Amana AMVM970803BN Error Code EE3: Primary Limit Circuit Open

What Does Code EE3 Mean?

Error code EE3 on the Amana AMVM970803BN indicates that the primary limit circuit is open. The high-limit safety switch has detected that temperatures inside the furnace have exceeded safe levels, and it has opened the circuit to shut down the gas burners. The circulator blower continues to run to cool down the heat exchanger.

The high-limit switch is a critical safety device that prevents the heat exchanger from overheating, which could cause cracking or other damage. When airflow across the heat exchanger is insufficient, heat builds up inside the furnace instead of being distributed through the ductwork. The limit switch trips to prevent this dangerous condition.

The most common cause is a dirty or clogged air filter that restricts airflow through the system. Blocked or closed supply registers and return grilles can also reduce airflow enough to trigger the limit switch. A failing blower motor that runs at reduced speed, blocked ductwork, or a loose wire in the limit circuit are less common but possible causes.

Common Causes

How to Fix It: Replace the Air Filter and Restore Airflow

What You'll Need

• Replacement air filter (correct size for your system) 🛒 Find at FiltersFast · 🛒 Find at Amazon
• Flashlight

Steps

1. Turn off power at the breaker or furnace switch and shut off the gas supply valve Locate the furnace circuit breaker and flip it to OFF, or turn off the furnace power switch. Turn the gas shutoff valve to the OFF position (perpendicular to the pipe). If you smell gas, leave immediately and call your gas company.
2. Check and replace the air filter Remove the air filter from the return air duct or furnace filter slot. An overheating furnace almost always has a dirty filter — if the filter is visibly dirty, gray, or clogged, replace it immediately with a new filter of the correct size. Make sure the airflow direction arrow on the new filter points toward the furnace.
3. Verify all supply and return vents are fully open Walk through every room and ensure all supply registers and return grilles are fully open and not blocked by furniture, curtains, or rugs. The furnace needs unrestricted airflow to prevent overheating. Open any vents that have been closed.
4. Allow the furnace to cool down After replacing the filter and opening vents, wait 5-10 minutes with the power off to let the furnace cool down. The high-limit switch is a self-resetting device on this furnace — it will automatically close once the temperature drops to a safe level.
5. Restore power and gas, then test Turn the gas supply valve to ON (parallel to the pipe). Restore electrical power. Set your thermostat to call for heat. The furnace should start normally now that the limit switch has reset. Monitor through a complete heating cycle to confirm the burners stay on and the blower delivers warm air.

When to Call a Professional

Contact a licensed HVAC technician if:

• EE3 returns after replacing the filter and opening all vents
• The blower motor is not running at full speed or makes unusual noises
• The furnace overheats repeatedly even with a clean filter
• You notice hot air coming from the furnace cabinet or unusual heat near the unit
• The limit switch does not reset after the furnace has cooled down

✓ Verified against manufacturer service manual — March 2026