Error Code Continuous OFF

Bryant 355MAV Error Code Continuous OFF: No Power

TL;DR
Your Bryant 355MAV furnace has no power reaching the control board. The most common fix is resetting a tripped circuit breaker or flipping the furnace power switch back on.
Disclaimer
This article is for informational purposes only and does not guarantee the accuracy or completeness of the information provided. Always turn off power and gas supply before attempting any repairs. If you smell gas, leave immediately and call your gas company. Consult a licensed HVAC technician for diagnosis and repair. Any actions taken based on this information are at your own risk.

What Does Code Continuous OFF Mean?

When the amber LED on the Bryant 355MAV control board is completely off, the board is receiving no electrical power. The control requires both 115 VAC line voltage (at L1 and L2) and 24 VAC transformer voltage (at SEC-1 and SEC-2) to operate. Without either one, the furnace is completely unresponsive to thermostat calls.

This is typically one of the easiest issues to resolve because the cause is usually outside the furnace itself. A tripped circuit breaker, a power switch that got bumped off, or a blower door that isn't fully seated are the most common culprits. The 355MAV has a door safety switch that cuts all power when the blower access panel is removed or ajar.

Less commonly, a failed transformer inside the furnace can cause this condition. If the transformer has failed, you will have 115 VAC at the board but no 24 VAC — that scenario requires a technician to diagnose and replace the component.

Common Causes

Cause Likelihood DIY?
Tripped circuit breaker or blown fuse Most common ✓ DIY fix →
Furnace power switch turned off Common ✓ DIY fix →
Blower door safety switch not engaged Common ✓ DIY fix →
Failed transformer Uncommon ✗ Call a pro →

How to Fix It: Check Power Supply to Furnace

âš  Safety First
Always turn off the furnace at the power switch or breaker and shut off the gas supply before beginning. Do not proceed if you smell gas — leave the area and call your gas company immediately.

What You'll Need

Steps

  1. Turn off power at the breaker and shut off the gas supply valve Locate your electrical panel and find the breaker labeled for the furnace. Turn it to the OFF position. Find the gas shutoff valve on the gas line leading to the furnace and turn it to the closed (perpendicular to the pipe) position. If you smell gas, leave immediately and call your gas company.
  2. Check the circuit breaker Look at the furnace breaker in your electrical panel. If it has tripped (in the middle position or toward OFF), flip it fully OFF first, then back to ON. If the breaker trips again immediately, do not reset it again — this indicates an electrical fault that needs professional diagnosis.
  3. Check the furnace power switch Find the power switch on or near the furnace — it looks like a standard light switch and is sometimes labeled. Make sure it is in the ON position. This switch is commonly bumped off accidentally, especially in tight utility closets or basements.
  4. Check the blower door safety switch The 355MAV has a safety switch that cuts power when the blower access panel is removed. Make sure the panel is fully seated and latched. Press it firmly — even a small gap can disengage the safety switch and kill power to the entire board.
  5. Restore power and gas, then verify Turn the gas supply valve back to the open position (parallel to the pipe). Turn the breaker back ON. Look through the sight glass on the blower access panel — the amber LED should now be visible.
How to Verify
Look through the sight glass on the blower access panel. If the amber LED is now continuously ON (solid), the furnace has power and is in normal standby mode. Set your thermostat to call for heat and confirm the furnace starts a heating cycle.

When to Call a Professional

Contact a licensed HVAC technician if:

Sources

  1. Bryant 355MAV Troubleshooting Manual, Service/Status Code Instructions (Page 7)