Lennox Error Code E228
High Limit Switch Open - Safety Lockout
What Does E228 Mean?
The E228 error code indicates that the high limit switch has opened, meaning your furnace has reached an unsafe temperature. The high limit switch is a critical safety device that cuts power to the burner when the furnace gets too hot, preventing potential fire hazards or equipment damage.
This error requires immediate attention and should not be ignored. The furnace will remain in lockout mode until the issue is resolved and the system is manually reset.
Common Causes of E228
A clogged air filter restricts airflow over the heat exchanger, causing the furnace to overheat. This is the #1 cause of high limit trips.
Closed registers, blocked vents, or furniture blocking return air grilles can reduce airflow and cause overheating.
A failing blower motor or capacitor may not move enough air across the heat exchanger, leading to overheating.
Dust and debris buildup on the blower wheel reduces its efficiency and airflow capacity.
Crushed, disconnected, or undersized ductwork can severely restrict airflow.
The limit switch itself may be defective and tripping prematurely, though this is less common.
Safe DIY Steps (Check These First)
- •Locate your air filter (usually at the return air grille or in the furnace)
- •If it's dirty or clogged, replace it immediately
- •Use the correct size and MERV rating for your system
- •Wait 30 minutes after replacing before restarting the furnace
- •Open all supply registers at least 80%
- •Make sure return air vents are not blocked by furniture or curtains
- •Check that no rooms are completely sealed off
- •Turn off power at the breaker for 30 seconds
- •Turn power back on and wait for the system to initialize
- •Set thermostat to heat and monitor the system
When to Call a Professional
- ✓Error returns after replacing filter and checking vents
- ✓Blower motor is not running or making unusual noises
- ✓You hear rattling or grinding sounds from the furnace
- ✓Airflow from vents is weak even with new filter
- ✓You're not comfortable performing these checks
- ✓This is a recurring problem
Need Immediate Help?
ROMA Heating & Cooling provides same-day emergency service throughout Greater Vancouver
Call Now: 778-909-5731