HVAC Code Lookup

York Furnace: 6 Flashes

A York furnace LED pattern starting with 6 flashes matches 3 documented codes: 6 red flashes, 6 amber flashes (YP9C modulating), 6 red flashes (YP9C modulating). Watch the full pattern (short vs. long flashes) to tell them apart — all 3 are explained below.

Code 6 red flashes: While the furnace was running, the pressure switch opened four times during one call for heat

Soft lockoutShown as: Six red flashes, then a two-second pause, repeating

While the furnace was running, the pressure switch opened four times during one call for heat. The furnace locks out for one hour, then tries again on its own.

Manual wording: “6 RED FLASHES: This indicates that while the unit was operating, the pressure switch opened four times during the call for heat. Check for faulty inducer, blocked vent pipe or faulty pressure switch. The furnace will lock out for one hour and then restart.”

Documented for: TG8S, TG9S, TM9E, TM9X, TM8X, TM9T, TM8T, TM9V, TM8Y, TM9Y

Likely causes, most common first

  1. Faulty inducer (draft) motor
  2. Blocked vent pipe
  3. Faulty pressure switch

What you can safely check yourself

  • Check the outside vent and intake pipe terminations for snow, ice, leaves or nests
  • Check the condensate drain and trap for a clog
  • Replace a dirty air filter

When to call a technician

If the pipes are clear and the furnace keeps dropping out, the inducer or pressure switch is failing and needs a technician.

A York furnace throwing this code repeatedly has a reason — clearing the code without fixing the cause just hides it.

Sources

Full page for York code 6 red flashes

Code 6 amber flashes (YP9C modulating): Heat pump applications only: normal operation with a call for heat pump heating

StatusShown as: Six amber flashes, two-second pause, repeating

Heat pump applications only: normal operation with a call for heat pump heating. Not a fault.

Manual wording: “Six Amber Flashes - (Heat Pump applications only) Normal operation with call for heat pump heating.”

Documented for: YP9C, YPLC modulating furnaces paired with a heat pump

Likely causes, most common first

  1. Normal dual-fuel / heat pump heating operation

When to call a technician

No service needed.

A York furnace throwing this code repeatedly has a reason — clearing the code without fixing the cause just hides it.

Source

Full page for York code 6 amber flashes (YP9C modulating)

Code 6 red flashes (YP9C modulating): Gas valve communication error

Soft lockoutShown as: Six red flashes, two-second pause, repeating

Gas valve communication error. The modulating gas valve and the control board have lost their data link, so the furnace cannot modulate or fire.

Manual wording: “Six Red Flashes - Gas valve communication error.”

Documented for: YP9C, YPLC modulating furnaces

Likely causes, most common first

  1. Loss of communication between the control board and the modulating gas valve

What you can safely check yourself

  • Turn the furnace off at the service switch for a minute and back on once

When to call a technician

Modulating gas valve communication faults are a technician job - the valve, its harness and the board all have to be checked.

A York furnace throwing this code repeatedly has a reason — clearing the code without fixing the cause just hides it.

Source

Full page for York code 6 red flashes (YP9C modulating)

Other York codes