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Ecobee Not Turning Off Heat: Complete Troubleshooting Guide

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Is your Ecobee stuck running the heat continuously? The house is getting too hot, but the furnace won’t stop even though the temperature is well above your setpoint. This comprehensive guide walks you through diagnosing and fixing the issue, from thermostat configuration problems to stuck relays and short circuits.

Table of Contents

๐Ÿ” Quick Diagnosis: Why Won’t Heat Turn Off?

When heat won’t turn off, you’ll typically see one of these scenarios:

SymptomMost Likely CauseFix Difficulty
Heat runs constantly, Ecobee shows correct temp reachedThermostat stuck calling for heat (software/hardware)Easy-Medium
Heat runs constantly, Ecobee screen blank or frozenPower/wiring issue or failed thermostatEasy-Medium
Heat cycles off briefly then immediately back onSetpoint too close to current temp or differential too tightEasy
Only happens with certain hold/schedule settingsSchedule or comfort setting misconfiguredEasy
Furnace runs even when Ecobee is removed from wallShort circuit in wiring or stuck relay at furnaceMedium-Hard
Started after thermostat installation/wiring changeMiswiring or incorrect terminal connectionsEasy-Medium

๐Ÿšจ IMMEDIATE SAFETY STEPS

If your home is overheating dangerously (above 85ยฐF):

  1. Turn off furnace immediately:
    • Locate furnace power switch (usually on or near furnace – looks like light switch)
    • Flip to OFF position
    • OR flip breaker labeled “Furnace” or “HVAC” at main panel
  2. Cool down your home:
    • Open windows
    • Turn on ceiling fans
    • Close heating vents in overheated rooms
  3. After cooling – troubleshoot the issue below
  4. If you smell gas or see smoke – evacuate and call 911

โšก Problem #1: Ecobee Software Glitch or Frozen Screen

This is a common cause – about 30% of “won’t turn off” cases.

What’s happening:

The Ecobee’s software has crashed, frozen, or is stuck in a heating call. The screen may show normal or may be frozen/unresponsive. The thermostat is continuously sending the heat signal (24VAC on W terminal) even though it shouldn’t.

How to diagnose:

  • Temperature shown on Ecobee is at or above setpoint
  • Screen shows “Heating” even though temp is reached
  • Touch screen is unresponsive or sluggish
  • Thermostat recently received software update or experienced power glitch

Solution:

Solution 1A: Force a reboot (soft reset)

  1. Remove thermostat from wall plate – pull straight off (wires stay connected to plate)
  2. Wait 30 seconds – this drains capacitors and forces full shutdown
  3. During this time, furnace should turn off (no 24VAC on W terminal)
  4. Reattach thermostat to wall plate – press firmly until it clicks
  5. Wait for boot sequence (1-3 minutes)
  6. Check if heating control works properly now
  7. Raise and lower temperature to test on/off cycling

Success rate: 70% – this fixes most software glitches

Solution 1B: Factory reset (if reboot doesn’t work)

โš ๏ธ Warning: Erases all settings, schedules, sensor pairings

  1. From home screen, tap Menu
  2. Go to Settings โ†’ Reset โ†’ Reset All Settings
  3. Confirm reset
  4. Thermostat reboots and starts setup wizard
  5. Reconfigure equipment settings (see Problem #4)
  6. Recreate your schedule
  7. Re-pair remote sensors

Solution 1C: Check for firmware issues

  1. Menu โ†’ About โ†’ Version
  2. Check current firmware version
  3. If recent update: Google “Ecobee [version number] heating issues” to see if known bug
  4. Contact Ecobee support if firmware issue suspected: 1-877-932-6233
  5. They may push firmware rollback or fixed version

๐Ÿ”Œ Problem #2: Stuck or Shorted W Wire

This is the #1 hardware cause – about 40% of cases.

What’s happening:

The W (heat) wire is either:

  • Shorted to R wire somewhere (constant 24VAC on W terminal)
  • Stuck closed inside thermostat (relay welded shut)
  • Damaged insulation causing intermittent shorts
  • Pinched or stapled through, touching metal

When W and R are shorted together, the furnace sees constant “call for heat” signal regardless of what the Ecobee is trying to do.

How to diagnose:

  • Heat runs even when Ecobee is set to OFF mode or Cool mode
  • Heat continues running even after removing Ecobee from wall plate
  • Recent work done on walls (nails, screws, drilling)
  • Wire routing goes through areas that may have been disturbed

Solution:

Test 1: Remove Ecobee and check if heat stops

  1. Set Ecobee to OFF mode
  2. Remove thermostat from wall plate (wires stay connected to plate)
  3. Observe furnace for 2-3 minutes
  4. If heat STOPS: Problem is in the Ecobee unit itself (see Problem #3)
  5. If heat CONTINUES: Problem is in wiring or furnace (continue below)

Test 2: Check for wire short at thermostat

  1. Turn off power at furnace breaker
  2. At the wall plate, remove W wire from terminal (note which terminal it came from)
  3. Separate W wire from all other wires – don’t let it touch anything
  4. Turn power back on
  5. Wait 2-3 minutes
  6. If heat STOPS: W wire was shorted to another wire at the thermostat – check wire bundle
  7. If heat CONTINUES: Short is somewhere else in the wire run or at furnace

Test 3: Inspect wire bundle behind wall plate

  1. Turn off power at breaker
  2. Remove wall plate from wall (unscrew)
  3. Gently pull wire bundle out
  4. Inspect for:
    • Damaged insulation – bare copper exposed
    • Wires touching each other – especially W and R
    • Pinch marks from staples or drywall anchors
    • Wire strands from one wire touching another wire’s terminal
  5. If damage found:
    • Cut back to good wire (may need to run new wire if too short)
    • Re-strip fresh insulation
    • Ensure wires don’t touch when reconnected
  6. If no damage visible but still suspect short – test continuity (see below)

Test 4: Continuity test for wire shorts

You’ll need a multimeter:

  1. Turn off power at breaker
  2. At thermostat, disconnect all wires from wall plate
  3. At furnace, disconnect all wires from control board
  4. Set multimeter to continuity/resistance mode (ฮฉ)
  5. Test W wire to every other wire:
    • Touch one probe to W wire at thermostat end
    • Touch other probe to R wire at thermostat end
    • Should read infinite resistance (no continuity – “OL” on meter)
    • Repeat for W to G, W to Y, W to C
  6. If you get continuity (beep or low resistance): Wires are shorted together somewhere in the wall
  7. Finding the short location:
    • Check inside wall near thermostat (most common)
    • Check attic/crawlspace where wire runs
    • Look for staples driven through wire
    • Check junction boxes
  8. If short cannot be located: Run new thermostat wire (18/5 or 18/8 wire, $20-40)

๐ŸŽ›๏ธ Problem #3: Failed Ecobee Relay (Hardware Failure)

What’s happening:

Inside the Ecobee is a small relay that switches the W terminal on and off. If this relay fails in the closed position (welded contacts), it continuously sends 24VAC to the W wire regardless of software commands.

How to diagnose:

  • Heat runs continuously
  • Removing Ecobee from wall plate stops the heat immediately
  • All wiring tests show no shorts
  • Ecobee screen and software work normally
  • Often happens on older Ecobee units (3+ years)

Solution:

Verify relay failure:

  1. Set Ecobee to OFF mode – heat should stop
  2. If heat continues, wait 2 minutes (may be compressor protection delay)
  3. Remove Ecobee from wall plate
  4. If heat immediately stops – confirms internal relay failure

Temporary workaround:

While waiting for replacement:

  1. Leave Ecobee on wall plate
  2. Use manual temperature adjustment to control heating
  3. Set slightly lower temperature than desired
  4. Monitor closely – don’t leave home unattended
  5. Consider disconnecting W wire at furnace if unsafe

Permanent solution – warranty replacement:

  1. Call Ecobee support: 1-877-932-6233
  2. Explain the relay failure symptoms
  3. Provide purchase date and serial number (on back of thermostat)
  4. Ecobee has excellent warranty coverage:
    • 3 years for most models (Ecobee3 Lite, Ecobee4, SmartThermostat)
    • Often replace free even slightly out of warranty
  5. They’ll send replacement unit (usually 3-5 days)
  6. Install replacement and configure

Cost if out of warranty: $100-250 for new Ecobee vs repairing (repair not economical)

๐Ÿ”ง Problem #4: Incorrect Equipment Configuration

What’s happening:

The Ecobee doesn’t know what type of heating system you have, so it’s controlling it incorrectly. Common issues include heat pump configured as conventional furnace, or wrong number of stages configured.

How to diagnose:

  • Recently installed Ecobee or did factory reset
  • Heat behavior seems erratic – sometimes turns off, sometimes doesn’t
  • Configuration screens show equipment you don’t actually have
  • Heat runs longer than expected before cycling off

Solution:

Verify equipment configuration:

  1. From home screen, tap Menu
  2. Go to Settings โ†’ Installation Settings โ†’ Equipment
  3. Review what’s configured – does it match your actual system?

Common mistakes:

Your Actual SystemWrong Config CausesCorrect Config
Gas/Oil/Electric furnaceConfigured as heat pumpHeating: Conventional, stages as needed
Single-stage furnaceConfigured as 2-stageHeating: 1 stage only
Heat pump with aux heatAux configured as primaryHeating: Heat pump, with aux backup
Electric baseboardConfigured as forced airMay need line voltage thermostat instead

Reconfigure equipment correctly:

  1. Menu โ†’ Settings โ†’ Installation Settings โ†’ Equipment
  2. Tap Reconfigure Equipment
  3. For gas/oil/propane/electric furnace:
    • Select Conventional
    • Number of heat stages: 1 (most common) or 2 (two-stage furnaces)
    • Reversing valve: OFF (not a heat pump)
  4. For heat pump:
    • Select Heat Pump
    • Reversing valve: O or B (check equipment label)
    • Aux heat stages: Configure if you have backup heat
  5. Verify wiring detection:
    • Ecobee shows which wires are detected at each terminal
    • W1 should show “Connected” (white wire for heat)
    • If shows “Not detected” – wire connection problem
  6. Complete configuration and test

Check compressor/furnace protection settings:

  1. Menu โ†’ Settings โ†’ Installation Settings โ†’ Thresholds
  2. Compressor to Compressor: Default 5 minutes – prevents short cycling
  3. Compressor to Furnace / Furnace to Compressor: Default 5 minutes
  4. If set too low (under 3 minutes), may cause heating to restart too quickly
  5. Recommended: Keep at 5 minutes unless manufacturer specifies otherwise

๐ŸŒก๏ธ Problem #5: Temperature Differential Set Too Tight

What’s happening:

The temperature differential (how far temperature must drop before heat turns off and how far before it turns back on) is set too narrow. Heat turns off for 30 seconds then immediately back on, making it seem like it never stops.

How to diagnose:

  • Heat cycles off briefly (you hear furnace stop)
  • Then immediately turns back on (within 1-2 minutes)
  • Temperature oscillates within 0.5ยฐF of setpoint
  • Happens more when outdoor temperature is mild

Solution:

Adjust heat differential settings:

  1. Menu โ†’ Settings โ†’ Installation Settings โ†’ Thresholds
  2. Heat Differential:
    • This is the “undershoot” – how far below setpoint before heat turns ON
    • Default: 0.5ยฐF
    • Try increasing to 1.0ยฐF – gives more buffer
  3. Cool Differential:
    • Affects cooling, but if too tight can cause conflicts in Auto mode
    • Default: 0.5ยฐF
    • Keep 0.5-1.0ยฐF
  4. Minimum time between stages:
    • Ensures furnace doesn’t short-cycle
    • Should be 5-10 minutes minimum
  5. Save and test for several heating cycles

Understanding how differential works:

  • Setpoint: 70ยฐF
  • Heat differential: 1.0ยฐF
  • Heat turns ON when: Temperature drops to 69ยฐF (70 – 1.0)
  • Heat turns OFF when: Temperature reaches 70ยฐF
  • With tight differential (0.3ยฐF), heat cycles too frequently

Recommended settings for most systems:

  • Gas/Oil furnace: 0.5-1.0ยฐF differential
  • Electric resistance: 0.5-1.5ยฐF differential
  • Heat pump: 1.0-2.0ยฐF differential (slower heating)

๐Ÿ“… Problem #6: Schedule or Comfort Setting Issues

What’s happening:

Your schedule, hold, or smart features are overriding normal temperature control and keeping the setpoint artificially high.

How to diagnose:

  • Home screen shows “Hold” or schedule name (Home, Away, Sleep)
  • Temperature setpoint seems higher than you set
  • Heat won’t turn off even though current temp = displayed setpoint
  • Smart Home/Away or Smart Recovery is enabled

Solution:

Check for active holds:

  1. Look at home screen
  2. If you see “Hold until…” banner at top
  3. Tap the hold banner
  4. Select Remove Hold or Resume Schedule
  5. Verify heat turns off when temp reached

Check current schedule setpoint:

  1. Your schedule may have a comfort setting at a higher temp than you think
  2. Tap the schedule name on home screen (e.g., “Home”, “Away”, “Sleep”)
  3. View what temperature that comfort setting is actually set to
  4. If too high: Menu โ†’ Schedule and edit that comfort period

Disable Smart Home/Away (if causing issues):

  1. Menu โ†’ Settings โ†’ Preferences โ†’ Smart Home/Away
  2. Toggle to OFF
  3. This feature auto-adjusts to Away when you leave
  4. Can cause unexpected temperature changes
  5. Test with it off to see if behavior improves

Disable Smart Recovery:

  1. Menu โ†’ Settings โ†’ Preferences โ†’ Smart Recovery
  2. Toggle to OFF
  3. Smart Recovery starts heating early to reach setpoint by scheduled time
  4. Can make it seem like heat won’t turn off
  5. Disable if you prefer precise schedule timing

Check “Away” temperature settings:

  1. Menu โ†’ Comfort Settings โ†’ Away
  2. If Away heat setpoint is high (e.g., 68ยฐF)
  3. And you’re frequently in Away mode
  4. Heat will maintain that temperature
  5. Lower Away heat setpoint to 60-65ยฐF for energy savings

๐Ÿ  Problem #7: Furnace Relay Stuck Closed

What’s happening:

The relay on your furnace control board that responds to the W signal has failed in the closed position. Even when the Ecobee stops sending 24VAC on W wire, the furnace relay stays closed and keeps calling for heat.

How to diagnose:

  • Heat runs continuously
  • Ecobee shows heat is OFF (not calling for heat)
  • Disconnecting W wire at thermostat doesn’t stop heat
  • Furnace continues running even with W wire removed at furnace control board
  • Usually happens on older furnaces (10+ years)

Solution:

Test for stuck relay at furnace:

  1. Turn off power at breaker
  2. At furnace control board, disconnect W wire from W terminal
  3. Turn power back on
  4. Wait 2-3 minutes
  5. If heat STOPS: W wire had short to R somewhere (see Problem #2)
  6. If heat CONTINUES: Relay on control board is stuck closed – control board failure

Temporary emergency shutoff:

Until you can get repair:

  1. Turn off furnace power switch
  2. OR disconnect W wire at furnace and cap it (electrical tape)
  3. This prevents runaway heating
  4. Turn on only when you need heat, monitor closely

Permanent solution – control board replacement:

This requires HVAC technician unless you’re experienced:

  1. Diagnose the exact failure:
    • Failed relay (most common)
    • Failed control board
    • Shorted wire at board connection
  2. Control board replacement:
    • Part cost: $100-300 depending on furnace model
    • Labor: $150-300
    • Total: $250-600
  3. DIY replacement (if comfortable):
    • Turn off all power (breaker AND gas if applicable)
    • Take photo of all wire connections before removing
    • Order exact replacement board (furnace model + part number)
    • Match all connections exactly
    • Many boards have wire labels molded into plastic
  4. Some boards have replaceable relays:
    • If you’re handy with electronics
    • Identify relay part number (printed on relay)
    • Order replacement relay ($5-15)
    • Desolder old relay, solder new one
    • Much cheaper than full board replacement

๐Ÿ”ฅ Problem #8: Heat Anticipator or Cycle Rate Settings (Older Ecobee Models)

What’s happening:

Some Ecobee models have cycle rate settings that determine how aggressively the thermostat controls temperature. Wrong setting can cause heat to stay on longer than expected.

How to diagnose:

  • Older Ecobee model (Ecobee3, Ecobee3 Lite, Ecobee4)
  • Heat seems to “overshoot” target temperature by 2-3ยฐF
  • More pronounced in mild weather
  • Configuration was recently changed

Solution:

Check cycle rate settings:

  1. Menu โ†’ Settings โ†’ Installation Settings โ†’ Thresholds
  2. Look for Heat Cycle Rate or similar setting
  3. Options typically:
    • Slow (1-2 cycles/hour): For high-mass systems (radiant, boiler)
    • Medium (3 cycles/hour): For standard furnaces (most common)
    • Fast (5-6 cycles/hour): For electric baseboards, low-mass systems
  4. For gas/oil furnace: Use Medium setting
  5. For electric furnace: Use Medium or Fast
  6. For heat pump: Use Slow or Medium

Wrong cycle rate causes:

  • Too fast: Short cycling, wear on equipment
  • Too slow: Temperature overshoot, heat stays on too long

๐Ÿงช Advanced Diagnostic Tests

Test 1: Measure voltage at furnace

You’ll need a multimeter:

  1. Set Ecobee to call for heat
  2. At furnace control board, measure AC voltage:
    • R to W terminal: Should read 24-28VAC (heat ON)
  3. Set Ecobee to turn heat off (lower setpoint below current temp)
  4. Wait 1 minute, measure again:
    • R to W terminal: Should read 0VAC (heat OFF)
  5. If still reading 24VAC when heat should be off:
    • Problem is at thermostat (relay stuck) or in wiring (short)

Test 2: Isolate thermostat vs furnace

  1. Turn off power at breaker
  2. At furnace, disconnect W wire from control board
  3. Jumper R to W at furnace (using separate wire/jumper)
  4. Turn power on – furnace should run
  5. Remove jumper – furnace should stop
  6. If furnace doesn’t stop when jumper removed:
    • Furnace control board relay is stuck
    • Control board needs replacement
  7. If furnace stops properly:
    • Furnace is fine, problem is thermostat or wiring

Test 3: Bypass Ecobee completely

  1. Turn off power at breaker
  2. Remove Ecobee and wall plate
  3. Install old thermostat (or jumper R to W manually when you want heat)
  4. Test for several hours
  5. If heat control works normally with old thermostat:
    • Ecobee is faulty – contact warranty support
  6. If heat still won’t turn off:
    • Furnace control board issue

๐Ÿ“‹ Step-by-Step Troubleshooting Flowchart

Follow in this order:

  1. โœ… Emergency stop โ†’ Turn off furnace power switch if dangerously overheating
  2. โœ… Force reboot Ecobee โ†’ Remove from wall 30 sec, reattach (fixes 70% of cases)
  3. โœ… Check for active holds โ†’ Remove any holds or overrides
  4. โœ… Set to OFF mode โ†’ Does heat stop? If no, continue troubleshooting
  5. โœ… Remove Ecobee from wall โ†’ Does heat stop? If yes, Ecobee relay stuck
  6. โœ… Disconnect W wire at thermostat โ†’ Does heat stop? If no, wiring short
  7. โœ… Check equipment configuration โ†’ Correct heating type configured?
  8. โœ… Adjust temperature differential โ†’ Set to 1.0ยฐF to prevent short cycling
  9. โœ… Disconnect W at furnace โ†’ Does heat stop? If no, stuck furnace relay
  10. โœ… Call professional โ†’ If furnace relay stuck or wiring short can’t be found

๐Ÿ”‘ Key Takeaways

Most common fixes (DIY-friendly):

  1. Force reboot Ecobee – remove from wall 30 sec (70% success rate)
  2. Remove active holds – clear schedule overrides (15% of cases)
  3. Check equipment configuration – wrong heating type configured (10% of cases)

Hardware issues requiring repair:

  • Stuck Ecobee relay – warranty replacement needed
  • Shorted W wire – repair or replace wire run
  • Stuck furnace relay – control board replacement ($250-600)

Quick diagnostic decision tree:

  • Heat stops when Ecobee removed? โ†’ Ecobee relay stuck (warranty replacement)
  • Heat continues when Ecobee removed? โ†’ Wiring short or furnace relay stuck
  • Heat stops when W wire disconnected at furnace? โ†’ Short in wiring
  • Heat continues even with W wire disconnected? โ†’ Furnace control board failed

When to call a pro:

  • Furnace control board replacement needed
  • Can’t locate wiring short
  • Not comfortable with 24VAC troubleshooting
  • System involves gas connections

Cost expectations:

  • Ecobee warranty replacement: $0-50 (shipping)
  • Thermostat wire replacement: $100-300 (professional)
  • Furnace control board: $250-600 (part + labor)
  • HVAC diagnostic service call: $100-200

โš ๏ธ Important Safety Notes

Before working on your system:

  • Turn off power at breaker AND furnace switch
  • Let furnace cool if recently running (heat exchanger can be 400ยฐF+)
  • Don’t bypass safety switches – they prevent fires and carbon monoxide
  • If you smell gas – evacuate and call gas company/911

Signs you need immediate professional help:

  • Smell of gas or burning
  • Visible flames outside furnace cabinet
  • Smoke or soot around furnace
  • Carbon monoxide detector alarming
  • Furnace making loud banging/booming sounds
  • Cracks visible in heat exchanger

๐Ÿ’ฌ Still Having Issues?

If heat still won’t turn off after trying these solutions:

  1. Emergency action:
    • Turn off furnace power switch immediately
    • Don’t leave home with heat running uncontrolled
    • Open windows if overheating
  2. Document the problem:
    • Does heat stop when Ecobee is removed from wall? (Yes/No)
    • Does heat stop when W wire is disconnected? (Yes/No)
    • What does Ecobee screen show? (Temperature, mode, holds)
    • Any error codes flashing on furnace control board?
  3. Contact support:
    • Ecobee support: 1-877-932-6233 (for thermostat issues)
    • HVAC technician: For furnace control board issues
  4. Provide key info:
    • Ecobee model and firmware version
    • Furnace brand and model
    • Results of diagnostic tests above
    • Photos of wiring at thermostat and furnace

Most “won’t turn off” issues are either a simple reboot fix or a definable hardware failure – you can figure this out!