Sensor attribute string: Can't convert to number for graphing

Hello and welcome to the forum. Please edit your post and format your pasted config correctly, see: https://community.home-assistant.io/t/how-to-help-us-help-you-or-how-to-ask-a-good-question/114371#oneone-format-it-properly-16

Also please post your full sensor config. There is quite a bit of information provided by that error that is not shown in your sensor config.

Now, to your problem. Go to Developer Tools → States and find your sensor. What appears in the State column?

The error is saying this: state: 27.241627’

Notice the quote at the end?

If that is shown in developer tools you need to get rid of it for the state to be considered a number. You can do this:

state: "{{ state_attr('sensor.my_home_circuit_0_state', 'heating_circuit_flow_setpoint')|replace('’', '') }}"

It may be that type of “fancy” quote is there becaues of your lack of formatting. In which case the template should be:

state: "{{ state_attr('sensor.my_home_circuit_0_state', 'heating_circuit_flow_setpoint')|replace(''', '') }}"