Hi Tamas!
My respect to your installation company about how they insulated the pipes in the heat circuit distributor - I hope this is the right term.
Yes, this (dumb) smart controls are exactly the problem, because they completely disrupt the synchronous storing of the positive/negative energy into the floor. So what is the problem here?
A low temperature heat pump comes with one main restrictions compared to a gas or oil heating, it is not supposed to provide the dynamic temperature adjustments of oil and gas heating systems to allow overheating the floor of a single room in a short time that allows individual heat control, however modern insulated houses provide this anyway.
Instead a heat pump is supposed to provide a continuous energy flow over a long time keeping the building at a nearly constant temperature. As a consequence, the smart controls are a disturbance because they are often programmed to prematurely interrupt the energy flow instead of allowing the heat pump to provide the whether controlled target temperature of the house.
So usually the problem is, that the temperature curve and the heat pump output is set to be too aggressive, and would heat the building to a level that is actually not wanted. If your hydraulics is setup correctly, the approach is to remove all smart controls or to set them to a level at which they are always open (≥30°C room temperature). Than you reduce the temperature curve of the heat pump to a level, where the house and most rooms are reaching the expected/planned room temperatures.
In best case most rooms are reaching the same planned optimal temperature at the same time. If this happens, you can put the controls back on and set them to the planned temperature or a slightly above level. If some room is deviating from the planned temperature, you begin to slightly adjust the energy flow of the deviating rooms through the flow meters. Circuit of too cold rooms get slightly opened, while circuits of too warm rooms get slightly closed. Than you wait for some time until all rooms have adjusted to the changed settings and repeat the process trying to reduce the temperature curve further.
One thing to have in mind is, that by changing on flow, all flows in the heating system will adjust, since your secondary pump will try to deliver the same flow as before. So reducing one flow meter will lead to a slight raise in all others and thus increase the temperature, while increasing will lead to reduced temperature in all others - so you are just redistributing the energy. So if the overall energy in the system is to much you need to further reduce the temperature curve and finally you can fine tune by slightly adjusting the secondary pump.
The goal of the procedure is to make most rooms running on optimal temperature without any control. You need to achieve this for 50 to 70% of your rooms to finally stabilize the heat intake of your floor heating from your heat pump. If you reach this level, you will have very long synchronous phases, where the floor heating stores the energy in all rooms, with similar long phases in between, where the secondary pump is just slowly redistributing small amounts of energy between the room.
To complement this change you usually want to switch the sensor control of the heat pump from the out-sensor to the in-sensor and reduce the hysteresis between start and stop to a small a mount of just 2K. This makes sure that the room temperature is changing less within the cycles and prevent your rooms better from overheating through sunshine, since the in-sensor is measuring the solar gains thereby and adjusts the output of the heat pump quicker to the reduced consumption.
At the same time this change secures the heat pump against micro cycles where the temperature strucks the limit on the out-sensor through the initial high energy flow during the heat pump startup. You can imagine that the curve on the in-sensor is much flattened and that the heat peak usually needs 10 to 20 minutes to reach the in-sensor.
But be aware, you need to do the fine-tuning in the heating seasons with outside temperatures of around 0°C and repeat adjusting the temperature curve with outside temperatures of 5°C and -5°C so that the curve works equally well on the whole range without the circuit controls taking over.
May be your installation company can assist you in this process and also explain this better, but the temperature fine tuning usually has to be done by the residents. The general principle behind this is best explained in German by the Flow 30 Principle and the process is described as Temperature-based (Hydraulic) Balancing.
Best regards
Gwyn
