Ruud UGRA-07EMAES Error Code LED Off: No Power to Control Board

What Does Code LED Off Mean?

A completely dark power LED on the Ruud UGRA-07EMAES means the control board is not receiving any electrical power. Without power, the furnace cannot operate at all — no heating, no blower, no thermostat communication.

The most common cause is a tripped circuit breaker or blown fuse in your electrical panel. Furnace breakers can trip due to a momentary power surge, a storm, or other electrical events. The second most common cause is the furnace power switch being turned off. This switch is usually located on or near the furnace and looks like a regular light switch — it may have been accidentally turned off.

Less common causes include a failed low-voltage transformer (which converts line voltage to the 24V the control board needs) or a failed control board (IFC). The manual advises checking line voltage power and the low voltage transformer. If power is present at the board but the LED remains off, the control board needs replacement. These latter causes require a qualified HVAC technician.

Common Causes

How to Fix It: Check the Circuit Breaker and Power Switch

What You'll Need

• Flashlight

Steps

1. Turn off the gas supply valve as a safety precaution Before troubleshooting electrical power, locate the gas shutoff valve on the gas line leading to the furnace and turn it to the OFF position (handle perpendicular to the pipe). This ensures gas does not flow while you are working on the power issue.
2. Check the circuit breaker Go to your electrical panel (breaker box) and find the breaker labeled for the furnace or HVAC system. If it is in the tripped position (usually in the middle, between ON and OFF), flip it fully to OFF first, then back to ON. If the breaker trips again immediately, do not keep resetting it — there may be a short circuit that requires an electrician.
3. Check the furnace power switch Look for a light switch on or near the furnace — this is the furnace disconnect switch. It should be in the ON position. It may have been accidentally turned off. If there is no visible switch, look for a cord plugged into an outlet near the furnace.
4. Check the furnace door panel Many furnaces have a door safety switch that cuts power when the access panel is removed. Make sure the furnace access panel is fully seated and latched. Push firmly on the panel to ensure the door switch is engaged.
5. Turn on the gas supply and observe Once power is restored (the LED should now be lit), turn the gas supply valve to ON (handle parallel to the pipe). Set your thermostat to call for heat and monitor the furnace startup.

When to Call a Professional

Contact a licensed HVAC technician if:

• The circuit breaker trips again immediately after resetting
• The LED remains off even with the breaker on and power switch on
• The furnace access panel is seated but the LED still does not light
• You notice a burning smell near the furnace
• Multiple breakers have tripped, not just the furnace breaker

✓ Verified against manufacturer service manual — March 2026