ᐅ Brötje BWL Neo 8 – Issues with the Settings

Kati2022 schrieb:

At temperatures around 10°C (50°F), the pump cycles like crazy instead of reducing its output.

Yes, I can believe that. The heat pump is too large and can’t modulate down enough. Its minimum output is already way too high for your house.

Kati2022 schrieb:

The heating technician says "this is normal."

Yes, that’s because they installed an oversized heat pump. A smaller one would still cycle occasionally, but at around 10 degrees it might cycle only 3–5 times per day, if at all.

Have you had a room-by-room heat load calculation done with your desired temperatures? Otherwise, you can’t properly size the heat pump.

I’m afraid the technician is working with a “this is how I’ve always done it” approach and “my job is done when the house is warm—no matter how.”

Currently, it should look more like this:

These are two cycles at the current 8°C (46°F). Cycle 1 is from 1:00 to 6:30 (the peaks show defrosting, where the Panasonic inevitably uses the electric heater), cycle 2 is from 11:00 to 13:30.
Between 7:00 and 8:00 there is hot water demand; the other peaks come from the electric car and from the washing machine starting at 11:30.

Kati2022 schrieb:

The system was also commissioned by a Brötje technician.

Then include him as well. Even if it might cost a bit of money. But what the heating engineer says is nonsense.

nordanney schrieb:

Then include it as well. Even if it might cost a bit of money. But what the heating technician says is nonsense.

Yes, that’s exactly what I plan to do now. I already know the heating technician is talking nonsense.

We don’t have a room-by-room heat load calculation, only one from the energy consultant. The energy performance certificate states the maximum heating load (including domestic hot water) as 5.8 kW.
I just found out that the Brötje boiler can modulate down to about 2.5 kW. If mine were doing that, the firing cycles would definitely be longer. But mine is always running at almost 7 kW and won’t reduce. Is there anything in the settings to consider?
Here is a chart from today.

Kati2022 schrieb:

The heating engineer says that for the warranty, he has to follow the manufacturer's specifications...

Yes, but Brötje also allows operation without a buffer tank, as long as, for example, ERR is omitted. And honestly? If the heat pump keeps running like this and breaks down in two years, no one will cover the warranty anyway, because they will probably say: oversized or operated incorrectly. That’s at least what I would expect in such a case.

Kati2022 schrieb:

We don’t have a room-by-room heat load calculation, only one from the energy consultant. The energy certificate states that the maximum heat load (including domestic hot water) is 5.8 kW.

Then a heat pump with a maximum capacity of 5 kW should be chosen, not one as large as what you have.
But as I said, a proper room-by-room heat load calculation should (MUST, if the heating engineer does their job correctly) be carried out. This calculation (including the desired room temperature you want) is used to size the underfloor heating (spacing, pipe dimensions, circuit lengths) and to perform the hydraulic balancing.
You might want to ask the heating engineer for the calculations just for reference.

Kati2022 schrieb:

Is there anything to consider in the settings here?

Sorry, I don’t have any experience with this device yet. So I can’t help with the settings. Sorry.

HAAAALLLLOOOO :-)

Your heat pump is probably oversized, and there are better models available now. However, you still have a good one here ;-)
It modulates both the flow rate and the output!

Which mixing valve is installed? Please provide a photo if possible.
A significant energy consumer that frequently interrupts the heating cycles is the domestic hot water (DHW) production. I run it once a day, directly after the utility company peak load management period (EVU lockout), and only up to a maximum of 45°C (113°F). This way, the heating cycles can run continuously from start to finish.
Important to know: The Brötje “buffer tank 100L (26 gallons)” is actually a hydraulic separator!

Here are the first steps to take:

1. Set all ERR (thermostats) on the walls to the highest setting.
2. Main menu --> User level --> Code 0112
3. Heating circuit --> Parameters --> Set mixing valve target value to "No"
4. Heating circuit --> Heating curve (check which limit is set) to 20/25/27
5. DHW production --> Set to once a day, preferably immediately after the EVU lockout
6. Disable night setback

@Alessandro

Good thing you got in touch.
We’re going on holiday for two weeks starting tomorrow. I think I’ll only begin with the adjustments in January. I hope you’ll help me with that. Unfortunately, my heating technician is completely unreliable.

I know the pump is oversized. But I can’t change that now and have to make the best of it.
Please tell me first how much your pump modulates its output? For example, today with the warmer temperatures, how many kW is it running at for you? How often does it switch off? Mine cycles like crazy and always runs at about 7 kW.
We have the domestic hot water preparation under control. It switches on once a day, heats up to 47°C (117°F), and that’s fine. That’s enough for us. Hot water consumption is about 37 kWh of electricity.

Here is a screenshot from today