Issues with defrost binary sensor

[jeroen85]

System Health details

N/A

Checklist

• I have enabled debug logging for my installation.
• I have filled out the issue template to the best of my ability.
• This issue only contains 1 issue (if you have multiple issues, open one issue for each issue).
• This issue is not a duplicate issue of currently previous issues..

Describe the issue

I experience a lot of Defrost cases with my HP1 while it is not defrosting at all. It happens during start of the HP.

in my case it is caused by a small temperature difference of the water inlet and outlet sensor when the HP is not in use. This results in the power measurement becoming negative, exceeding -100W and triggering the defrost binary sensor.

Maybe some additional parameters should be checked to determine defrost situations?

Reproduction steps

N/A

Debug logs

N/A

Diagnostics dump

No response

[jeroen85]

As the heat power decreases up to -6000W during defrost I would suggest to change the threshold to something like -2000W instead of -100W

[patrickvorgers]

What I see in the code is that it uses the power and powerinput from the Quatt and not the waterdelta.
Can you create a graph of a longer period of the power and powerinput of HP1?

What I see in the graph currently that it probably has to do something with having a Quatt Duo. When HP2 is active HP1 is running on "low" power (less than 100W).

[patrickvorgers]

Looking at my own Quatt (don't have a duo), it seems like that changing the heatpower check to -2500 could do the trick.

Could you change in the file coordinator.py (custom_components/quatt) the computedDefrost function?
Especially the return statement which checks the ranges of the input and output power.
After the change you have to restart Home Assistant to activate the change.
Please check whether that fixes the issue for you.

    def computedDefrost(self, parent_key: str | None = None):
        """Compute Quatt Defrost State."""
        if parent_key is None:
            return None

        powerInput = self.getValue(parent_key + ".powerInput")
        powerOutput = self.getValue(parent_key + ".power")

        LOGGER.debug("%s.computedDefrost.powerInput %s", parent_key, powerInput)
        LOGGER.debug("%s.computedDefrost.powerOutput %s", parent_key, powerOutput)

        if powerInput is None or powerOutput is None:
            return None

        powerOutput = float(powerOutput)
        powerInput = float(powerInput)

        return powerOutput < -2500 and powerInput > 100

[jeroen85]

What I see in the code is that it uses the power and powerinput from the Quatt and not the waterdelta. Can you create a graph of a longer period of the power and powerinput of HP1?

The power is a calculated value within the CiC. It is the flow * heat capacity of water * T_waterdelta. As the T_waterdelta becomes slightly negative (-0,1 degC), the resulting power measurement also get's negative. This exceeds the threshold of -100W and triggers the defrost binary.

I will change the coordinator.py file, thanks for the suggestion!

[patrickvorgers]

What I see in the code is that it uses the power and powerinput from the Quatt and not the waterdelta. Can you create a graph of a longer period of the power and powerinput of HP1?

The power is a calculated value within the CiC. It is the flow * heat capacity of water * T_waterdelta. As the T_waterdelta becomes slightly negative (-0,1 degC), the resulting power measurement also get's negative. This exceeds the threshold of -100W and triggers the defrost binary.

I will change the coordinator.py file, thanks for the suggestion!

You are right that the CIC uses a similar formula as the Quatt integration when an external powermeter is used to calculate the produced heat computedWaterDelta * flowRate * 1.137888.

Great that you are going to test out the change. Please report back whether it fixes the issue. I will also apply the change myself and check the effects on a single Quatt. After some testing I will create a pull request (PR) for the change.

[jeroen85]

It worked as expected. Binary sensor indicated defrost when power was below -2500W.
No defrost for small power drops (for example the -233W around 12:00)

[patrickvorgers]

@jeroen85, I created a PR with the fix. Hopefully it will be merged soon.

[patrickvorgers]

Today, I was checking the defrost sensor and I saw that I don't get any negative power values anymore. After some investigation I saw that the CiC was upgraded to version 2.20.2.
Below is what I see currently and I suspect that it is a defrost:

• Power value is 0
• Waterdelta is negative

@jeroen85, could you check whether you see the same behaviour?

[jeroen85]

I will, unfortunately no defrosts these days