York furnace 1 amber flash: Normal operation with a call for heat, Emerson boards

One amber flash means the furnace is running normally on a call for heat, and on a two stage model that the first stage is on. It is a status indication, not a fault.

Applies to: York, Luxaire and Coleman gas furnaces using the last-generation White-Rodgers Emerson integrated furnace controls — part numbers 265901, 265902, 265903, 265904, S1-33109167000, S1-33109168000 and S1-33109169000 — as documented in technical service letter ST-045-09.

What it means

This is the White-Rodgers Emerson generation's way of showing an active heat call. It is worth its own page because the newer UTEC boards do not use it — on those, a call for heat shows as a steady amber heartbeat instead, and one amber flash is not part of their vocabulary. So the same furnace brand indicates the same normal condition two different ways depending on which board is fitted, and someone counting a single amber flash against the wrong table will find nothing and assume something is wrong. On a two stage furnace this specifically means first stage is running; two amber flashes means second stage.

Most common causes

• The thermostat is calling for heat, which is the normal reason.
• On a two stage furnace, first stage heat is running.
• The board fitted is a last-generation White-Rodgers Emerson control rather than a UTEC one.

How to diagnose it

1. Confirm the flash is amber rather than red. Red is the fault colour on both generations.
2. Check the board part number if the indication does not match what you expected — the two generations differ here specifically.
3. Note whether the house is heating. If it is, there is nothing to diagnose.
4. Two amber flashes means second stage heat and is equally normal.

How to fix it

1. Nothing. This is the furnace reporting normal operation.
2. If the furnace is not producing heat while showing this, the problem is not in the code — have the equipment looked at.

Notes

Amber on these boards is used entirely for status and for wiring observations such as a second stage call with no first stage. Every genuine fault is red.

Related

• Which York control board you have — York used two control board generations with different code meanings
• 2 amber flashes — Normal operation with a call for second stage heat

All codes for this manufacturer

York, Luxaire and Coleman furnace flash codes — every code, with what differs between models.

Sources

• Johnson Controls Unitary Products technical service letter ST-045-09 — York UTEC furnace boards, fault code tables and retrieval procedure