Hello everyone,
Since I’m having trouble communicating with my heating installer, I’m asking you all:
What exactly is a “modulating heat pump”?
The Brötje BWL Neo 8 installed in our home is described by the manufacturer as modulating. However, since its commissioning in November 2023, it has been running at full heating capacity: about 7 kW. Although it operates with a good COP (average over the last two months is 4.4), that doesn’t help me much. Currently, it consumes a huge amount of electricity (sometimes well over 30 kWh per day). That doesn’t seem normal for a new build...
The installer says the pump only modulates the flow rates, not the output power. That can’t be right, can it?
I’ve noticed in this forum that @Alessandro has the same pump. However, his posts are somewhat old. Could someone help me out here?
To keep this post concise, I’m leaving out detailed information about the hydraulics and settings for now. These will follow if needed.
Since I’m having trouble communicating with my heating installer, I’m asking you all:
What exactly is a “modulating heat pump”?
The Brötje BWL Neo 8 installed in our home is described by the manufacturer as modulating. However, since its commissioning in November 2023, it has been running at full heating capacity: about 7 kW. Although it operates with a good COP (average over the last two months is 4.4), that doesn’t help me much. Currently, it consumes a huge amount of electricity (sometimes well over 30 kWh per day). That doesn’t seem normal for a new build...
The installer says the pump only modulates the flow rates, not the output power. That can’t be right, can it?
I’ve noticed in this forum that @Alessandro has the same pump. However, his posts are somewhat old. Could someone help me out here?
To keep this post concise, I’m leaving out detailed information about the hydraulics and settings for now. These will follow if needed.
Alessandro schrieb:
Don’t worry about the cycling frequency. Even if it cycles 15 times a day throughout the year (which it doesn’t, since it only produces domestic hot water in summer), the unit will last 25 years with 150,000 compressor starts! If you say so... 😉
As it looks, our values are similar.
What bothers me is the high heating curve. You mean I should disable the mixer’s heating curve. I’ll do that after the vacation and then we’ll see...
Here are my current values:
Then try lowering the compressor speed (VDmod) at 0°C (32°F). The BLW does not modulate between maximum and minimum possible output. Instead, the heat pump follows the compressor curve and reduces performance the closer it gets to the target return temperature. The power reduction can be adjusted using the control deviation parameter.
Remark: Compressor speed should never be below 15%. This was also set for me by the Brötje technician.
Remark: Compressor speed should never be below 15%. This was also set for me by the Brötje technician.