Troubleshooting Your Honeywell Pro T755 Smart Thermostat

The Honeywell Pro T755 is a popular smart thermostat that allows users to control their home’s heating and cooling system remotely using a smartphone app. While these Wi-Fi enabled thermostats offer many conveniences, they can sometimes malfunction or encounter connectivity issues. This comprehensive guide will walk you through the most common Honeywell Pro T755 problems and provide step-by-step troubleshooting advice to get your thermostat working properly again.


The Honeywell Pro T755 is part of Honeywell’s T-Series line of smart thermostats. Key features include:

  • Remote access and control via the Honeywell Home app
  • 7-day customizable scheduling
  • Geo-fencing technology to automatically adjust temperature when you leave or return home
  • Compatibility with Amazon Alexa, Google Assistant and other smart home platforms
  • Advanced sensors to detect occupancy and adjust heating/cooling accordingly
  • Energy-saving features like Smart Recovery and Early-Onâ„ ̆

While the Pro T755 delivers powerful functionality when operating correctly, technical problems can arise like any complex electronic device. Troubleshooting your thermostat properly is key to resolving issues quickly with minimal headaches.

Common Honeywell Pro T755 Issues

common honeywell pro t755 issues
Common Honeywell Pro T755 Issues

Before delving into specific troubleshooting steps, these are some of the most frequent complaints reported by Honeywell Pro T755 owners:

Display Screen Problems

Issues like the screen not turning on, display staying blank, screen freezing/unresponsive, etc. Typically caused by power delivery problems.

Temperature Control Malfunctions

Problems like the thermostat not following the set temperature schedule, unpredictable heating/cooling, failure to automatically change modes as programmed. Often due to configuration errors.

Connectivity Problems

Inability to connect the thermostat to the Honeywell Home app or your Wi-Fi network. Commonly attributed to wireless interference or router incompatibility.

Fan Function Errors

Fan running inconsistently or not at all. Fan settings like “on” vs “auto” not functioning properly. Usually a wiring problem.

Battery Problems

Frequent low battery alerts or thermostat losing settings when batteries die. Thermostat may be drawing too much power or battery contacts are soily.

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Now let’s explore these common Pro T755 problems in greater detail, along with troubleshooting steps to get your thermostat working properly again.

Troubleshooting Honeywell Pro T755 Display Screen Issues

If your Pro T755’s display screen is remaining blank or having problems turning on, there are a few things to check:

Make sure the thermostat has power – Confirm that the display screen flashes when you first apply power. No flashing indicates a wiring problem. Also try new/fresh AA batteries.

Check the wiring connections – Loose wire connections at the thermostat terminals can prevent the display from powering on. Tighten all wires securely.

Test the C-wire for power – Use a multimeter to test for 24-30 V being supplied through the C (common) wire. No power indicates a wiring issue.

Reset the thermostat – Press and hold the Pro T755’s reset button for 10-15 seconds with power disconnected. This can clear any software glitches.

Replace the thermostat – If all else fails, the display screen itself may have failed. Replace the Pro T755 with a new unit. Make sure to configure it from scratch.

Carefully going through these basic troubleshooting steps should isolate any display screen power problems. Contact a technician if you cannot get the screen to turn on.

Troubleshooting Honeywell Pro T755 Temperature Control

If your Pro T755 thermostat is not maintaining set temperatures or following its programmed schedule, try these troubleshooting tips:

Check the schedule is programmed correctly – Make sure comfort settings and schedule times are properly programmed. Edit if needed.

Look for temperature vs schedule conflicts – If a hold temperature overrides the schedule, it will control the temperature instead.

Make sure the thermostat is in the correct mode – Double check that the system mode (Heat, Cool, Auto) aligns with your expectations.

Change batteries – Low batteries can cause thermostats to lose their programs and settings. Replace batteries annually.

Check system switch settings – The Pro T755 system mode switch should match your HVAC type (conventional, heat pump, etc).

Inspect your HVAC equipment – Faulty heating or cooling equipment can prevent the thermostat from accurately regulating temperature. Schedule an HVAC inspection if needed.

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Reset to factory settings – Reset the thermostat completely to see if improperly configured settings were the issue. Re-program it afterwards.

Upgrade thermostat firmware – Install the latest Pro T755 firmware update in case a bug fix is available. Use the Honeywell Home app to check.

With some diligent checking and tweaking of settings, you should be able to resolve any temperature control problems with the Honeywell Pro T755. Call in an HVAC technician if issues persist.

Troubleshooting Honeywell Pro T755 Connectivity

Here are some tips for troubleshooting Wi-Fi connection and remote access issues with your Pro T755:

Reboot the thermostat – Cycle power to force a reconnection attempt with your Wi-Fi network.

Check the Wi-Fi settings – Confirm the correct network name and password. Re-enter them if needed.

Reboot your wireless router – Power cycle the router and modem to refresh the wireless connections.

Check for router firmware updates – Update to the latest router firmware, as incompatibilities can affect connectivity.

Verify the thermostat software is current – Install the latest Pro T755 firmware update via the app.

Move the thermostat closer to the router – Weak Wi-Fi signals can disrupt connectivity. Relocate the thermostat closer temporarily for testing.

Check for radio interference – Microwave ovens, wireless cameras, and other devices can potentially block Wi-Fi signals. Turn off interfering devices.

Factory reset the thermostat – As a last resort, reset the thermostat completely to clear any software glitches.

Following this structured tips list should get your Honeywell Pro T755 communicating again. If not, contact Honeywell support for additional remoted connectivity troubleshooting assistance.

Troubleshooting Honeywell Pro T755 Fan Issues

Problems with the fan running incorrectly or not at all are commonly caused by wiring problems. Here are some things to check:

Inspect the wiring connections – Loose or improperly connected wires at the thermostat terminals can lead to fan operation issues due to lack of power.

Test the fan independently – Use the thermostat’s fan test mode to isolate whether or not the issue is electrical.

Verify the fan mode – Switch between AUTO and ON fan modes to observe behavior. Problem could be mode related.

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Check the fan limit controls – The furnace fan will only run within specified temperature limits. Wider limits may be needed.

Replace the fan limit switch – If faulty, the fan limit switch inside the furnace should be replaced by an HVAC technician.

Change the fan control board – Furnace control boards can also fail and prevent the fan from operating. An HVAC pro can swap in a new board.

Upgrade the thermostat firmware – Install the latest Pro T755 update to potentially fix any thermostat-related fan bugs.

With some simple fan troubleshooting steps, you should be able to identify wiring, hardware, or settings issues impacting fan functionality on your Honeywell Pro T755. Call a technician for repairs if needed.

Troubleshooting Honeywell Pro T755 Battery Problems

troubleshooting honeywell pro t755 battery problems
Troubleshooting Honeywell Pro T755 Battery Problems

Frequent battery drain or loss of settings when batteries die usually indicates an issue with excessive power draw. Try these battery troubleshooting tips:

Clean the battery contacts – Use rubbing alcohol to clean the thermostat battery contacts. Corrosion can interfere with power delivery.

Check for wiring shorts – A short in the thermostat wiring can overdraw power from the batteries. An HVAC pro should inspect wiring.

Replace batteries annually – Use new alkaline batteries every 1-2 years for maximum life. Write install date on the batteries.

Choose better batteries – Opt for lithium or NiMH rechargeable batteries to increase battery life over alkalines.

Turn off access light – Disable the motion-activated display light to reduce power usage and battery drain when idle.

Enable Auto Schedule Resume – This returns to the schedule after a power loss. Minimizes usage when restoring settings.

Install a common wire – Connecting a C-wire provides constant power to eliminate battery reliance. Call an HVAC technician.

Add a transformer kit – This aftermarket adapter lets you connect a C-wire without rewiring. Quick plug-and-play installation.

Taking a few simple steps to optimize power management and reduce drain on the Pro T755’s batteries will prevent frequent battery-related issues. A common wire is the ultimate solution for continual power.


Troubleshooting common problems with Honeywell Pro T755 smart thermostats like display screen, temperature, connectivity, fan and battery issues is usually just a matter of working through some structured diagnostic steps. Carefully inspecting settings, wiring and configurations allows you to isolate and fix many typical glitches and errors. For more complex HVAC-related faults, the assistance of a trained technician will help get your thermostat operating reliably again. Refer to Honeywell support resources as well when troubleshooting tricky Pro T755 problems.

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