thermostat says 'equipment running' but my heat or ac isn't actually coming on. what gives?

Diagnosis

When the Honeywell Home T6 Pro displays "Equipment Running," it means the thermostat's internal relays have closed and it is successfully sending 24VAC power down the signal wires (such as the Y for cooling or W for heating) to your HVAC system. The thermostat believes it has done its job; the failure is occurring downstream between the thermostat wiring and the actual mechanical components of your furnace or air conditioner. This disconnect typically happens for one of three reasons: a tripped safety switch (like a float switch in a condensate pan), a blown 3-amp or 5-amp fuse on the furnace control board, or a failed contactor/capacitor in the outdoor unit. If the T6 is showing the "running" icon but no air is moving and no noise is coming from the equipment, the electrical circuit is being interrupted after it leaves the thermostat. You can confirm this by checking if the blower fan is spinning; if the fan is on but no heat/cool is produced, the issue is likely a failed igniter or compressor capacitor.

How to Fix It

To resolve this, you must isolate whether the break is in the wiring or the equipment hardware. Follow these steps precisely:

1. Power down your HVAC system at the breaker panel to prevent shorting the control board.
2. Remove the T6 Pro faceplate from the wall plate. Locate the R (power) and W (heat) or Y (cool) wires.
3. Restore power and use a multimeter set to AC voltage to measure between the R and W/Y terminals. If you see 24V while the screen says "Equipment Running," the thermostat is functioning perfectly.
4. Go to your indoor air handler or furnace. Locate the control board. Find the terminal strip where the thermostat wires land.
5. Check for a blown automotive-style blade fuse (usually a purple 3A or tan 5A fuse). If the filament is broken, replace it with an exact match.
6. Inspect the condensate overflow tray. If there is standing water, the float switch has cut the R-wire connection to prevent a flood. Clear the drain line using a wet/dry vac from the exterior exit point.
7. If the fuse is good and the pan is dry, manually jump the R wire to the Y or W terminal on the control board using a small piece of insulated wire. If the system kicks on immediately, the issue is a break in the thermostat wiring between the wall and the furnace.

If That Didn't Work

• Check the Outdoor Contactor: If you are calling for AC and the indoor blower is running but the outdoor unit is silent, the 24V signal is likely reaching the outdoor condenser but the contactor (the heavy-duty relay) is stuck or the start capacitor has failed. Look for a bulged top on the capacitor cylinder; if it's rounded rather than flat, it must be replaced.
• Verify the Flame Sensor: For heating issues where the blower runs but no heat is produced, the flame sensor may be coated in carbon. Remove the sensor (usually one screw), clean it gently with a piece of Scotch-Brite or fine sandpaper, and reinstall.
• Test the Blower Capacitor: If you hear the furnace ignite but the air never reaches the vents, the blower motor capacitor has likely failed. This prevents the motor from reaching the torque necessary to spin the fan, even though the T6 Pro is calling for "Equipment Running."
• Inspect the Door Safety Switch: Ensure the furnace blower door is seated perfectly. The T6 Pro will send the signal, but if the door switch is slightly loose, the control board will kill all power to the equipment for safety, resulting in a "running" status on the screen with zero mechanical action.

Heads Up

• Never jump the R wire to any wire other than W, Y, or G; jumping R to C or a ground wire will instantly blow the transformer or fry the T6 Pro circuit board.
• If you replace a fuse and it blows again immediately upon powering up, you have a direct short in your wiring or a grounded compressor winding. Do not keep replacing fuses; call a technician.
• The T6 Pro is sensitive to voltage drops. If you have a "C-wire" (Common wire) connected, ensure it is seated tightly; a loose C-wire can cause the thermostat to reboot or glitch, though it usually won't cause the "running" discrepancy.
• Avoid using "wire nuts" for thermostat connections; use the push-terminals provided on the T6 Pro baseplate to ensure a vibration-proof connection.