Bryant 315AAV Error Code Continuous OFF: No Power

What Does Code Continuous OFF Mean?

On the Bryant 315AAV, the amber status LED behind the sight glass in the blower access door is your window into the control. When that LED is completely dark, the Variable Speed Furnace Control is not powered at all — it is not merely idle, it has no line or low voltage to run on. The control requires 115VAC at its L1 and L2 terminals and 24VAC at SEC-1 and SEC-2 to operate; if either is missing, the board goes dark and cannot flash any 2-digit status code.

Because this is a variable-speed, induced-combustion furnace, a dark board also means the ECM blower and the inducer motor receive no signal, so nothing moves when the thermostat calls for heat. This is different from a steady-ON LED (the normal standby indication) and different from status code 24, where a short circuit has specifically blown the 3-amp secondary fuse on the board while line power is still present. A continuously OFF LED points further upstream — to the building breaker, the furnace disconnect switch, the blower-door safety interlock, or the transformer.

Bryant makes this the one condition a homeowner can safely begin troubleshooting, because the two most likely causes — a tripped breaker and a furnace switch left off — are simple to check. If line power is confirmed but the board stays dark, the problem is usually a failed transformer or wiring, which is a technician's job.

What You'll Notice

• No amber light at all in the sight glass on the blower access door
• The furnace does nothing when the thermostat calls for heat — no inducer, no blower, no ignition
• A wall thermostat powered from the furnace may go blank or lose its display
• The breaker labeled for the furnace may sit in the middle 'tripped' position, or the switch on/near the furnace is OFF

Common Causes

How This Is Diagnosed

Diagnosis works from the power source inward: confirm the furnace breaker is on, then the furnace disconnect switch, then that the blower access door is closed enough to engage its safety interlock. If all of those are good and the board is still dark, a technician measures for 115VAC at L1/L2; if line voltage is present but there is no 24VAC at SEC-1/SEC-2, the transformer or its low-voltage wiring is the suspect.

How to Fix It: Restore Power: Check the Breaker, Switch, and Blower Door

What You'll Need

• Flashlight

Steps

1. Turn off electrical power at the breaker or furnace switch and shut off the gas supply Before inspecting anything, set the furnace disconnect switch (or its breaker) to OFF and turn the manual gas shutoff valve perpendicular to the pipe. If you smell gas at any point, leave the house immediately and call your gas company.
2. Check and reset the circuit breaker At the electrical panel, find the breaker for the furnace. If it sits in the middle 'tripped' position, push it fully OFF and then back ON. A breaker that trips again immediately signals a short circuit — stop and call a technician.
3. Confirm the furnace power switch is on There is a switch that looks like a light switch on or near the furnace, often mistaken for a light and bumped off during storage or cleaning. Make sure it is ON.
4. Reseat the blower access door The blower door presses a safety interlock switch that cuts power when the door is open. Make sure the door is fully seated and latched so the interlock is engaged.
5. Restore power and watch the LED Turn the gas back ON (handle parallel to the pipe), restore power, and look at the sight glass. A steady amber LED means power is restored and the control is back in normal standby.

When to Call a Professional

Contact a licensed HVAC technician if:

• The breaker trips again immediately after you reset it
• The board stays dark even with the breaker on, the switch on, and the door closed
• You confirm 115V power is reaching the furnace but the LED never lights
• There is a burning smell or scorching near the control board or transformer

✓ Verified against manufacturer service manual — March 2026