Hello everybody,
I created a template so I can monitor my Delta T ( ΔT ). Simply said the difference of temperatures between two measuring points.
In my case this is the water-heating system in my floors.
My boiler has both outputs for supplied temperature and return temperature, so I created a template to calculate the difference between them.
- platform: template
sensors:
delta_t:
value_template: >
{{ '%0.1f' | format(states('sensor.actual_supply_temperature') | float -
states('sensor.return_temperature') | float) }}
unit_of_measurement: '°C'
friendly_name: Delta T
Now this works, but I always get these errors in my log:
Logger: homeassistant.helpers.event
Source: helpers/template.py:546
First occurred: 09:13:17 (1 occurrences)
Last logged: 09:13:17
Error while processing template: Template<template=({{ '%0.1f' | format(states('sensor.actual_supply_temperature') | float - states('sensor.return_temperature') | float) }}) renders=2>
Traceback (most recent call last):
File "/usr/src/homeassistant/homeassistant/helpers/template.py", line 1893, in forgiving_float_filter
return float(value)
ValueError: could not convert string to float: 'unknown'
During handling of the above exception, another exception occurred:
Traceback (most recent call last):
File "/usr/src/homeassistant/homeassistant/helpers/template.py", line 544, in async_render
render_result = _render_with_context(self.template, compiled, **kwargs)
File "/usr/src/homeassistant/homeassistant/helpers/template.py", line 2164, in _render_with_context
return template.render(**kwargs)
File "/usr/local/lib/python3.10/site-packages/jinja2/environment.py", line 1301, in render
self.environment.handle_exception()
File "/usr/local/lib/python3.10/site-packages/jinja2/environment.py", line 936, in handle_exception
raise rewrite_traceback_stack(source=source)
File "<template>", line 1, in top-level template code
File "/usr/src/homeassistant/homeassistant/helpers/template.py", line 1896, in forgiving_float_filter
raise_no_default("float", value)
File "/usr/src/homeassistant/homeassistant/helpers/template.py", line 1594, in raise_no_default
raise ValueError(
ValueError: Template error: float got invalid input 'unknown' when rendering template '{{ '%0.1f' | format(states('sensor.actual_supply_temperature') | float -
states('sensor.return_temperature') | float) }}' but no default was specified
The above exception was the direct cause of the following exception:
Traceback (most recent call last):
File "/usr/src/homeassistant/homeassistant/helpers/template.py", line 665, in async_render_to_info
render_info._result = self.async_render(variables, strict=strict, **kwargs)
File "/usr/src/homeassistant/homeassistant/helpers/template.py", line 546, in async_render
raise TemplateError(err) from err
homeassistant.exceptions.TemplateError: ValueError: Template error: float got invalid input 'unknown' when rendering template '{{ '%0.1f' | format(states('sensor.actual_supply_temperature') | float -
states('sensor.return_temperature') | float) }}' but no default was specified
and
Logger: homeassistant.helpers.template_entity
Source: helpers/template_entity.py:379
First occurred: 09:13:17 (1 occurrences)
Last logged: 09:13:17
TemplateError('ValueError: Template error: float got invalid input 'unknown' when rendering template '{{ '%0.1f' | format(states('sensor.actual_supply_temperature') | float - states('sensor.return_temperature') | float) }}' but no default was specified') while processing template 'Template<template=({{ '%0.1f' | format(states('sensor.actual_supply_temperature') | float - states('sensor.return_temperature') | float) }}) renders=4>' for attribute '_attr_native_value' in entity 'sensor.delta_t'
These are the only red fault errors in my log and like to get rid of them.
I understand the above errors show me what is wrong, I just dont understand it, and my google-fu is failing me in this matter.
Thanks for the help!