Why doesn't the emergency heat work on my Honeywell T8635L?
If the Emergency Heat does not energize on your Honeywell Thermostat (only when used with W8635B or W8835), the Emergency Heat load at W8635 or W8835 may not be connected correctly. Check that 24 Vac is present at the E terminal. If 24 Vac is not present, all connections are good, and the thermostat is properly configured, replace W8635B or W8835.
Why isn't the 2nd stage heat or cool working on my Honeywell T8635L Thermostat?
If the 2nd stage heat or cool does not energize on your Honeywell Thermostat (only when used with W8635A), the stage configuration might not be correctly set, or the cool load at the W8635 EIM is not connected correctly. Set the Stage configuration in Installer Setup for two stages of heat and/or two stages of cool. Check that 24 Vac is present at Y2, W2 or Aux. Terminal, depending on the EIM used. If 24 Vac is not present, all connections are good and the thermostat is properly configured, replace W8635A EIM or W8835.
Why doesn't the fan turn on with electric heat on my Honeywell Thermostat?
If the fan doesn't turn on when your Honeywell Thermostat calls for electric heat, the electric heat setting may not be configured, or the fan load at the W8835 or W8635 EIM might not be correctly connected. Set Installer Setup No. 4 to 1 for electric heat. Check that 24 Vac is present at the G terminal. If 24 Vac is not present, all connections are good, and the thermostat is configured, replace the W8635 EIM or W8835.
What to do if the Honeywell T8635L calls for heat/cool but the damper doesn't open?
If your Honeywell Thermostat is calling for heat or cool, but the damper isn't opening, there could be a mismatch in zone numbers. Ensure the thermostat zone number corresponds with the correct zone number for the W8703 Damper Interface Module. Also, check that terminal 1 on the W8703 Damper Interface Module is properly connected. If the W8703 indicates the damper is closed (red LED lights), replace the W8703 Damper Interface Module.
Why does my Honeywell T8635L display not come on?
The display might not be working because the thermostat isn't getting power. Ensure the thermostat is properly mounted and latched onto the wallplate. Also, check the circuit breaker and reset it if it has tripped. Examine the fuse at the fuse box and replace it if it's blown. Finally, confirm that the system switch at the equipment is in the On position.
How to adjust temperature limits on a Honeywell T8635L?
If the temperature setting on your Honeywell Thermostat won't change, it's likely that you've reached the upper or lower temperature limits. The heating limit ranges from 40° to 90°F (4.5° to 32°C), and the cooling limit ranges from 45° to 99°F (7° to 37°C). To adjust these limits, refer to Installer Setup no. 34 and no. 35.
Why does the fan run continuously on my Honeywell Thermostat?
If the fan on your Honeywell Thermostat runs continuously, it may be set to 'On' or programmed to run continuously. Press the Fan key to switch it from 'On' to 'Auto' for the current program period. To make the fan run continuously for all periods, program the fan to 'On' for each period and day.
What does “Filter” mean on Honeywell T8635L Thermostat?
The “Filter” display along with the green LED indicates that the filter has expired. No answer.
Why is my Honeywell Thermostat flashing and no air coming from the register?
When using the thermostat in zoning applications, the thermostat must wait for all other zones to end their call for heat or cool before the fan request in this zone is honored. Wait until all other zone heat or cool cycles are complete.
Why is the red LED lit on my Honeywell T8635L Thermostat?
The red LED indicates that the heat pump has signaled the thermostat about a problem. If you have a multistage heat pump, move the System switch to the Em.Ht setting. See Heat Pump Operating Instructions or no answer.
General| Power Source | Battery or Hardwired |
|---|---|
| Programmable | Yes |
| Power Method | Battery or Hardwired |
| Mounting | Wall Mounted |
| Color | White |
| Display | Digital |
| Temperature Differential | 1°F |
| Control Type | Digital |
Details the physical keys on the thermostat cover and next to the display.
Explains the information shown on the thermostat display screen.
Details how Adaptive Intelligent Recovery™ optimizes comfort and saves energy.
Instructions for setting the heating/cooling system and fan modes.
How to select Heat, Off, Cool, or Auto system modes.
How to set the fan to Auto or On operation.
How to temporarily adjust temperature settings.
Temporarily override current schedule until next period.
How to set a permanent temperature hold.
Setting a temporary hold for a specific duration like vacation.
How to view the outdoor temperature if sensor is equipped.
How to check current temperature setpoints and modes.
How to set or reset the filter change reminder.
Indicates when temperature is overridden remotely.
How to set the current day and time on the thermostat.
How to adjust the thermostat for Daylight Saving Time.
Overview of 7-day programming and its four periods.
Details the default preprogrammed schedule for all days.
Table for planning and customizing a custom 7-day schedule.
Steps to begin programming the thermostat's schedule for a day.
Troubleshooting problems with the thermostat display not showing information.
Resolving issues where temperature settings do not change or heating/cooling fails.
Diagnosing problems with system indicators, no air from registers, or filter alerts.
Addressing 'no com' errors, zoning delays, and early heat/cool activation.
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