Small Flows in Rotameters: New Underfloor Heating Installation, HALM HEP Plus 25-6.0 E 180 Pump

Hello
I have a problem with a newly launched installation
Problem:
1. small flows on rotameters on two (first floor, ground floor) manifolds. Despite setting the pump to the maximum "3" speed, the rotameters indicate a maximum of 2 l/min in the loops, and about 0.5 l/min in one on the first floor and two on the ground floor.
Facts:
1. I attach a photo of the installation and a very simplified and illustrative diagram.
2. The pumps are HALM HEP Plus 25-6.0 E 180. I attach documentation for the pump
3. About 700 m of floor heating is connected to the distributor on the first floor, the longest loop is about 90 m. The length of the fi 25 pipe from the manifold to the pump is about 9.5 m, including 3.5 vertically
4. About 600 m of floor heating is connected to the manifold on the ground floor, the longest loop is about 100 m. The length of the fi 25 pipe from the manifold to the pump is about 5 m, including 1.5 vertically
5. The system is vented - it has been venting for about a week
6. I do not know why, but the pumps currently consume about 25-27 W - which means that they do not work with maximum power (50 W), so why such low flows? In my opinion, the flows are too small for the 3rd gear - am I wrong? And if they are too small, where could the error be?
Question
1. On the upstairs manifold, the installer connected two loops from one room to one input and output on the manifold. He just gave tees in front of the manifolds. Is such a solution acceptable?

Thank you in advance for your help

Do you want to say that after the clutch, the entire supply and return installation is to go through fi 22? There is a topic on the electrode about selecting the cross-section of pipes. Spin everything you can, leave one loop as there will be more flow, you have the answer.

The problem then should be the designer and installer.
ad. 1 Part of the installation made of PVC pipes - are you sure they are unobstructed? With such long loops, a pump with a maximum lifting pressure of 4m is a bit small in my opinion. As long as the smallest flows are on the longest loops, you have the answer. A well-executed floor or other installation cannot vent for weeks.
ad. 1 the other Do you have any thermostatic valves at the ends of the loop or is it a constant flow system? Does this underfloor heating work at all? where are the departures from the loop connected?
ad. 6 The pump has electronic control depending on its load, specifically the inlet-outlet pressure difference. If you power all loops at once, there is a small pressure difference across the pump (assuming the system is vented) and the pump reduces its power due to the combined characteristics

The installer, as usual, thinks that everything is OK. But I have doubts and unfortunately I have no one to talk to about it.

- The supply and return is not through fi 22 it enters a larger cross-section and then to the clutch. I drew it on a new diagram - you can see it in the picture.

ad.1 I have no idea if they are unobstructed - how to check it? The pumps have a lift of 6m.

ad.1 I drew departures from the loop in the diagram. The manifolds are supposed to have actuators connected to thermostats, but there is nothing yet - they are unscrewed to the maximum flow. Rotameters are also turned on for maximum flow.

ad.6. And that's what I don't fully understand, the pump does not go to maximum and the flows are small on rotameters - then where is the problem? The system has low resistance but the pump capacity is too small?

Also, does your underfloor heating work at all? Try it as colleague @trance123 wrote

trance123 wrote:

Spin everything you can, leave one loop as there will be more flow, you have the answer.

Do this for each loop. You will see the differences and you will be able to draw some conclusions.

I did such a test - in this case on a single rotameter there was a minimum of 2 to 4 l / min. I did each loop like this and there were higher flows when only one loop was running.

Added after 13 [minutes]:

The second issue is what flows should be? - if the pump is set to maximum and each loop is open. Which flow indications say it's good and which say it's bad?

The flows should be such that the heating works. You wrote that in the case of powering one loop, the flows are larger. According to me, it means what I wrote in post #3. That is, with power to all loops, the pump finds less differential pressure between its inlet and outlet and then reduces power. Try to run only one loop, additionally choking it. The pump should increase power. Please tell me if this is the case. In general, these flows are not large because underfloor heating works in such a way that it should receive heat from the medium, i.e. lower its temperature to the temperature set on the return from the loop.

OKAY. I will do so. And another question:
1. On the upstairs manifold, the installer connected two loops from one room to one input and output on the manifold. He just gave tees in front of the manifolds. Is such a solution acceptable?

Is acceptable. As the loops are in one room, there will be no problem with temperature control. If it turns out that the returns of these loops have different temperatures, the warmer return will have to be throttled, e.g. with an additional valve. As long as the loops are of comparable length, this shouldn't be a problem.
If possible, try to replace each of the pumps with a regular one without this electronic regulation for some time (you have a typical 180 mm pump and another one will fit) and you will see the difference and you will see how the electronic regulation affects the operation of the system. You don't have to buy a pump because your installer definitely has one.

Hello and welcome. I have the same problem as my friend. But I will phrase the question differently. What should I do to make the rotameters open? Should the pump be more powerful? At the moment, the pump serves 6 loops on the ground floor and 4 on the first floor. Rotameters, although they are manually opened / unscrewed, practically do not indicate flow. Hot water flows to the manifold without any problems and it seems to me that it gets into the installation. When choking everyone on the ground floor in turn, 2 of them open basically properly. I also have electric controllers, which, due to the fact that the rotameters do not work, have lost their function. So the question. Should I change the pump to a more efficient one? At the moment there is also a Wilo Yonos with a lift of probably 5 m. I would be very grateful for a hint. Regards.