York furnace Amber heartbeat: Normal operation with a call for heat

An amber heartbeat means a call for heat is present and the furnace is responding. On two-stage models it specifically indicates first stage operation.

Applies to: York, Luxaire and Coleman gas furnaces using the UTEC integrated furnace control boards documented in technical service letter ST-045-09. On two-stage models this indicates first stage.

What it means

Amber on these boards indicates heating. A heartbeat in amber means the thermostat has asked for heat and the control is acting on it, and on a two-stage furnace that means first stage — the lower firing rate where a two-stage furnace spends most of its running time. This is useful during troubleshooting because it confirms the call arrived: an amber heartbeat with no heat means the furnace is trying and something in the sequence is not completing, which is a different investigation from a furnace that was never asked to run.

Most common causes

• The thermostat is calling for heat and the furnace is responding. This is normal.
• A two-stage furnace running on first stage, which is expected in mild to moderate conditions.
• The furnace working through its start sequence — inducer prepurge, ignition, or blower on-delay.

How to diagnose it

1. Note how long the amber heartbeat continues without heat reaching the house. A normal sequence takes well under a minute from call to burners.
2. Listen for the inducer starting, which confirms the sequence has begun.
3. On a two-stage furnace, note whether it ever steps up to second stage in cold weather. A furnace stuck on first stage may have a second-stage fault.
4. If the house is not warming while this shows, check the air filter and registers before assuming a furnace fault.

How to fix it

1. Nothing to fix if the furnace goes on to heat normally.
2. If the amber heartbeat persists with no heat, have the stored fault codes replayed — the sequence is stalling and the history will say where.
3. If the furnace never reaches second stage in cold weather, that is worth investigating.
4. Do not clear the fault memory while troubleshooting.

Notes

Two-stage furnaces are designed to run on low fire most of the time. An amber heartbeat for long periods in mild weather is the furnace behaving exactly as intended rather than struggling.

Related

• Green heartbeat — Normal — no call for heat
• 3 double red flashes — Second stage pressure switch stuck open

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