How To Fix It

What Are Zoned HVAC System Problems?

A zone HVAC system consists of quite a few components and, at one point, any of those can start to malfunction.,

The most common issues that you might have to deal with in case you have a zone HVAC system include faulty thermostats, malfunctioning control panel, leaky ducts, and stuck or faulty dampers. In the majority of cases, one of the thermostats would be to blame.

Zone HVAC System Problems

A zone HVAC system is a bit more complicated than a regular heating and cooling system and, naturally, you might have to deal with more problems.

Faulty thermostats

A bad thermostat is one of the most common issues when it comes to zone systems. This is the device that sends signals to the dampers and controls the operation of the whole system.

Generally, every separate zone in your house is going to have its own thermostat. So, the chances that something might go wrong will double or even triple.

Malfunctions of the control panel

The control panel is responsible for interpreting the signals sent to the ducts and for coordinating the airflow through the system. Faulty wiring or issues with electrical power are the most common problems associated with this component.

Read: Why HVAC Maintenance Is Important?

Leaky ducts

A zone HVAC system includes ducts and that’s why it is susceptible to all ductwork-related issues.

A gap in the ducts will make the system overwork and will affect how well the unit is able to heat and cool. Moreover, holes in the ductwork can let dust and various pollutants into the system.

Stuck dampers

Dampers are the main components of a zone HVAC system. If one of these mechanical devices gets stuck, a zone of your house will stop receiving conditioned air and the system might start to overwork.

Read: Why HVAC Not Working?

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What Is the Major Cause of Thermostat and Zoning Failure?

If you’re experiencing an issue with the zoning system, the chances are high that there is something wrong with one of the thermostats. So, it is recommended to start the troubleshooting process with these devices.

  1. If the display is blank, then you might have to change the batteries or reset the thermostat.
  2. Double-check the thermostat settings and make sure that you have installed the device in a good location (sunlight and heat-generating devices can affect the accuracy of the readings).
  3. Faulty wiring can also be to blame. Either the thermostat wasn’t wired properly from the very beginning, or one of the connections had gone loose or had become damaged.

Sometimes the issues might be with the actual thermostat that is simply not a good match for your HVAC system.

How Do You Troubleshoot a Zone Board?

Before troubleshooting your zone board, make sure to check the thermostats, filters, and other standard mechanical equipment.

If you don’t feel comfortable working with voltmeters and wires, then you might want to leave the job to a professional.  

Why Is My AC Zone Not Working?

Your zone HVAC system won’t be able to work properly if the air can’t freely flow through the unit. This can happen due to a dirty filter or duct, so you might want to check those.

Read: Quietest HVAC System

Upstairs AC Zone Not Working

Check the air registers in the upstairs zone – they shouldn’t be closed off, blocked, or dirty. Also, make sure that the filters are clean.

The upstairs part of the zone HVAC system might not be working, if there is an issue with the ductwork in this part of the house, so you might want to check the ducts as well.

Dual Zone AC Not Working in One Zone

If your thermostat is functioning correctly, then it looks like the dampers that are responsible for that specific zone are stuck. This might happen if the elements simply got dirty or there is an issue with the control panel.

How Do You Troubleshoot Zone Dampers?

You first need to figure out whether you have manual or automatic dampers (the former have an adjustment handle and the latter have a control motor).

Read: Why HVAC Is Important

What Is a Zone Damper Fault?

‘Zone damper fault’ usually means that a particular zone in your HVAC system is not working. This might happen, if:

  • The airflow settings are too low
  • There is a loose connection
  • The zone motor has gone bad
  • The zone cable or port is faulty

How Do You Test a Vent Damper?

If you have a manual damper, place the handle in the closed position, turn the system on, and check the airflow.

If you have an automatic damper, simply turn the HVAC system on and check the airflow at the registers. Low airflow might indicate a faulty damper.

Read: Does HVAC Filter Direction Matter?


How Long Do Zone Dampers Last?

With proper maintenance, HVAC dampers can last for around 15-20 years.

How Do I Know If My Zone Damper Is Open or Closed?

Sheet metal dampers have a small wing nut. The bolt that goes through it has a flat spot that you can use to figure out the position of the dampers.

In the majority of cases, if you have noticed that the wing nut is in a horizontal position, then the damper is open and vice versa.

How Do I Manually Open Zone Damper?

Opening manual dampers is relatively easy, but what about motorized ones?

You might have a motor with a release button. In such a case, all you would have to do is push the button and turn the shaft by hand (don’t forget to disconnect the electric flow to the motor).

How Much Does a Zone Board Cost?

A zone control board kit can cost you around $450.

Depending on the zone control panel capabilities, it will cost between $115 and $200. Zone sensors are usually priced at around $25-$45, while power dampers can cost up to $325 (the price will depend on their size and shape).

What Does Purge Mean on Zone Board?

Many newer systems purge the system on startup. This means that the unit is getting its internal lines and hoses cleared out.

How Much Does Damper Replacement Cost?

The cost of the element and the labor can range from $100 to $600. On average, be prepared to pay around $350 for replacing a motorized damper

Do Dampers Damage HVAC?

If you have a zoned HVAC system with variable speed equipment, then the dampers won’t be damaging the system as there will be small amounts of air passing through the ductwork when the zone calls for it.

This is not what happens if you close off a zone in a single-speed system. In fact, the static pressure in such a case might be too intense and this will eventually lead to damage.

How Often Should Dampers Be Replaced?

You might not have to replace your dampers at all as the lifespan of the whole HVAC system pretty much equals to that of the dampers.

But you would certainly have to make sure that all the elements in the system undergo proper and regular maintenance.

How Do You Adjust Dampers for Winter?

To efficiently heat your house in the winter, you might want to redirect more warm air into the lower part of the building. SImply adjust the dampers to send more heat to the first floor as the warm air is going to rise anyway.