Blue LED 1 flash (slow blink) — EMS bus not connected

What does 1 flash mean?

The blue LED on the Gateway blinks once slowly, then pauses, repeating this pattern. This signifies that the Gateway has booted up but is unable to detect or connect to the EMS bus from your boiler or Heat Pump.

• EMS bus wires are not physically connected to the Gateway's terminal block.
• EMS bus wires are incorrectly wired, loose, or damaged.
• Issue with the boiler's EMS bus port or a problem on the boiler side.

Click steps to track your progress.

1. 1

   Verify that the EMS bus wires are correctly and securely connected to the Gateway's 2-pin green terminal block.

2. 2

   Check the connections at the boiler or Heat Pump side to ensure they are firm and correct.

3. 3

   Ensure you are not connecting both the jack and screw terminal for the EMS bus simultaneously, as this can cause a short circuit.