Manual for T4 Pro - Troubleshooting and error codes + PDF Download

Manual for T4 Pro - Troubleshooting and error codes + PDF Download

Brand: Honeywell

Category: Thermostat

Manual Type:

Language:

Uploaded: April 8, 2025, 3:37 a.m.

Manual Publish Date: 2017-02-01

Warranty Summary

No warranty information found in this manual.

System Operation Settings:

  • Press the Mode button to cycle through available system modes.
  • System modes include Auto, Heat, Cool, Em Heat (for heat pumps with auxiliary heat), and Off.
  • Auto mode selects heating or cooling as needed.
  • Heat mode controls only heating.
  • Cool mode controls only cooling.
  • Em Heat controls auxiliary heat for heat pumps.
  • Off mode turns off heating and cooling, but fan can still operate if set to On or Circulate.

Fan Operation Settings:

  • Press the Fan button to cycle through available fan modes.
  • Fan modes include Auto and On.
  • Auto mode runs fan only when heating or cooling is on.
  • On mode keeps fan always on.

Troubleshooting and error codes

System test System status
Heat 0 Heat Off
Heat 1 Heat On
Cool 0 Cool Off
Cool 1 Cool On
Fan 0 Fan Off
Fan 1 Fan On
Em. Heat 0
(TH4210U only)
Em. Heat Off
Em. Heat 1
(TH4210U only)
Em. Heat On
System test System status
Heat 0 Heat Off
Heat 1 Heat On
Cool 0 Cool Off
Cool 1 Cool On
Fan 0 Fan Off
Fan 1 Fan On
Em. Heat 0
(TH4210U only)
Em. Heat Off
Em. Heat 1
(TH4210U only)
Em. Heat On

Troubleshooting and error codes

System test System status
Heat 0 Heat Off
Heat 1 Heat On
Cool 0 Cool Off
Cool 1 Cool On
Fan 0 Fan Off
Fan 1 Fan On
Em. Heat 0
(TH4210U only)
Em. Heat Off
Em. Heat 1
(TH4210U only)
Em. Heat On
System test System status
Heat 0 Heat Off
Heat 1 Heat On
Cool 0 Cool Off
Cool 1 Cool On
Fan 0 Fan Off
Fan 1 Fan On
Em. Heat 0
(TH4210U only)
Em. Heat Off
Em. Heat 1
(TH4210U only)
Em. Heat On