This guide covers the physical changeover steps for connecting a new TekOnline 4-Zone Wall Controller to an existing 24V AC zone-control setup.
The aim is to make the swap controlled and easy to check: first prove the existing controller is being fed by about 24V AC, then remove power, prove the 24V AC feed is off, move the RJ11 zone cables carefully, power the new controller, and test each zone one at a time.
Before You Start
You will need:
- the new TekOnline 4-Zone Wall Controller
- a multimeter set to AC volts
- a small screwdriver if your 24V AC supply uses screw terminals
- labels or masking tape for the zone cables
- a phone or laptop if you are also setting up Wi-Fi and Home Assistant
Safety First
The wall controller is designed for low-voltage 24V AC zone-control wiring. Do not work on mains wiring.
If you are not sure which wiring is low voltage, stop and get a licensed technician or electrician to check it.
Before unplugging zone cables or moving the controller, always remove the 24V AC supply and confirm it is off with a multimeter.
Step 1: Confirm The Existing Controller Has 24V AC
Before disconnecting anything, confirm the old controller is actually being powered by a low-voltage 24V AC supply. TREAT EVERYTHING LIKE HIGH VOLTAGE UNTIL YOU PROVE OTHERWISE
Set your multimeter to AC volts.
With the system still powered, measure across the two supply wires feeding the existing controller.
You should see roughly 24V AC. A reading in the low-to-mid 20V AC range is normal for many HVAC zone-control transformers.
This check helps confirm the system is the right type for the new controller before you start moving cables.
If you do not measure 24V AC, stop and confirm the wiring, transformer, and system type before continuing.
Step 2: Turn Everything Off
Turn off the air-conditioning system at the controller or isolator as you normally would.
Then unplug or disconnect the 24V AC supply feeding the zone controller.
Do not rely only on the screen being off. Confirm the supply is actually dead before touching the wiring.
Step 3: Confirm The 24V AC Supply Is Off
Set your multimeter to AC volts.
Measure across the two 24V AC supply wires that normally feed the controller.
You should see close to 0V AC.
If you still see around 24V AC, the transformer or system supply is still live. Stop and find the correct plug, breaker, fuse, or isolator before continuing.
Step 4: Label The Existing RJ11 Zone Cables
Before unplugging anything, take a photo of the existing wiring.
Then label each RJ11 cable:
- Zone 1
- Zone 2
- Zone 3
- Zone 4
If the old controller has labels, copy those labels onto the cables. If it does not, trace the cable positions and mark them before removal.
This step matters because RJ11 plugs can all look the same once they are unplugged.
Step 5: Unplug The RJ11 Zone Cables
Press the small latch on each RJ11 plug and pull it out gently.
Do not pull on the cable itself. Hold the plug body if possible.
Remove:
- the Zone 1 RJ11 cable
- the Zone 2 RJ11 cable
- the Zone 3 RJ11 cable
- the Zone 4 RJ11 cable
Keep the cables separated so they do not lose their labels.
Step 6: Remove The Old Controller
Once the 24V AC supply is proven off and the RJ11 cables are unplugged, remove the old controller from the wall or mounting position.
Keep any screws or mounting hardware if you need them for the new controller.
Step 7: Mount The New 4-Zone Controller
Place the new controller in the same location or the planned mounting spot.
Make sure the RJ11 sockets and 24V AC input are accessible before tightening everything down.
Avoid crushing or sharply bending the RJ11 cables behind the controller.
Step 8: Plug In The RJ11 Zone Cables
Plug the labelled RJ11 cables into the matching zone ports on the new controller:
- Zone 1 cable into Zone 1
- Zone 2 cable into Zone 2
- Zone 3 cable into Zone 3
- Zone 4 cable into Zone 4
Push each plug in until it clicks.
After plugging them in, gently pull each plug to confirm it is latched.
Step 9: Reconnect The 24V AC Supply
Reconnect the 24V AC supply to the new controller.
Check that the 24V AC wires are secure and that no bare wire is exposed outside the terminal or connector.
Once everything is seated, power the 24V AC supply back on.
Step 10: Check The Controller Powers Up
Wait about 15 to 30 seconds.
The controller should power up and the buttons or status lights should become available.
If the controller does not power up:
- turn the 24V AC supply off again
- confirm the transformer output with the multimeter
- check the 24V AC connection at the controller
- confirm the wires are in the correct input terminals
Step 11: Test Each Zone
Test the zones one at a time.
Press Zone 1 and confirm the expected damper or zone responds. Then turn it off and repeat for:
- Zone 2
- Zone 3
- Zone 4
If a zone opens from the wrong button, turn the 24V AC supply off again and swap the labelled RJ11 cables to the correct ports.
Step 12: Set Up Wi-Fi And Home Assistant
If this is the first time the controller has been powered at your site, it may create a setup hotspot called:
TekOnline 4 Zone Setup
Join that Wi-Fi network from a phone or laptop and open:
192.168.4.1
Enter your home 2.4 GHz Wi-Fi details, save, and let the controller reboot.
After that, add the controller in Home Assistant through Settings > Devices & Services.
Look for the discovered ESPHome device, or add it manually by IP address if needed.
Final Checks
Before leaving the job, check:
- the 24V AC input is secure
- all RJ11 plugs are latched
- each button controls the expected zone
- the controller is mounted firmly
- Home Assistant sees the controller if you are using it
Firmware Download
Looking for the latest YAML to flash? Download Firmware v2026.05.07
Leave a Reply