ᐅ Air-to-water heat pump combined with underfloor heating is not functioning properly
Created on: 22 Sep 2021 15:34
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_Ugeen_
Hello everyone,
We moved into our single-family house in the middle of the year and are now using our air-to-water heat pump (Daikin Altherma 3 R ECH2O) for the first time. In the rooms, we decided against the standard analog controllers and chose digital controllers instead. After several discussions with Daikin and the controller manufacturer, I now understand that a valve is only opened or closed when I want to increase the temperature or not.
With the Daikin system, I can set a target room temperature. According to Daikin, this target value does not represent the minimum temperature per room but rather the "preheating value," if I understand correctly. This value was previously set at 23°C (73°F).
In the bedroom, I set the digital controller so that heating only starts when the temperature drops below 18°C (64°F). Despite this setting, the room temperature has always been 22-23°C (72-73°F), although the digital controller shows that heating is off. After changing the target room temperature from 23 to 21°C (73 to 70°F), it got a bit cooler. However, in the bathroom, heating is supposed to activate below 23°C (73°F). The temperature there is 22°C (72°F), and the digital controller indicates that heating is active. Yet, the room does not get warmer, and the floor heating does not noticeably warm up either.
Conclusion: I still have not understood the logic behind the target room temperature setting. In our previous apartment, we also had underfloor heating with analog controllers that I could adjust higher or lower. That worked wonderfully, and I felt like I could control the temperature. Here, with the air-to-water heat pump, I don’t have that feeling. Also, the towel warmers do not get truly warm (only lukewarm), which Daikin says is normal even when the dial is set to 5. This is apparently because it is a low-temperature heat pump. Without the electric booster to warm the towel warmers, they are essentially ineffective. Is this normal? Could there be an error, or do I need to use completely different settings?
If anyone has experience with this topic, I would greatly appreciate your feedback. At the moment, I feel a bit lost on this subject.
We moved into our single-family house in the middle of the year and are now using our air-to-water heat pump (Daikin Altherma 3 R ECH2O) for the first time. In the rooms, we decided against the standard analog controllers and chose digital controllers instead. After several discussions with Daikin and the controller manufacturer, I now understand that a valve is only opened or closed when I want to increase the temperature or not.
With the Daikin system, I can set a target room temperature. According to Daikin, this target value does not represent the minimum temperature per room but rather the "preheating value," if I understand correctly. This value was previously set at 23°C (73°F).
In the bedroom, I set the digital controller so that heating only starts when the temperature drops below 18°C (64°F). Despite this setting, the room temperature has always been 22-23°C (72-73°F), although the digital controller shows that heating is off. After changing the target room temperature from 23 to 21°C (73 to 70°F), it got a bit cooler. However, in the bathroom, heating is supposed to activate below 23°C (73°F). The temperature there is 22°C (72°F), and the digital controller indicates that heating is active. Yet, the room does not get warmer, and the floor heating does not noticeably warm up either.
Conclusion: I still have not understood the logic behind the target room temperature setting. In our previous apartment, we also had underfloor heating with analog controllers that I could adjust higher or lower. That worked wonderfully, and I felt like I could control the temperature. Here, with the air-to-water heat pump, I don’t have that feeling. Also, the towel warmers do not get truly warm (only lukewarm), which Daikin says is normal even when the dial is set to 5. This is apparently because it is a low-temperature heat pump. Without the electric booster to warm the towel warmers, they are essentially ineffective. Is this normal? Could there be an error, or do I need to use completely different settings?
If anyone has experience with this topic, I would greatly appreciate your feedback. At the moment, I feel a bit lost on this subject.
_Ugeen_ schrieb:
Our technician told me that I should reduce the flow rate in the rooms where it should get cooler and increase the flow rate where it should get warmer. Well… something along those lines. Try searching for thermal balancing.
Whether you want to train as a heating expert is up to you, but it’s advisable to familiarize yourself with the basic principle.
The energy source has nothing to do with the issue that you can’t achieve large temperature differences between rooms in a new build.
There are a few things to be aware of when it comes to a new build or underfloor heating (usually, the better the insulation standard, the stronger the effect).
Temperature differences between rooms. Depending on the setup, you can achieve some difference. But since interior walls are usually not insulated and offer little resistance to heat, you effectively heat the adjacent room as well (or the one above or below). A classic example is a bathroom next to a bedroom. The bathroom is set to 24°C (75°F), the bedroom to 18°C (64°F). The bathroom doesn’t reach 24°C, while the bedroom is at 21°C (70°F). Flow rate is reduced in the bedroom and fully open in the bathroom.
Some may say this worked fine in their old house, but that’s likely because more heat was lost through exterior walls and windows, so this loss outweighed the heat gain through interior walls.
Thermal inertia. Underfloor heating is slow to respond, especially combined with good insulation and low supply water temperatures.
If a room feels too warm and you try to cool it down quickly by lowering the thermostat, you might only notice the change the next day. Why? Good insulation keeps the heat inside the room, and the heat stored in the screed persists for a long time.
So if you want one room to be cooler than another, yes, you should adjust the flow rates. But keep in mind that in a new build with underfloor heating, this is only possible to a limited extent.
Edit: This is by no means a complete explanation and is simplified. In detail, there are often additional factors at play.
Thank you again for all your advice. Last night, I read up on the topic and came across the following product. The Homematic IP underfloor heating actuator seems to handle everything automatically and eliminates the need for manual adjustments or hydraulic balancing. Does anyone here have experience with this or can assess whether it is useful?
A
Alessandro8 Oct 2021 08:26Do you have the lengths of the heating coils and the heat load for each room?
There are calculators and formulas available online that can help you estimate the (approximate) flow rates. This way, you can roughly check whether the Homeatic system is working correctly.
There are calculators and formulas available online that can help you estimate the (approximate) flow rates. This way, you can roughly check whether the Homeatic system is working correctly.
_Ugeen_ schrieb:
Thanks again for all your advice. Last night I read up a bit on the topic and came across the following product. The Homematic IP underfloor heating actuator seems to control everything automatically, or at least takes care of manual adjustments and the hydraulic balancing. Does anyone here know it or can judge whether it makes sense? I know the company; we had their wireless thermostats installed on the radiators in our old apartment. It worked pretty well.
I can’t judge exactly how the heating actuator works. I didn’t read it in detail, only saw something about stepless flow regulation. To achieve that, you’d either need actuators capable of that (which are rare) or the actuator controls it via something like pulse-width modulation. I’m not technically detailed enough to say.
The question is: do you really need it?
Usually, to control the system with Homematic, you need an access point. So you’d be spending another 300–400€ on devices, which also consume power and can break. Hydraulic balancing is not complicated. It takes about one winter’s time, but that’s it. If you do it properly, you shouldn’t have to adjust your room thermostats again.
In my case, KNX is installed. I integrated the actuators into the KNX system (for various reasons, not because I said I needed to). So, theoretically, I could program anything. For example, increase the living room temperature by 0.5 degrees Celsius (about 0.9°F) on the third full moon of the year if there are more than 4 hours of sun before 4 pm and wind speed from southwest is over 1.5 m/s (about 5.4 km/h or 3.4 mph), but only when someone is present.
And you know what I did? One winter season of hydraulic balancing. All actuators are always fully open; the rest regulates itself. Maybe I’ll fine-tune a bit this winter (the second season in the house). But so far, it’s been totally trouble-free. Now that it got colder, the heat pump started automatically, and just like that, the temperatures are within +/- 0.3 degrees Celsius (about 0.5°F), as I balanced last season.
Yes, there are a few nuances. When the sun shines strongly or it’s very windy, etc. But you can’t really regulate that because the system is too slow to respond.
As a layperson, I am always surprised that operating an air-to-water heat pump seems to require a degree (-:
If I had known this, I would have chosen gas instead. The extra 10 euros per month would have been worth it to me for the peace of mind and to simply be able to turn up the heat during the transition periods…. I am a woman, and it is almost unbearable that the heating doesn’t turn on because of some hysteresis issues or whatever (my husband’s words)… On the ground floor, I turn on the stove, and I’m freezing in the bathroom (-: Typical women….
If I had known this, I would have chosen gas instead. The extra 10 euros per month would have been worth it to me for the peace of mind and to simply be able to turn up the heat during the transition periods…. I am a woman, and it is almost unbearable that the heating doesn’t turn on because of some hysteresis issues or whatever (my husband’s words)… On the ground floor, I turn on the stove, and I’m freezing in the bathroom (-: Typical women….
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