What Is the Major Cause of Thermostat and Zoning Failure?

Ideally, you would want to invite a professional to deal with any zoned HVAC system-related issues. But if you are confident in your skills, then you can attempt to solve the problem on your own.

The most common causes of thermostat and zoning failure are issues with the thermostats – the settings or improper wiring might be to blame. The other common issue includes problems with dampers (they can get stuck or the motor might fail); thankfully, malfunctions of the zone control panel are relatively rare.

What Is the Major Cause of Thermostat and Zoning Failure?

Here are the most common issues that the homeowners might have to deal with if they have a zoned HVAC system:

Problems with the thermostats

If your HVAC unit is not working correctly, then one of the thermostats can be to blame. Check the settings and the wiring; you should also ensure that the thermostat’s location is not affecting its accuracy.

Read: Ecobee Lite 3 Vs. Ecobee Smart Thermostat: Differences, Worth Of Upgrade?

Issues with the dampers

You can’t take advantage of your zoned HVAC system if there is something wrong with the dampers. These elements can stop working if there is a physical obstruction that is preventing them from functioning properly or if the damper motor is damaged.

Leaky ducts

The majority of zoning systems have ducts. This means that leaky or disconnected ducts can become a problem at one point, and the system will stop being as efficient.

Malfunctions of the zone control panel

If the panel is not receiving adequate power or if there is a wiring issue, then the component won’t be able to communicate with the rest of the equipment. 

Read: Why Ecobee Thermostat Runs For 5 Mins And Then Shuts Off?

What Causes Thermostat to Fail in House?

Unfortunately, thermostat failure is not an uncommon problem. Here are the main reasons why a lot of homeowners have to deal with such issues:

  1. Broken or damaged temperature sensors
  2. A dirty thermostat
  3. Poor location
  4. Wrong installation
  5. Improper settings
  6. Loose wiring
  7. Power issues or dead batteries

What Is the Problem with Thermostats?

Sometimes the actual thermostat is the problem. In case you are an owner of a zoned system, you have to make sure that the thermostat is compatible with the HVAC equipment.

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There are special multizone smart thermostats that’ll help make sure that the system works the way it should. 

Read: Can I Use An Ecobee Thermostat In An RV?

What Are the Symptoms of Thermostat Failure?

If you have noticed any of the signs mentioned below, then it looks like it’s time to replace your thermostat:

  • The HVAC system is short cycling
  • The thermostat is incorrectly reading the temperature
  • Your energy bills have recently skyrocketed
  • The thermostat can’t maintain a constant temperature
  • You have had the device for 10 years
  • The thermostat is not responding to the change in settings

What Does Zone Damper Fault Mean?

‘Zone damper fault’ typically means that a zone in your house stopped working (the HVAC system is not able to properly heat or cool the area). In such a case, the damper would be to blame.

This element will stop responding to the thermostat’s signals in case there’s a loose wire, a physical obstruction to the damper’s movement, or if the motor had gone bad. 

Read: Can You Use Multiple Ecobee Thermostats In The Same House?

Why Is One of My AC Zones Not Working?

If one of the zones in your multizone HVAC system is not working, then the issue is either with the corresponding thermostat or with the dampers that are responsible for that part of the house.

In case the AC zone that is not working is located on the upper floor, you might want to try setting the desired temperature two degrees lower than that on the first floor. Heat naturally rises and your second floor is going to feel warmer even if the whole system is working properly. 

Why Are Some of My Heating Zones Not Working?

You would have to check the thermostat and the dampers. If these components are fine, then you might want to double-check if the HVAC system is large enough for your house.

Bad insulation might also be to blame as any heating system is going to struggle to keep a house with poor insulation nice and warm. 

Read: How To Fix Ecobee Thermostat Connection Problems?

How Do You Troubleshoot a Zone Board?

If you have already checked the thermostats and the dampers and you are sure that your ducts are in great condition, then the zoning board might be the cause of zoning failure in your case. 

  1. Check for 24V from the calling terminal to “C’ – the thermostat might simply not be sending the right signal.
  2. Use a voltmeter to verify the presence of panel input control voltage (the reading should be between 22 and 27 VAC).
  3. If the voltage reading is within the zone indicated, then use the voltmeter to check the internal voltage supply of the PC board.
  4. If the equipment is not responding to the board, even though the LED lights are indicating a call, you should test the output relays by jumpering or using an ohm or a voltmeter test.

How Do You Troubleshoot Zone Dampers?

  1. Start with a call for heating or cooling from all zones
  2. Assess how the system is performing and take note of the registers that are not letting as much air through.
  3. Find the damper that is responsible for this zone; you might have to pull the damper out of the duct.
  4. Inspect the element, and make sure that there is no dirt or rust.
  5. Use a multimeter to check, if the damper is receiving 24V.
  6. If nothing happens once the element receives the necessary voltage, then the damper motor has gone bad.


How Long Does a Thermostat Last in a House?

The majority of thermostats can last for around 10 years, but replacing the device more often is recommended if you don’t want the thermostat to become outdated. 

Where Is the Reset Button on a Thermostat?

Resetting the thermostat is usually one of the easiest ways to deal with a lot of thermostat-related issues. 

Plenty of devices have a designated reset button that you would have to push and hold for around 5 seconds. If your thermostat doesn’t have such a button, you can try inserting the batteries backward and then putting them back in place.

How Much Does It Cost to Replace a House Thermostat?

Smart multizone thermostats can cost up to $600.

How Do I Test My Thermostat?

To test if your thermostat is functioning correctly or not, you should:

  1. Turn off the power to the HVAC system.
  2. Remove the thermostat wires from the terminals.
  3. Twist the ends of the bare wires together.
  4. Turn on the HVAC system. If the blower turns on, then the thermostat is defective

What Is Zone Control System?

The zone control system consists of three main elements:

  • The thermostats
  • The dampers
  • The control panel

The system uses the thermostats to connect to the control panel and then tells the dampers to either open or close. In a nutshell, the zone control system is the thing that allows you to control the temperature across all the rooms in your house.

How Do You Reset a Zone Damper?

You might want to reset the thermostats to see if that helps. Dampers can’t be reset, but you can adjust them to close or open less when power is applied.