Bryant 355MAV Error Code Continuous OFF: No Power
What Does Code Continuous OFF Mean?
When the LED on your Bryant 355MAV control board is continuously off, it means the board is not receiving electrical power. The furnace cannot operate at all in this state because the control board manages every function from ignition to the blower motor.
The most common cause is a tripped circuit breaker or blown fuse at your electrical panel. The second most likely cause is the furnace power switch being turned off. This switch is typically a standard light switch located on or near the furnace and can easily be bumped to the off position.
If both the breaker and power switch are fine, the problem may be a faulty transformer or wiring issue inside the furnace. The manual specifies checking for 155 VAC at L1 and L2, and 24 VAC at SEC-1 and SEC-2, but these measurements require specialized equipment and should be left to a professional.
Common Causes
| Cause | Likelihood | DIY? |
|---|---|---|
| Tripped circuit breaker or blown fuse | Most common | ✓ DIY fix → |
| Furnace power switch turned off | Common | ✓ DIY fix → |
| Faulty transformer or wiring | Uncommon | ✗ Call a pro → |
How to Fix It: Check the Circuit Breaker and Power Switch
What You'll Need
Steps
- Turn off power and gas supply as a precaution Before investigating, turn the gas shutoff valve near the furnace to the OFF position (perpendicular to the pipe). If you smell gas at any point, leave immediately and call your gas company.
- Check the circuit breaker Go to your home's main electrical panel and find the breaker labeled for the furnace or HVAC system. If it is in the middle (tripped) position, flip it fully to OFF first, then back to ON. Some panels have fuses instead of breakers — check if the furnace fuse is blown and replace it with one of the same amperage.
- Check the furnace power switch Look for a standard light switch on or near the furnace, usually on the side of the unit or on a nearby wall. Make sure it is in the ON position. This switch is easily mistaken for a regular room light switch and may have been turned off accidentally.
- Restore gas and verify power Turn the gas supply valve back to ON (parallel to the pipe). Check the furnace control board through the access panel — the LED should now be lit. Set your thermostat to call for heat and confirm the furnace starts.
When to Call a Professional
Contact a licensed HVAC technician if:
- The circuit breaker trips again immediately after resetting
- The power switch is on and the breaker is not tripped, but the LED remains off
- You notice a burning smell or signs of electrical damage near the furnace
- You are not comfortable working around your electrical panel
✓ Verified against manufacturer service manual — March 2026