ᐅ New Construction – Uneven Underfloor Heating (Vaillant Aurocompact)

Hello,

I had the same problem once in a rental apartment where each unit had its own boiler and manifold. Our indoor temperature was constantly around 21°C (70°F), which was perfectly fine for us. Trying to make it warmer on very cold days didn’t work either. I adjusted the thermostats, changed the flow temperature, and so on... Since it was a rental, no one really cared how the heating was set up. As long as there were no complaints and everyone paid their utility costs. In hindsight, the utility bills were quite high because nobody had properly adjusted the heating system.

But since this is your own house, if I were you, I would have a heating engineer come and calculate the flow temperatures based on room size, check if the heating circuits are correctly connected to the manifold, and I would also ask for some guidance on how to adjust the temperatures yourself without risking excessive energy consumption or too high flow temperatures (which can damage the system).

The room temperature actually feels almost equally warm in all rooms according to our perception, but the floor temperature differs significantly, though consistently within the same rooms.

borderpuschl schrieb:

In the picture of the heating circuit manifold, you can see that all flow indicators are at the very top, meaning no flow.
Maybe the photo was taken exactly at the moment when all valves were closed, or there might be an error here as well. Possibly the control valves NC and NO are mixed up.

The photo was taken yesterday around 6 p.m. Nothing was changed, readjusted, or altered beforehand. I only opened the protective cover to photograph the heating manifold.
The flow indicators are the ones with the red caps, right? What would I need to adjust?

PS: Thanks for all the replies, which I find very helpful!

It’s good that all rooms are warm enough for you; that means the basics are covered.

Now you can check whether the system is running efficiently.

I assume the bathrooms have the warmest floors?

To start with, we need the following information from you:
- What heating load was calculated for the house.
- How many heating circuits do you have (the number of connections in the heating circuit manifolds).
- What flow rates do the parts with the red caps show when the heating is running.
- How long are the individual circuits.
- What supply and return temperatures do you have when the heating is running.
- What measured temperatures do you have in the rooms.
- Are all the thermostatic radiator valves (TRVs) in the rooms turned on, or are some switched off or set to zero.

It is quite normal for floors to have different temperatures.

Hello,

I have checked the documents to provide more data for evaluation. A hydraulic balancing was carried out, I quote:

“Expansion vessel checked: yes, fill pressure 1.5 bar



Calculation of heating circuit settings (underfloor heating):

Design supply temperature: 43°C (109°F)

Heating circuit return temperature: 32.4°C (90°F)

Determined total flow rate: 7.08 l/h (0.02 gal/h)

Total heating load: 6983 watts

Underfloor heating output: 6977 watts

Total water volume: 708.2 kg/h (1562 lbs/h)

Maximum pressure loss: 17200 Pa

Total underfloor heating surface area: 122.3 m2 (1317 ft2)

Total room area: 132.8 m2 (1429 ft2)

Pump head (at total flow rate): 1.06 m (3.5 ft)

Flow controller/branch control valve (single-pipe heating): present



TKM surface heating system according to DIN EN 1264, design:

Manifold 1: Tackersystem cement screed over pipe: 45 mm (1.8 inches), 1.2 W/mK

Hallway, kitchen, living room, WC, utility room, guest room => all on the ground floor

7 heating circuits, water volume 337.6 kg/h (744 lbs/h), PE-RT heating pipe 17x2



Manifold 2: Tracker system

Corridor (supply lines), bedroom, children’s room 1, children’s room 2, bathroom

4 heating circuits, water volume 370.7 kg/h (817 lbs/h)



Energy performance certificate:

Final energy demand: 52.5 kWh/m2*a

Primary energy demand: 58 kWh/m2*a

Overall compliance with the Renewable Energy Heat Act: 130% fulfillment rate



System evaluation according to DIN 4701-10

-Heating: Central heat generation, condensing combination boiler 15 kW, natural gas E, boiler efficiency at full load: 98%, Vaillant VSC S/D 146/4-5 190; two flat solar collectors for domestic hot water preparation

Distribution: Design temperatures: 35/28°C (95/82°F)

Individual room control with two-point controller 0.5 K switching differential

No circulation pump present

Heat demand: 7165 kWh/a (Primary energy: 7371 kWh/a)


-Domestic hot water: Central domestic hot water preparation, 2 heat generators (heat generator 1 covers 68% share solar system Sonnen-Energie Vaillant auroTHERM VFK 145 V; heat generator 2 covers 32% share hot water generation via the heating system)

Storage: Bivalent solar storage tank 270 l (71 gallons)"


These are all the data I could find in the building folder.


The ERR (which occasionally make a “clicking” noise) will be set to “6” (maximum) in all rooms around Monday, because we expect very warm weather in Brandenburg in the coming days.


The temperature measurements in the individual rooms will also be taken in the next few days.

The information is somewhat contradictory. While the energy performance certificate specifies design temperatures of 35/28°C (95/82°F), the heating circuit settings show 43/32°C (109/90°F).

Why do you want to set the ERR to 6 when it is getting warmer?

At the moment, there is not much you can do regarding the hydraulic balancing because it is already too warm and there are excessive solar gains.

Please also record the flow temperature at the gas boiler during operation.