York 2 red flashes: The pressure switch is closed when it should be open

Source: York manual (PDF) (opens in a new tab) ↗ · Updated

Status code2 red flashesYork
What does York 2 red flashes mean?

The pressure switch is closed when it should be open. The control checks that the contacts are open at the start of each heat cycle and will not continue ignition if they are already closed.

Call a pro: jump to when to call a pro Equipment type: furnace
How it shows: LED behind the blower-door view port on a York TG9S. Each flash is 1/3 second on and 1/3 second off, then a 2-second pause: 2 red flashes

York TG9S 2 red flashes means the pressure switch is already closed when the heat cycle starts. The control will not continue ignition. The manual names a faulty pressure switch or miswiring, and it says never to adjust a pressure switch so the furnace will run. Blocked vent and a broken hose are the 3 red flash list, not this one.

Likely causes

  • A faulty pressure switch
  • Miswiring of the pressure switch

Safe checks for 2 red flashes

  1. Write down the 2 red flashes before power is removed
  2. Techniciancheck for a faulty pressure switch or miswiring. The manual says never to adjust a pressure switch to allow furnace operation
Safety firstIf you smell gas, do not touch any electrical switch or use a phone in the building; leave immediately and call your gas supplier from outside. Turn off electrical power at the furnace switch or breaker before opening any panel, and never bypass or jumper a limit, rollout or pressure switch. Gas valve, burner, venting, wiring and control-board work should be done by a licensed HVAC technician.

Capacitors can hold a charge after the power is off. Safety terms.

When to call a pro

Call a licensed HVAC technician if 2 red flashes return. This is a switch that is closed too early, not a blocked vent.

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Furnace pressure switch: guide

In this code: A faulty pressure switch

This one is for a technician to test or replace, so we only explain it and do not link to buy it.

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1 red flashFlame was sensed when there was11 red flashesThe main limit switch has opened10 red flashesThe gas valve is energized with4 red flashesThe main limit switch has opened3 red flashesThe pressure switch contacts are open7 red flashesThe flame could not be established

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