Nest Thermostat Error E5: Why Is No Heating Detected and How Do I Fix It?
- Furnace igniter failure
- Gas valve not opening
- Dirty flame sensor
Problem Description
Nest error E5 means the thermostat called for heat but did not detect any temperature rise. The heating system may have failed to ignite or is not producing enough heat.
Symptoms
- Nest shows E5 error
- No heating detected message
- Furnace running but no heat
- Temperature not rising
- System cycling on and off
- E5 appears after 30 minutes
Recognize these? Here's what usually causes it.
Common Causes
- Furnace igniter failure
- Gas valve not opening
- Dirty flame sensor
- Blocked air filter
- Heat exchanger problem
- Thermostat placement issue
Most fixes happen in the first 3 steps.
If E5 persists with a working furnace, the issue may be Nest placement detecting heat from nearby sources giving false readings.
Tools & Requirements
These tools will help you complete this fix.
Replacement filter
Levoit Vital 100 Air Purifier Genuine Replacement Fi...
Steel wool
Steel Wool Grade 0000 - Finest Grade - 16 Steel Wool...
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Step-by-Step Solution
Check Furnace Operation
Go to furnace when heat is called. Listen for ignition sequence - you should hear clicks and see flame. If no ignition, furnace has internal issue needing HVAC service.
Replace Air Filter
A clogged filter restricts airflow and can cause overheating shutoff. Replace filter if dirty. This is the most common cause of E5 errors.
Needed for this step
Levoit Vital 100 Air Purifier Genuine Replaceme...
$54.99Clean Flame Sensor
Turn off furnace power. Locate flame sensor rod in burner area. Remove and clean with fine steel wool or emery cloth. Dirty sensor causes ignition failures.
Needed for this step
Steel Wool Grade 0000 - Finest Grade - 16 Steel...
$11.95Check Furnace Error Codes
Most furnaces have LED error codes on the control board. Check for flashing patterns and compare to manual. This identifies specific furnace issues.
Verify Thermostat Placement
If Nest is in direct sunlight or near heat source, it may not accurately sense room temperature. Move thermostat to interior wall away from vents and windows.
Quick Solutions
Still having issues? This is usually the deeper cause below.
If the sensor still misses events after repositioning, check whether a scheduled 'home' or 'away' mode is overriding the sensitivity setting silently.
E5 often appears in very cold weather when heating demand exceeds system capacity. This is normal for undersized systems.
Thermostat issues that keep returning are often caused by stale backup-battery memory holding old settings across power cycles without the user realising.
- Furnace igniter failure
- Gas valve not opening
- Dirty flame sensor
- Blocked air filter
- Heat exchanger problem
Before you go — try one of these (they fix most cases).
Most popular upgrades chosen by Google Nest Thermostat owners.
Google Nest Thermostat Trim Kit - Made for the Nest Therm...
Google Nest Thermostat Trim Kit - Made for the Nest Therm...
Google Nest Thermostat - Smart Thermostat for Home - Prog...
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Official Manufacturer Manual
Google Nest provides official product documentation through their online manual rather than downloadable PDF. Access setup guides, troubleshooting steps, and product specifications for your Google Nest Thermostat.
Source: google.com
Need More Help? Google Nest Support
Note: The contact information below connects you directly to Google Nest's official customer support team, not Trunetto. They can help with warranty claims, device replacements, and advanced technical issues.
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