What could be the cause, this has been working few years, but now after within few core updates it has been like this :
It still works tho…
Prob is propably this:
Logger: homeassistant.components.modbus.validators
Source: components/modbus/validators.py:139
integration: Modbus (documentation, issues)
First occurred: 19:20:59 (1 occurrences)
Last logged: 19:20:59
Modbus enervent/sensor.Enervent Supply Air Temperature after HRC and heating address enervent8_holding_0 is duplicate, second entry not loaded!
Alltho, i have no idea where does “enervent8_holding_0” come from ?
I believe it’s originating from your climates, where you define “LTR5Z Temperature” to use the very same hreg address 8 as you are doing for “LTR5Z Supply Air Temperature after HRC and heating” in sensors. The newest modbus implementation in Home Assistant does not seem to accept multiple definations for a single address.
Anyone want to flag the typo in the error for Modbus?
It should say “one entity”, not “on entity”.
It’s in your definition for modbus in configuration.yaml. You have named your modbus service as ‘enervent’, the duplicated sensor is in address 8, holding is the default input_type for it.
That makes lots of sense.
This seems to be true, thank you !
May I ask how you resolved the issue? In my setup, I have done the same thing as you where I have one sensor reading from register 207 and I have a climate entity where I read and set the information in this register. Look at the code below.
I assume you may have used it for the same purposes, how did you work around this limitation?
modbus:
- name: vr400
type: tcp
host: x.x.x.x
port: 8899
sensors:
- name: vr400_temperature_setpoint
slave: 1
address: 207
scale: 0.1
precision: 1
unit_of_measurement: °C
scan_interval: 5
climates:
- name: vr400_temperature
slave: 1
address: 207
input_type: holding
max_temp: 22
min_temp: 12
offset: 0
precision: 1
scale: 0.1
target_temp_register: 221
temp_step: 1
temperature_unit: C
scan_interval: 5
I just commented another one out as i wasnt using it
Aha ok. I am using the climate one for setting the temp and writing to the register, while the sensor is there to show the data. I wonder if I can show the climate value instead of setting up a sensor for it, I will have to find out more. Thank you.
Or, if you just can bear that error message, it seems to work anyways 
This is a real problem for me. Just like you guys I use the same register once for a climate entity and once as a sensor. Why have this changed? It has been working for years.
Isnt it still working, and you can ignore warning msg ?
Happend to me also, any news on the issue ?