ᐅ New heat pump to replace oil heating with existing radiators

In der Ruine schrieb:

Gas boilers have this feature, yes.

At least with the major German manufacturers, nothing has changed in this regard. Behind the burner or the hydraulic station, it does not matter how the heat is generated.
The heating circuit with the higher supply temperature runs unmixed, while the other circuit has its own return flow mixed in. This then requires an additional pump group with a mixing valve and a circulation pump. The control system is basically the same as with the burner.

In der Ruine schrieb:

Quick question for the heat pump experts. Are there heat pumps with two heating circuits—high temperature and low temperature—for a combination of radiators and underfloor heating in the house? With gas boilers, this is common.

Yes, that is possible. Alternatively, you can use a single circuit if the temperature difference between underfloor heating and radiators is not too large. This can be managed by a moderate average temperature and properly adjusted hydraulics. This approach may allow you to avoid additional pumps, mixers, buffers, valves, and so on. But yes, having two separate circuits is also definitely feasible.

ajokr2025 schrieb:

The heating circuit with the higher supply temperature then remains unmixed, while the other circuit has its own return flow mixed in. This requires an additional pump group with a mixing valve and circulation pump. The control system basically works the same way as for the burner.

So, I will have the heat pump operating entirely in the high-temperature range, which means a lower seasonal performance factor. Thanks for the feedback.

Have you found the settings for the heating curve? What is currently set there?

It's not that simple. Pressing Adapt briefly once shows a "1," the value is set to 21, and I can change it. Pressing Adapt for two seconds shows a "2," the value is set to 14, also adjustable. Apart from that, I haven’t found anything to change the flow temperature. Pressing "Temp" multiple times shows all the measured values one after another (flow temperature—currently 43°C (109°F), outside temperature, water temperature, room temperature from the rooms where a sensor is installed). But I can’t change anything here.

Please take some time to look into hydraulic balancing.

Easier said than done. I feel a bit lost with this...

Today was my first conversation with Enpal. They plan to install a Bosch air-to-water heat pump CS5800i AW 12 OR-T.
They estimated about 3,000 liters (790 gallons) of oil consumption per year.
What especially caught my eye as an unexperienced layperson:
Environmentally friendly and future-proof with natural refrigerant R290 (propane)
- Pump group with mixing function for a consistent temperature in the second heating circuit

Total purchase price (gross) €38,790.00
Their price after subsidy is €21,335
179 monthly payments of €325.77

Enpal tip: Use the government subsidy for extra repayments! By applying the anticipated subsidy amount of €17,456.00 for early repayment, the monthly rate drops to about €179.17.
That’s exactly what I had in mind from the start.
The pension will cover it, and future generations will manage it later on. I’ve even dreamed about the Grim Reaper. 😱

The Enpal heat promise:

At least 20°C (68°F)
in every heated room –
even on particularly cold days¹
If needed, replacement
of your radiators or
underfloor heating manifold without additional costs (there are almost 20 radiators; on the phone I was told:
whether we replace one or 20, it makes no difference for you as a customer)

¹Particularly cold days refer to days when the outdoor temperature at the installation site of the heat pump reaches down to -13.1°C (9.4°F) (“standard outdoor temperature”).
²Enpal assesses the necessity based on specific local conditions, especially the results of the room-by-room heating load calculation.


¹Particularly cold days refer to days when the outdoor temperature at the installation site of the heat pump reaches down to -13.1°C (9.4°F) (“standard outdoor temperature”).

Can I be confident about this?
Best regards
Norbert

strzata schrieb:

This is not so easy. Pressing Adapt briefly shows a "1", the value is 21 and can be adjusted. Pressing Adapt for two seconds shows a "2", the value is 14, which can also be changed.

That’s at least a starting point. The operating manual shows the heating curve diagram.
Heating circuit 1: Value 21 means at 0°C (32°F) outdoor temperature, the flow temperature is about 62°C (144°F).
Heating circuit 2: Value 14 means at 0°C (32°F) outdoor temperature, the flow temperature is about 48°C (118°F).
At +10°C (50°F) outdoor temperature it is lower accordingly, and higher at freezing temperatures.
Now you just need to find out which one is heating circuit 1 and which is heating circuit 2 in your system. That should be easy to test with an infrared thermometer on the pipes.
As the next step, you can start gradually lowering the flow temperature of heating circuit 1. Because 60°C (140°F) is not very heat pump friendly. It might simply be set too high, and the thermostatic valves reduce the flow. The heat pump dislikes that even more than a high flow temperature. Ideally, you can run both circuits at the same flow temperature.

I am skeptical about the installment offer from Enpal. In the end, you pay more than with a straightforward contractor’s invoice.