Hello,
we are currently struggling with our heating system. It is warm everywhere in the house—both on the ground floor and in the heated basement room—around 21-22°C (70-72°F). However, the temperature in all rooms in the attic is noticeably lower, usually about 2°C (3.6°F) difference. This is problematic because a) it is too cold and b) it also affects the bathroom.
We have already tried various measures. We adjusted the heating curve, the manufacturer’s service performed a firmware update, and the hydraulic balancing was done again... but the problem remains the same. The attic stays consistently about 2°C (3.6°F) cooler than the other floors. The heating technician said this is normal because of the many windows and that it always tends to be cooler in the attic. He advised us to simply increase the supply water temperature. But that can’t be the solution, right? Although this raises the temperature in the attic, we then have to lower the temperature on the ground floor because otherwise it becomes too hot. The 2°C (3.6°F) difference always stays the same. We have solid ceilings and walls, underfloor heating everywhere, and the room thermostats turned up fully.
Is this really normal, or is the heating technician just trying to sell us that because he has no other ideas? What is your experience? Do you also have such temperature differences?
we are currently struggling with our heating system. It is warm everywhere in the house—both on the ground floor and in the heated basement room—around 21-22°C (70-72°F). However, the temperature in all rooms in the attic is noticeably lower, usually about 2°C (3.6°F) difference. This is problematic because a) it is too cold and b) it also affects the bathroom.
We have already tried various measures. We adjusted the heating curve, the manufacturer’s service performed a firmware update, and the hydraulic balancing was done again... but the problem remains the same. The attic stays consistently about 2°C (3.6°F) cooler than the other floors. The heating technician said this is normal because of the many windows and that it always tends to be cooler in the attic. He advised us to simply increase the supply water temperature. But that can’t be the solution, right? Although this raises the temperature in the attic, we then have to lower the temperature on the ground floor because otherwise it becomes too hot. The 2°C (3.6°F) difference always stays the same. We have solid ceilings and walls, underfloor heating everywhere, and the room thermostats turned up fully.
Is this really normal, or is the heating technician just trying to sell us that because he has no other ideas? What is your experience? Do you also have such temperature differences?
K
Knallkörper8 Mar 2017 08:18Musketier schrieb:
Our heating technician also pointed out that the pump must be set to a certain minimum capacity to achieve the flow height to the upper floor. When adjusting the output on our pump, a brief display in meters also appears.Hello Musketier,
that is not correct either. As mentioned, the flow height does not matter in a closed circuit. For pumps, it is standard practice that the stated differential pressure is always given in meters, essentially as the flow height. If a cooling circuit has a 2 bar pressure loss (flow losses), a pump with at least 20 m (65 feet) of "flow height" is selected. Even in plant engineering, the mistake is sometimes made to additionally consider the actual flow height. It becomes critical when the pump is installed "upstairs" and the "flow height" is deducted.
That’s quite possible. I’m not very knowledgeable in this area. I could probably test it fairly easily by lowering the pump output further and observing the temperature changes on the upper floor.
I have had my heating system adjusted for about a year now, so that except for the guest room and bedroom, no electric radiators are in use, and yet the desired temperatures are maintained in the rooms both in summer and winter.
During the heating system maintenance, the technician was initially a bit surprised when I told him that I had changed the flow rates and thus “disrupted” the hydraulic balancing. However, he was more than satisfied with the low supply temperature in return.
I have had my heating system adjusted for about a year now, so that except for the guest room and bedroom, no electric radiators are in use, and yet the desired temperatures are maintained in the rooms both in summer and winter.
During the heating system maintenance, the technician was initially a bit surprised when I told him that I had changed the flow rates and thus “disrupted” the hydraulic balancing. However, he was more than satisfied with the low supply temperature in return.
Peanuts74 schrieb:
If we fully open all the thermostatic valves, there is also a temperature difference between the ground floor and the attic. It makes sense to me because the attic still has the roof acting as an "external wall." Additionally, the water in the supply line may cool down slightly on the longer route from the basement to the attic, even with insulation.How big is this difference? Okay, that could also be the case with us... the pipes are not insulated yet....
K
Knallkörper8 Mar 2017 20:14Nafetsm schrieb:
How big is this difference? Well, that could also be the issue for us... the pipes are not insulated yet...You could measure the temperature difference between the start and the end. I would estimate it to be at most 0.1 Kelvin. Of course, your upper floor (first floor) will then be noticeably 0.05 Kelvin cooler. Didn’t you have physics classes?
markus2703 schrieb:
That’s exactly what I already said. It’s just logical, and besides, only a 1-degree difference...
Increase the flow temperature until the upper floor is comfortable, and then adjust downwards accordingly. Problem solved.It’s not a 1-degree difference (that wouldn’t worry me), but more like a solid 2 degrees.
The flow temperature is set to a maximum of 35 degrees Celsius (95°F) at an outside temperature of -20 degrees Celsius (-4°F). Of course, I can adjust that... but again, changing it doesn’t affect the 2-degree difference to the upper floor. It gets warmer (3 degrees more flow temperature = 0.3 to 0.5 degrees Celsius (0.5 to 1°F) room temperature), but the difference remains.
The flow rate on the upper floor is fully opened on all valves. Just checked. The pump should be powerful enough. It ran at maximum power (level 6) in the previous weeks, now it’s set to level 1. No noticeable impact on the temperature so far.
The manufacturer’s service technician suggested that the heating system might need bleeding or flushing, because air bubbles could be trapped in the pipes after installation. However, the installer refuses to do this and claims it’s impossible, since otherwise there wouldn’t be any flow at all on the ground floor.
We haven’t received any documents from the general contractor or the heating specialist regarding the layout of the underfloor heating. We do have the hydraulic balancing paperwork, though. But I can’t say what the layout plan for the heating loops looks like. Should we be getting that? The loops were installed very tightly... surprisingly, where they were laid less densely (e.g. hallway), it’s also nicely warm. That’s actually where we had concerns, but not in places with tight loop spacing like the bathroom...
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