Optimal Control Methods for Underfloor Heating: Comparing Two Options for 240 sq m House

I have underfloor heating in the house, floor and ground floor, a total of approx. 240 sq m. The heating is separated so that each room has a separate circuit (loop) fastened to the manifold (one for each floor). There is no automation on the manifolds (only valves). There is a single-function condensing oven with a weather sensor and a smart controller, but placed on the stove so far (fresh thing, the stove started on Saturday).

I have two options to play the topic of heating control.

Option 1

The furnace control remains on the furnace. The furnace will control the temperature of the heating water based on the outside temperature (from the sensor) using the temperature set on the furnace but also according to the heating curve set there instead of reading the real temperature in the rooms. In the rooms there will be thermostats that will control the valves on the manifolds, if necessary, opening or throttling the flow of water in a given circuit (loop).

Option 2

The furnace controller is moved from the boiler room to the hall below, or a second one at the top. The furnace controls the water temperature based on the measurement of the real interior temperature, thus correcting the heating curve (and probably somehow taking into account the outside temperature). We do not install thermostats or actuators in manifolds, we set them manually on manifolds or throttling in some rooms so as to obtain an appropriate temperature distribution.

Which of these options is better?

Specialists in underfloor heating (those who made them) say that option 1 should be used. However, I think that option 2 may be much better, more sensible - because there is a chance for less gas consumption, especially since the house is b. solidly thermally insulated.

Exactly the same topic I am processing and I read with pleasure the local answers.

Buddy attic and ground floor have a completely different accumulation and inertia, so forget about one regulator and the advice of "specialists". Neither one or the other method will give satisfactory results.
Separation of upper and lower circuits by solenoid valves is required, min. two temperature regulators and only at a given level do we regulate flows.
Weather control may (but not be necessary) be and simply raise the temperature of the heating medium depending on the outdoor temperature.
I am still installing a controller in the bathroom / bathrooms, which works independently of the main ones from above and below, hydraulically the bathroom circuits are connected in front of the solenoid valves from above and below.

andrzej lukaszewicz wrote:

Buddy attic and ground floor have a completely different accumulation and inertia, so forget about one regulator and the advice of "specialists". Neither one or the other method will give satisfactory results.

Thanks for the detailed reply. After analyzing, however, it seems to me that what you say is practically "option 1". In option 1, there are to be thermostats in each room controlling the manifold for a given floor individually with an actuator that regulates the flow in the loop for that room. It would coincide with what you write in your entry only "even more", i.e. the controller not per floor but for each room.

My fears about this approach are this: in such a system the stove can work without sense heating the water even when all the loops in the rooms will be cut off by their valves, because in all rooms the set temperature will already be reached. Of course, then very warm water would return to the furnace but I don't know if the furnaces have return water temperature sensors and react to it.

The furnaces have a temperature sensor, if it reaches the set temperature on it, it turns off, the boiler turns off the faster the fewer circuits require heating. In fact, however, some "empty" attachments will occur.
The correct minimum solution is two regulators (for the floor I recommend Euroster 2026 or Euroster Q7 - both have a very good algorithm to counteract temperature fluctuations caused by floor inertia - tested in real conditions), one below and one above. For this T6 or T6RX strip (wireless) and electrothermal actuators (EurosterT1NC or any other NC) for manifolds. The T6 strip is connected to regulators which, through the strip, give a signal to turn on the furnace and switch on the appropriate circuits, the strip can also control the floor pump. When all controllers reach the right temperature, the servomotors are closed and the boiler and pump are switched off in the correct order.
The full option is a regulator in each of the rooms, however, there should be no major problems when two or even three rooms of similar volume will be regulated by one regulator located only in one of these rooms, then two loops or control can be connected to the terminal for one output two inputs on T6 with one controller then you can connect and four separate loops (rooms).
In the system with the T6 strip, I recommend using two controllers at the beginning, then if necessary, you can always add the appropriate number (max. 6 regulators per strip).

In your case, solution No. 1 gives the highest comfort of using the rooms, especially if you would like to maintain different temperatures at different times of the day in different rooms. Individual thermostats in these rooms give the possibility of such control without continuous gouging in the manifold with flows in op loops. It should be remembered that the underfloor has a very high inertia (i.e. it heats up long and gives off heat for a long time before it gives the effect of changing the temperature of the room) and this must be tested and errors should be included in the heating schedule for each of the thermostats separately, or the purchase of such a system with thermostats that "learn" each room separately and operate well in advance.
You will probably have the right control bar for each distributor. Choose the one that has the contact switching off the pump or heat source (boiler) when there is no heating demand. Connect them in series and only if both distributors do not need to heat, the boiler will turn off.

And how is your hydraulic system built: boiler + 2 floor distributors? Directly the entire floor goes from the boiler, is it separated by a hydraulic clutch and additional pumps?

Euroster Serwis wrote:

The furnaces have a temperature sensor, if it reaches the set temperature on it, it turns off, the boiler turns off the faster the fewer circuits require heating. In fact, however, some "empty" attachments will occur.

OK, i.e. it is a correct and effective solution from the comfort side, but it can give increased wear.

Euroster Serwis wrote:

The correct minimum solution is two regulators (for the floor I recommend Euroster 2026 or Euroster Q7 ...

The problem is that I'm not at the design stage - the floor is already made (as I wrote above - a separate loop for each room), heating started at least on all open circuits for now. There are cables for thermostats in the rooms (they go to the manifolds from them) but there are no cables for the furnace regulators. The moment is now plaster, so putting them although possible already requires forging plaster on a fairly large section, because the boiler room is at the very end / corner of the house, away from the rooms. That is why I wonder how much it is worth playing with.

ls_77 wrote:

the purchase of such a system with thermostats that "learn" each room separately and operate well in advance

This is something from PURMO. But all in all I should explore the topic of what thermostats will be.

ls_77 wrote:

You will probably have the right control bar for each distributor. Choose the one that has the contact switching off the pump or heat source (boiler) when there is no heating demand. Connect them in series and only if both distributors do not need to heat, the boiler will turn off.

The problem is that I don't have cables pulled into the boiler room from the distributors.

ls_77 wrote:

And how is your hydraulic system built: boiler + 2 floor distributors? Directly the entire floor goes from the boiler, is it separated by a hydraulic clutch and additional pumps?

Exactly. There are no clutches or pumps, including because there are no other things in the house - radiators operating at a different temperature.

If you do not have wires between the distributors and the boiler room, then there will be a problem with turning off the boiler as all op circuits close. Maybe there are some wireless transmitters?

I do not know the Purmo system, but you can also use the DanfossLink system - all wireless components (room thermostats, control strips for manifolds and boiler relay). The system "ears" the rooms and additionally controls the heating circuits (loops) op with the PVM signal, i.e. not on / off, but the time-modulated opening signal depending on the heating demand.

ls_77 wrote:

If you do not have wires between the distributors and the boiler room, then there will be a problem with turning off the boiler as all op circuits close.

Well just no. The gentlemen's installers concept was that the stove simply heats the water (!). And that's why I started to think about moving the boiler regulator from the boiler to the interior of the house, because then the stove will turn off as the set temperature will be. I'm not sure if it's the Vaillant control that can handle the inertia of the floor. From what I've learned so far it won't change - I just have to choose the heating parameters (curve, temperatures) so that the stove does not turn on too much without the need. If the furnace has a return water temperature sensor, it should not heat it without sense if it will be basically the same temperature as the outgoing (and so it will be in a hypothetical situation when all circuits close).

I avoid radios as much as I can, I want to reduce RFI (radio interference) to a minimum.

Added after 9 [hours] 46 [minutes]:

[Heh ... I just found out that gentlemen installers connected one of the distributors upside down - i.e. hot water is fed into the blue circuit, the one with valves, and cold is taken from the red, the one with such transparent dynks.]

Maybe I did not express myself precisely - I meant to automatically turn off the boiler, as each of the op strips will not have heat demand. Of course, the boiler will turn itself off - it simply will not be able to maintain the set flow temperature and turn off the burner. However, it is more about the fact that when all the circuits are closed, the pump in the boiler will push into the "closed" system. The fact that the boiler has a built-in bypass valve that will open so that the pump does not run dry, but it would be best for the boiler pump to turn off immediately.

Moving the Vaillant controller to the room will do nothing. Ie. you can set the operation and the influence of room temperature on the "Thermostat" or "Correction" on the controller, but you will only have to measure this temperature in one place. If you find the location of this room temperature sensor that it roughly corresponds to the average temperature in the entire building, you can use it there, but you have to take into account the possibility of other temperatures in other rooms. If you want to precisely regulate the temperature in each room and at different times of the day, then you must use the floor control (thermostats in each room and control strips at the manifolds).

OK, that is, I sensed the problem well (pushing senselessly into a "closed" system, which can easily happen with good thermal insulation), but I wanted to solve it badly by moving the regulator from the furnace. Unfortunately, the problem is that I do not have any cables pulled from the op splitters (where, as I understand, these strips will be added) to the boiler room, so it will not be enough to convey this signal from the strip. So my "floor specialists" didn't seem to foresee such a thing.

As a side note, since I am talking to a specialist without quotation marks: what are the potential consequences of feeding "the other way round" or feeding hot water from the boiler to the bottom, "blue" strip instead of the top, "red"?

Flow meters may not show flow or will not open at all. In them, the water is to flow from above, then with appropriate pressure press on the mushroom and this entails a flow indicator.
On the bottom beam, the inflow to the stop valve head can cause a rattling because here the water inflow should be from below.
It's best to swap the beams themselves if you don't want to rework the pipes. Only on the upper beam there must be space for the thermal actuators to fit, and you will have little space there when you swap the beams. Rather, for the sake of peace, redo as it should be.

It depends on what rotameters - if zero is at the top of the scale, then rotameters for mounting on the supply beam, if zero on the bottom is on the return beam. It cannot be ruled out that it is mounted correctly. Check

The distributor photos show that the power supply is the upper beam with rotameters (red dot) and the return is the lower beam (blue dot). Well, but for sure you can check the rotameters.

Such control should look in such a way that a given temperature controller from a room or the whole level (simplified version) opens a given circuit (or the entire beam - up or down) using a servomotor and at the same time the boiler starts. If the control will be individual for each room, we leave some circuits without an actuator, e.g. hall, bathroom, and there will be no problem with closed circuits for the time the thermal actuator is activated.
As for rotameters: at the moment they work as you turn on the boiler? if so, then the power directions are fine.
You write that you don't have any wiring, what are those wires in the picture?

ls_77 wrote:

The distributor photos show that the power supply is the upper beam with rotameters (red dot) and the return is the lower beam (blue dot). Well, but for sure you can check the rotameters.

It was supposed to be like that, but after turning on the heating, it turned out that the lower beam did not heat up, from which I conclude that this is where the entrance is and return from the upper, which is the opposite of how it was supposed to be. Let's add that the ground floor is the opposite, that is correct, and the rotameters are completely different and I do not know how to read them.

Added after 1 [hours] 49 [minutes]:

andrzej lukaszewicz wrote:

As for rotameters: at the moment they work as you turn on the boiler? if so, then the power directions are fine.

It's hard for me to say this because I see the rotameter for the first time nevertheless they are empty i.e. steamy but not full of water. They look different from the ones I have on the splitter at the bottom, but those are also a different model (they do not have such covers).

andrzej lukaszewicz wrote:

You write that you don't have any wiring, what are those wires in the picture?

These wires are distributed to rooms on the first floor, they are to supply the signal from the thermostats in each of them.

I have the same situation as the author of the topic, did you find a solution?
Currently, I only use the weather and I want it to be warmer in the bathroom, I wonder if it makes sense to load all the automation.
I would not like to connect the controller from the strip to the stove because I do not see the point in turning the stove on every moment as one of the loops changes the temperature, I prefer to be controlled by the weather.