ᐅ Underfloor Heating on the Upper Floor – One Room Always Stays Too Cold
Created on: 13 Nov 2024 23:19
A
Allthewayup
Hello everyone!
I'm at my wit’s end. I just can’t get the children's room above 20.5 degrees Celsius (69°F), while all the other rooms on the upper floor reach between 21.5 and 22.0 degrees (71.5 and 72°F) with the same settings. The affected room also feels noticeably cooler.
I have slightly increased the flow rate, but with no success (+0.3 degrees). The valve is now 95% open but the room temperature remains unchanged.
Thermal imaging camera showed nothing unusual, no cold spots. I checked all window seals, also fine. Photos from the installation of the underfloor heating were reviewed, no issues visible. The hydraulic balancing has been done twice to rule out errors.
Two heating circuits of identical length run through the 17 sqm (183 sqft) room. Pipe spacing is 10 cm (4 inches). The supply temperature at 5 degrees Celsius (41°F) outdoor is 27 degrees (81°F). The heating curve is set at 0.35, so at 0 degrees (32°F) outside, the supply temperature is about 28.3 degrees (83°F). We have 22.2 degrees (72°F) on the ground floor, so the supply temperature cannot be the problem.
I turned off the mechanical ventilation for 24 hours, no change. Removed the carpet for 24 hours, no change. There is only a small wardrobe on the floor; the bed is a loft bed and does not affect the underfloor heating.
I don’t understand why this room stays noticeably cooler than the adjacent room (exactly the same conditions).
Do you have any ideas where the problem might be? I don’t want to raise the supply temperature for the 17 sqm if there is no reason to do so for the other 140 sqm.
I'm at my wit’s end. I just can’t get the children's room above 20.5 degrees Celsius (69°F), while all the other rooms on the upper floor reach between 21.5 and 22.0 degrees (71.5 and 72°F) with the same settings. The affected room also feels noticeably cooler.
I have slightly increased the flow rate, but with no success (+0.3 degrees). The valve is now 95% open but the room temperature remains unchanged.
Thermal imaging camera showed nothing unusual, no cold spots. I checked all window seals, also fine. Photos from the installation of the underfloor heating were reviewed, no issues visible. The hydraulic balancing has been done twice to rule out errors.
Two heating circuits of identical length run through the 17 sqm (183 sqft) room. Pipe spacing is 10 cm (4 inches). The supply temperature at 5 degrees Celsius (41°F) outdoor is 27 degrees (81°F). The heating curve is set at 0.35, so at 0 degrees (32°F) outside, the supply temperature is about 28.3 degrees (83°F). We have 22.2 degrees (72°F) on the ground floor, so the supply temperature cannot be the problem.
I turned off the mechanical ventilation for 24 hours, no change. Removed the carpet for 24 hours, no change. There is only a small wardrobe on the floor; the bed is a loft bed and does not affect the underfloor heating.
I don’t understand why this room stays noticeably cooler than the adjacent room (exactly the same conditions).
Do you have any ideas where the problem might be? I don’t want to raise the supply temperature for the 17 sqm if there is no reason to do so for the other 140 sqm.
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Allthewayup14 Nov 2024 11:38yellow = Office (10m² (108 sq ft)) TARGET = 20, ACTUAL = 22.2
green = Bedroom (17m² (183 sq ft)) TARGET = 21.5, ACTUAL = 21.5
red = Child 1 (17m² (183 sq ft)) TARGET = 21.5, ACTUAL = 19.9!
purple = Child 2 (12m² (129 sq ft)) TARGET = 21.5, ACTUAL = 21.5
blue = Bathroom (12m² (129 sq ft)) TARGET = 22, ACTUAL = 21.9
Thermal balancing was done 2 weeks ago by a heating technician friend. Since there was no result, it was reset to factory settings.
I also don’t understand why heating circuit 2 in the bedroom is mostly off, and only heating circuit 1 is running.
The KNX system also shows that the actuator motor for the office is closed, although the heating manifold motor is open.
*Edit
The heating pump is running at full power (40W).
R
RotorMotor14 Nov 2024 12:20I became a bit concerned when you mentioned KNX.
Are you sure it doesn’t turn off at times?
Night setback or something like that?
And especially, how are you measuring the temperatures?
With my KNX sensors, the deviations were quite high.
Try comparing that with an external thermometer.
And please check that the flow indicator isn’t just stuck.
Are you sure it doesn’t turn off at times?
Night setback or something like that?
And especially, how are you measuring the temperatures?
With my KNX sensors, the deviations were quite high.
Try comparing that with an external thermometer.
And please check that the flow indicator isn’t just stuck.
B
Benutzer 100114 Nov 2024 12:30Note the green taco setters. One open, one closed? They should receive the signal from a thermostat and always operate together. What’s the point of having two heating circuits in one room if one compensates for the other?
Regarding the children's room: if all wiring is correct—“as I can see for the bedroom, someone has made a mistake”—under-supply of the flow can occur if the heating pumps are undersized. So please set all actuators to permanent open or remove them and perform the hydraulic balancing again.
Regarding the children's room: if all wiring is correct—“as I can see for the bedroom, someone has made a mistake”—under-supply of the flow can occur if the heating pumps are undersized. So please set all actuators to permanent open or remove them and perform the hydraulic balancing again.
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Allthewayup14 Nov 2024 12:31RotorMotor schrieb:
I became a bit concerned when you mentioned KNX.
Are you sure it doesn’t occasionally turn off?
Night setback or something similar?
And especially, how are you measuring the temperatures?
With my KNX sensors, the deviations were quite large.
Compare that with an external thermometer.
And please check that the flow indicator isn’t simply stuck. No, they remain open continuously. I was at the heating circuit distributor about 20 times within 3 hours and it was always open. I also manually set it to “open” for two days straight to prevent it from closing.
The temperatures are measured by the SMT glass switches mounted at a height of 1.5m (5 feet) in the rooms. A comparison with an external thermometer showed no significant deviations (<0.5°C (0.9°F)).
A
Allthewayup14 Nov 2024 12:36Offtopic schrieb:
Notice the green taco valves. One open, one closed? They should receive the signal from a thermometer and always operate together. What’s the point of having two heating circuits in one room if the other compensates for it? Yes, I already mentioned that. It doesn’t make sense to me. I’ve assigned the electrician to check it.
However, the initial issue was not about green but about red. Continuous flow but still only about 20°C (68°F).
All actuators were manually set to open for days; temperatures are rising everywhere except in the red circuit line.
I will now bring this to our expert’s attention and add it to the list of defects. I’m really getting annoyed by this. My time isn’t unlimited either.
*Edit:*
The heating technician can currently excuse himself by saying that the planning was based on standard temperatures and I’m not following them.
Obviously, with 35°C (95°F) supply temperature, I throttle 22 out of 23 heating circuits. Well done.
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RotorMotor14 Nov 2024 13:03Allthewayup schrieb:
No, they stay open continuously. I checked the heating circuit distributor about 20 times over 3 hours, and it was always open, or I manually set it to “open” for two days so they wouldn’t close. And if you close them via KNX, does the flow indicator change (to zero)? Or does it stay there?
Allthewayup schrieb:
The temperatures are measured by the SMT glass switches in the rooms, which are mounted at 1.5m (5 feet) height. A comparison with an external thermometer showed no significant deviations (<0.5 degrees Celsius (0.9°F)). I assume you mean MDT, not SMT?
I have installed that exact gauge myself.
Some of them need a 1-degree correction!
So measure again with an accurate thermometer.
Allthewayup schrieb:
I will bring this up with our heating engineer and add it to the defect list. I’m slowly getting really annoyed. My time isn’t unlimited either.
*Edit:
The heating engineer can currently excuse himself because the design was based on standard temperatures, which I’m not running.
Sure, at 35°C (95°F) flow temperature I throttle 22 of 23 heating circuits. Well done... You won’t have any chance with an expert if you don’t raise the flow temperature and demonstrate that it still doesn’t get warm...
Basically, I feel like you’re looking for a single, all-encompassing solution here.
But a hydraulic balancing is a laborious process that takes several weeks.
So proceed as follows:
- Calibrate all thermometers or use accurate external ones
- Make sure the Taco setters display correctly
- Disconnect the KNX control or set all actuators permanently to open
- Then start throttling the room that is too warm
- Continue this until the temperatures are balanced everywhere.
It is already noticeable that the smaller purple room has more flow than the significantly larger red room.
That can’t be right.