Honeywell HZ311 Troubleshooting: Zone 2 And 3 Red Lights: [Solved]

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Be it hot or cold, air conditioners are a lifesaver. With zoned air conditioning, you can control the temperature in different parts of the house.

But a malfunction in the system can turn things around overnight. In zone control panels like Honeywell HZ311, you might see Zone 2 and 3 red lights indicating a malfunction.

The Honeywell HZ311 zone 2 and 3 red lights might pop up for several reasons. The low refrigerant level can be the problem. Also, your blower motor could be turned off or malfunction. Even a jammed damper or a frozen-up coil might be the culprit. However, the solutions are pretty straightforward.

That was just a quick summary. Let’s now go into troubleshooting a Honeywell HZ311.

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What Does the Zone 2 And Zone 3 Red Light Mean in Honeywell Hz311?

Honeywell Hz311 is a zoning panel used to keep an eye on the HVAC system of your house. When zone 2 and 3 red lights show up on the panel, it signifies the thermostat is not cooling or heating.

Several reasons can cause the system not to cool. It can be related to the blower motor, damper, or coil starting from a low refrigerant.

4 Reasons Behind Honeywell Hz311 Zone 2 & 3 Red Light

honeywell hz311 zone 2 and 3 red light

Reason 1: Low Refrigerant Level

This is the most common reason for the zonal red lights. If there isn’t enough refrigerant, the HVAC system won’t cool or heat as it should. Causing one of the zones to shut down.

The HZ311 purge light may also blink for this reason.

Solution: Recharging the Refrigerants

Recharging refrigerants can be done in a few steps-

  1. Wear safety gloves and goggles before proceeding 
  2. Locate the suction line and discharge line in the system. The suction line is used to fill up the refrigerant.
  3. Unscrew the bolt on the suction line. Loosen the screw inside with a hex key. It is important for filling the gas.
  4. The AC manifold gauge’s blue hose needs to be connected, so first unscrew the bolt on the left. Hook up the suction pump’s yellow hose.
  5. Vacuum the system to remove any moisture or air.
  6. Make sure all the AC manifold valves are closed. Attach the refrigerant tank to the yellow pipe.
  7. Turn on the air conditioner by opening the lower control knob. The compressor will begin operating in around four seconds.
  8. Repeat the process until the pressure reaches 60-70 PSI.

Do keep in mind that venting refrigerants during the process is illegal. You can be fined and may sue for this occurrence. 

Reason 2: Your Blower Motor Is Not Running

Another reason your HZ311 is showing red light is the blower fan could be malfunctioning. If the blower fan malfunctions, the cooling and heating cycle will not turn on. 

Hence, the red light will show up in the HZ311, indicating a problem. However, troubleshooting a blower fan is fairly easy. Discovering the actual reason requires a few minutes of your time.

Solution: Proper Wiring, Setting Thermostat, and Cleaning Components

First, check the wiring and harnesses of the blower motor. If there are broken wires, replace them. Tighten any loose wires if necessary. 

Secondly, make sure your thermostat is set and working correctly. A broken thermostat might disable the blower fan.

Lastly, check the blower vents, filters, and drive belts. Make sure the filters and vents are not clogged. If so, clean them carefully with brushes and clothes. It is as easy as cleaning a mini-split.

Drive belts must be replaced when they show signs of wear or damage. Do this as recommended by the manufacturer.

Setting Thermostat
Source: Energy Vanguard

Reason 3: Your Dampers Are Not Opening

Another reason for the red light could be your dampers. If your dampers are not opening, it could prevent airflow. Thus, zone 2 and 3 will show you red light warnings. 

The zonal dampers are usually opened by power operation or they are spring shut. It works on static pressure. 

The damper on the HZ311 is automatically controlled, and a control motor operates it. Fixing it is no difficult task.

Solution: Replace the Damper

To troubleshoot your HVAC dampers, follow the ductwork and figure out the registers. Find out the register airflow when the system is working. 

To test the airflow, you should activate the system and look for less airflow than usual. The damper can be bad if there is a small amount of airflow with faulty temperature readings. Professional assistance is required to replace the damper.

If you’re an HVAC DIYer, you can replace the damper yourself. In that case, here are some of our recommendations-

Reason 4: You Have a Frozen up Coil

Another key reason is a frozen-up coil of HZ311. AC coils can freeze up any time of the year and can cause major issues. 

Inadequate ventilation is the most typical cause of this problem. Dirty filters and damaged ductwork can cause airflow problems. Because of this, the coil won’t retain its heat.

Even leakage of the refrigerant can cause the coil to become frozen solid. Fixing the problem won’t take too much effort on your part.

Solution: Cleaning Air Filter

Ensure the air filter is clean and fresh. Clogged air filters jam the flow and freeze up the coil. Replace the filter if it needs a replacement.

To reduce energy use, switch off the thermostat and activate the ventilation system. This will allow warm air from within to circulate and defrost the coil.

You can also turn on the defrost mode to deice the frozen coil. However, do read the instructions before proceeding. You might also need to purge your Honeywell HZ311.

Honeywell HZ311
Source: Arista Air Conditioning

Frequently Asked Questions (FAQs)

What Does Purge Mean In Honeywell Hz311?

Purge is the process of cleaning internal pipes and hoses of the Honeywell HZ311 system. This is done when the new refrigerant is charged. But, in the Honeywell AC unit, it is done during startup. This ensures a safe and clean operation of the system.

Should My HVAC Damper be Opened or Closed?

The dampers on your HVAC system should be opened during the summer and closed during the winter. The heat rises naturally when the upstairs dampers are closed in the winter. This is done once the item has been stored in the basement.

How Does a 3 Zone HVAC System Work?

A zoned HVAC system divides your home into multiple zones. These zones are controlled by their thermostat. This allows you to individually set the temperature of different zones. Thus, you can set the desired temperature in your room. This is not available in single-zone HVAC systems.


This concludes our discussion on Honeywell HZ311 zone 2 and 3 red lights.

Make sure you check your air conditioner regularly to avoid sudden problems. Otherwise, it might give you a lot of hassle in the long run.

See you soon.

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