Honeywell Error Code E350: Low Battery

How to Fix Honeywell Code E350

1. Step 1: Purchase new alkaline batteries of the correct type (usually AA or AAA).
2. Step 2: Open the battery compartment on the thermostat (usually on the side, top, or front).
3. Step 3: Remove the old batteries and install the new ones, paying attention to the correct polarity (+ and -).
4. Step 4: Close the battery compartment and verify that the E350 error code has cleared. If the code persists after replacing the batteries, contact a qualified HVAC technician.

How to Reset Honeywell Code E350

1. Remove the thermostat from its wall plate.
2. Remove the batteries and wait 30 seconds.
3. Reinsert the batteries and snap the thermostat back onto the wall plate.
4. If the error persists, perform a factory reset through the menu: Menu > Preferences > Restore Factory Defaults.

Resetting clears the code from the display but does not fix the underlying fault. If the code returns after reset, proceed to the diagnostic steps above.

What Does Honeywell Error Code E350 Mean?

The E350 error code on your Honeywell thermostat indicates that the battery voltage is low. Most Honeywell thermostats use batteries to maintain settings and, in some cases, to power the thermostat itself. When the batteries get weak, the thermostat displays this error to warn you that it's time for a replacement. If you ignore this warning, the thermostat may lose its settings, or in some cases, stop working altogether. This is especially important during heating or cooling seasons, as a non-functional thermostat can leave your home uncomfortable. Replacing the batteries is a simple maintenance task that can prevent these issues.

Common Causes

• Old batteries
• Incorrect battery type
• Loose battery connection
• High thermostat usage (backlight, smart features)

Diagnostic Steps

Replacement Parts

Related Codes on Same Models

Other codes that affect the same Honeywell model families as E350.