FieldBench
York codes

York

Slow green

Status

Normal, no heat call

Idle, powered.

Walk Slow green in Diagnose

5 plates — walk the one on the cabinet

First check

1 Confirm this is not a fault

On the York TM8T this readout (Slow green) is run status, not a lockout. Write what the display actually shows and whether W/Y/G is present at the IFC.

Expect: Idle / Ht / CF / stage+CFM words change when you apply and remove the call.

If fail: If the word never changes on a real call, the call is not reaching this IFC.

If pass: The board is alive. Diagnose the comfort complaint, not this code.

The rest of the walkthrough is Diagnose.

On the plates

  • If the house is cold, the call never reached W. Check R/W at the IFC, door switch, and the thermostat.
  • LED off is no 120/24 — not this code.
  • No W at the IFC if the house is cold.
  • W path if the house is cold.

Plates that use Slow green