Troubleshooting

Basic Troubleshooting

Gateway plugged in to service jack but…

…no LED at all

If the LED is always off, there either is no power or the firmware is wrong, corrupt or has a wrong setting.

  • No power on the Service jack -> Plug in a USB power adapter to the Wemos directly. The LED should start blinking now.

  • Buck missing or broken -> Plug in a USB power adapter to the Wemos directly. The LED should start blinking now.

  • You are shortcutting the bus or the jack. -> unplug the Gateway and wait 2 min before plugging it back in.

  • You are drawing too much current from the bus. -> Unplug the Gateway, remove all external components and and wait 2 min before plugging it back in.

  • No firmware or firmware update error -> Reload a stable firmware image.

  • LED is turned off in the firmware settings -> Log in to the web interface and turn it on.

…LED keeps blinking forever

If the LED keeps blinking forever this means it cannot find the EMS bus OR the WiFi network.

  • Boiler with no EMS bus -> The Gateway is only compatible with the EMS bus.

  • EMS wires not connected or faulty -> Reconnect the jack cable or otherwise connect the screw terminal of the Gateway to the thermostat wires.

  • WiFi network disconnected.

…LED turns solid but start blinking again after a while.

In this case the EMS bus was found at some point, but due to either intermittency problems the communication was lost. Or the Gateway lost its connection to the WiFi network.

  • Bus wires not connected properly -> Reconnect the EMS bus wires.

  • Perhaps the Wemos is not getting enough power and is rebooting. -> Remove external components and try again.

…LED turns solid but web interface says ‘TX not working’.

In this case the EMS bus was found, but the Gateway cannot communicate with the bus.

  • Bus wires not connected properly -> Reconnect the EMS bus wires.

  • Service jack cable not connected properly -> unplug and replug the cable, reboot the Gateway.

  • TX mode is wrong -> For some boilers TX mode 1 is not the correct mode, try mode 2 or 3.

…LED is blinking or is solid but cannot connect to the web interface or with Telnet.

This is likely caused by network communication issues.

  • You are not connecting to the right IP or if using Telnet not on port 23 -> Change to the IP address of the Gateway and to port 23.

  • Your laptop (with Telnet) is not on the same network as the Gateway -> The Gateway should be on either your home network or it is in access point mode. In the latter case connect your laptop to the ‘ems-esp’ Wi-Fi network.

…the boiler reboots once on insertion of the cable

This usually happens when you insert the cable into the boiler and then into the Gateway. If the reboot happens once, you can ignore it.

…the boiler reboots continuously or intermittently

In this case the cable does not fit properly on either the boiler side or the Gateway side. Press the cable firmly into the connector or try another cable.

Gateway connected to the EMS wires but…

…the boiler reboots continuously or intermittently

  • Shortcut of the wires or not enough power on the bus. Check the wires. Try the service jack or a USB adapter.

…the boiler or thermostat gives an error code like BUS ERROR or A01, A51

  • There is not enough power available on the bus for the Gateway. Try the service jack or a USB adapter. If you have a module like a solar or mixer module with a BUS OUT terminal you can connect the Gateway there.

…the boiler starts heating by itself

  • Some boilers like the Bosch Condens 2500 accept either a on/off or EMS thermostat on the same terminal. If you have an on/off thermostat but you also connect the Gateway, the boiler detect a device on the bus and goes into EMS mode. But the Gateway is not a thermostat and the boiler starts heating anyway.

… the Gateway often disconnects from the WiFi

  • There is not enough power available on the bus for the Gateway. Try the service jack or a USB adapter. If you have a module like a solar or mixer module with a BUS OUT terminal you can connect the Gateway there.

  • You have bad WiFi reception where the Gateway is located.

Gateway connects to home network but MQTT is not connected

There can be a range of issues.

  • Wrong IP -> Set the correct IP of your MQTT broker. This is not always the same IP address as your home automation system.

  • Wrong user/password -> Make sure the MQTT authentication is set right or not at all.

  • Wrong port -> the MQTT port is 1883 by default. If you need to change this you have to build the firmware yourself.

  • MQTT broker is not running -> Make sure the broker is running on the target machine.

  • MQTT broker is not installed -> Install a MQTT broker like Mosquitto on the target machine.

MQTT is connected but seemingly no response

  • You are listening or publishing to the wrong MQTT topics -> verify the topic string.

The KM100, KM200 goes offline

In some cases the Web KM200/KM100/KM50/boilers with ethernet module goes into an offline mode when the Gateway is connected before the KM200 has properly booted. In the latest firmware you can set a delay for the Gateway. Go to Settings in the web interface and then find ‘TX delayed start’. Set it to 60 seconds.

More troubleshooting

For more troubleshooting see Proddy’s EMS-ESP Wiki 1. Or send me an email via the webshop.