Danfoss Ally TRV not enough PI %

Hardware
1

Hi, I just started using Danfoss Ally TRVs throughout the home. My setup is to collect request for heat true in node red and activate the gas boiler. I also connected external temps to most of them and updating the TRVs also through node red in the correct format (4 digits)

Problem is, some of the thermostats set request for heat true but do not open the valve enough, so the radiator is still cold.

I was expecting that the TRV would keep opening the valve if it sees that no change is happening but this doesn’t seem to be the case. I notice that my valves/radiators need about 40% + in order to get warm.

Anyone else having similar experiences?
Should i wait for 1-2 weeks as I understand the thermostats have a learning phase?

2

Hello,

Those smart part of the radiator valves is unknown to me, it does sound however that once you send a command to ‘open’ the valves, they do not hold that position long enough. Can you send them a percentage of what you expect to get to?

Know that there are several blueprints out there to assist you in managing the temperature in your house, one of them: 🧠⁺ Smarter Thermostat

3

You can more or less send it the target temp. The problem i seem to have is how it gets there :slight_smile:

The PI heat demand or how much it opens the valve is decided by the TRV internally, cannot be set :frowning:

4

Since it is the valve that decides, I am going to assume it will read out a temperature and perhaps open in increments? (Last part is a total guess)
What happens if you send a higher temperature, say 3°C more (or 8°F)?

5

Many thermostats that have no external temperature sensor will use its internal thermometer to compute the need for heat, but this internal thermometer is often skewed do to being at the input pipe of the radiator and therefore reach the temperature before the room is heated up.
Sometimes just having the pipe heat up can be enough to make the thermostat turn off again.

I suggest you invest in some external temperature sensors for the rooms and then either use the Better Thermostat integration or make you own logic to control the thermostats.
I have done this myself and I read the temperature of the external temperature sensor, then calculate what the difference is between the sensors value and the target temperature.
That difference is then added to the current measured temperature of the thermostats internal thermometer and set as a target temperature for the thermostat.