Extension Kit - how to make sure it is working properly?



I have Tado TRVs on several radiators all working very well. This year I decided to add the Extension Kit so that my boiler will turn off when it is not needed.

My setup:

I have 8 TRVs in different rooms, the Tado bridge and now the Extension Kit. My boiler is an old one, Immergas Eolo Mythos, powers up radiators + hot water (combi boiler). It has a setting for the temperature of the hot water in the radiators, currently set to 60 degrees Celsius. The Extension Kit is wired in "relay" mode.

Before the Extension Kit:

Each TRV is added to a room. Each room is set to a certain temperature. When the measured temperature is below what is set, the TRV in that room opens, so that hot water can go in and warm up the room. That in itself works pretty well. However, even if all TRVs are closed, instead of resting, the boiler is trying to keep the temperature to what is configured (60 degrees Celsius), which causes it to turn on and off, potentially burning money for nothing.

How I imagined it would be with the Extension set (desired state):

Same as above, but If no TRV requests heating, the boiler will be kept off, until heating is actually needed.

How it actually is:

The boiler is still fired up sometimes, even if no TRV requests heating.

My questions:

  1. Is what I described the expected way for the whole system to work?
  2. How can I test if the extension set is properly installed? It was installed by a "professional" but I could tell this is the first time he installs Tado and had to convince him that it will work and show him the jumper (he thought I purchased the wrong device).