What should I check first when a device goes offline?
Work from the supply side towards the controller. Most off-line reports are resolved before any component is replaced.
| Possible cause | How to check | What to do |
|---|---|---|
| Power supply disconnected | Check whether the power LED is on | Restore power; inspect the distribution box |
| Main RCD tripped | Check the RCD handle position | Reset the RCD; if it trips again, look for leakage |
| AC-DC module fault | Measure the 12 V output with a multimeter | Replace the AC-DC module |
| 4G module hung | Check the network LED status | Remote-restart the module (AT+CFUN=1,1) |
| SIM out of credit | Check the SIM data balance | Top up or replace the SIM |
| Poor SIM contact | Remove and reseat the SIM | Clean the contacts and reinsert |
| Loose antenna connector | Inspect the SMA connector | Tighten or replace the feeder |
| Weak 4G signal | Read the CSQ value in the app | Fit a high-gain antenna or relocate it |
| MQTT server fault | Check whether other devices are offline too | Contact technical support |
| Controller board fault | Power-cycle with no recovery | Replace the controller board |
Related guides
Frequently asked questions
Do I need to register or leave an email to use these guides?
No. All troubleshooting and commissioning guides on this site are open pages with no form and no email gate. The full product datasheets are also open on the downloads page.
Do these pages publish spare-part prices or service fees?
No. These pages publish technical checks, wiring rules and procedures only. For spare parts, service terms or a quotation, contact [email protected].
Can a 4G outage stop the aerators from running?
No. The controller runs its closed-loop logic locally and still starts and stops aerators by dissolved-oxygen threshold when the cloud is unreachable; cached data is back-filled after recovery.
Where is the wiring diagram for the controller?
The TK Family Controller Integration and Wiring Guide is on the downloads page, together with the TK-4G-GW and TK-R12-SC4S-BG datasheets.