11

York Gas Furnace: YP9C

Re: Flashing Code 11

This indicates that a primary limit switch has opened and has remained open for more than five minutes. This condition is usually associated with an air circulation failure. 

► Code 11 is a Hard-Lockout which requires cycling 24VAC power to the furnace board to reset (or cycling 115V power).

CHECKOUT:

1. Check Blower Motor/Wheel

• Turn off power to the furnace.
• Open the blower access door and check the condition of the blower wheel.
• Check to see if the motor and wheel turn freely.

2. Check Motor Operation

• Turn on power to the furnace.
• Energize a call for "Fan" by jumping "R" to "G".
  • Blower motor does not start → Step 3. Check Control Board/Motor
  • Blower motor starts & runs normally → Step 4. Check Limits
  • Motor starts but makes terrible noise ⇒ Blower Wheel Problem

3. Check Control Board/Motor

• At the blower motor power plug, check for 120VAC between "Blk" and "Wht".
  • No Power = Broken/Loose Wiring or Bad Power Factor Choke
  • Power Present + No Blower = Bad Motor or Bad Control Board (Most Likely the Motor)

4. Check Limits

• Check for 24VAC between sides of the primary limit and "C".
  • Power on Both Sides = Limit Closed
  • Power on One Side Only = Limit Open 
    • Limit Open + Cool Chamber = Bad Limit
• Alternatively, check for 24VAC between the Red/Grn wire on Pin#3 and the Red/Grn wire on Pin#6 of the 6-pin plug.
  • No Power = Limit Closed
  • Power Present = Limit Open