3 amber flashes W2 call without W1

What the control is telling you

Two-stage boards only: the control sees a second-stage heat call with no first-stage call.

Applies to: York/JCI residential gas furnaces: York UTEC IFC furnaces, York White-Rodgers IFC furnaces

Likely causes

• Thermostat wired to W2 only
• Broken or loose W1 wire
• Thermostat configuration error

Test and repair steps

1. Check the thermostat wiring at W1 and W2 on the board.
2. Make sure the thermostat energizes W1 whenever it calls W2.
3. Repair any broken W1 conductor.

Settings for these units

• Clearance to combustibles · York TM9V
• Filter size by return location · York TM9V

Other codes on the same units

• 1 red flash Flame detected with gas valve off
• 2 red flashes Pressure switch closed when it should be open
• 3 double red flashes Second-stage pressure switch not closing
• 3 red flashes Pressure switch open when it should be closed
• 4 amber flashes Cooling call (Y) without fan call (G)
• 4 red flashes Main limit switch open
• 5 red flashes Rollout switch open / limit circuit open over 15 min
• 6 red flashes Pressure switch cycling lockout