Poor Flow in Underfloor Heating System: Causes in New Construction with Air-Water Pump, 250m2 Area

marcel_76 wrote:

saskia wrote:

marcel_76 wrote:

I removed the thermostatic valve and the flow with 3 manifolds turned on is in the range of 1-1.3. When closing the lower distributor, the upper one is in the range of 1.5-1.7 and it will not perform any more. But that's definitely better than below 0.6 before disassembling the valve. How do you think to buy a second wilo pico 25 / 1-6 and divide the ground floor from the attic into two pumps or the entire installation of wilo stratos 25 / 1-8 as suggested by one of your colleagues?

You already have all the information, the decision is up to you.

I will wait a bit, I will see how it heats up, i.e. whether the floor heats up faster and more equally and I think that I will enter two circuits so as not to heat the bottom of the house if it is not necessary and vice versa.
I think that you could buy a stratos 25 / 1-6 for the top power supply because it is probably more efficient than five 25 / 1-6

The basic saving with the floor heating is to reverse the temperature system of the room "upside down", namely the heat, against gravity, remains at the bottom in the zone where the household members are. This is unhealthy in some situations, but saves you money on heating.
With a floor heating, with warmer near the floor and colder under the ceiling, we need, for example, 18-19 ° C at a height of 1.5-1.8m, having the same thermal comfort as with radiators and 20-21 ° C. This is the main saving. If you still think that keeping the temperature at 20-21 ° C, despite the floor heating, you will use less energy, you are wrong, because 20-21 ° C for the floor heating is the same as 22-23 ° C for the radiators.
There is no need to veer the system to max. because we have savings anyway and it's warmer at home.
If your house has such and no other heat dissipation (insulation), then you will not exceed the energy demand in any way. neither the PC nor the fireplace will give you anything but extra costs. Lowering the operating temperature of the system means extending the operation time of pumps and controllers, and at some point further feeding of the system brings unnecessary losses instead of benefits.
Separation of the circuits makes it easier to control room temperatures, i.e. the ground floor can only have 18 ° C at night and the floor (bedrooms) e.g. 20 ° C, and in the morning the temperature will start to change the other way around, i.e. around 7 a.m. will be identical (using both floors, some are still sleeping, others are already preparing breakfast downstairs), and over time the temperatures will change 18 ° C and less at the top, and e.g. 19-20 ° C at the bottom.
In general, energy consumption between night and day will be the same, and only the temperature system changes between rooms-floors, depending on the location of the residents, who will hardly notice it and have thermal comfort all the time. This is what I meant in the discussion with piracik.

There is one more detail, although explaining it is the so-called mustard after lunch, but I hope you gave the screeds and tile adhesives at least 2 weeks to dry and stabilize before putting this floor heating into operation.
If not, you can expect cracks in various unspecified places.

saskia wrote:

The basic saving with the floor heating is to reverse the temperature system of the room "upside down", namely the heat, against gravity, remains at the bottom in the zone where the household members are. This is unhealthy in some situations, but saves you money on heating.

It is unhealthy to overheat the floor with a floor, because the temperature distribution is just the most favorable, close to the ideal - physiological

andrzej lukaszewicz wrote:

saskia wrote:

The basic saving with the floor heating is to reverse the temperature system of the room "upside down", namely the heat, against gravity, remains at the bottom in the zone where the household members are. This is unhealthy in some situations, but saves you money on heating.

It is unhealthy to overheat the floor with a floor, because the temperature distribution is just the most favorable, close to the ideal - physiological

That's right, but with gases (ventilation) there is an unhealthy situation.

saskia wrote:

There is one more detail, although explaining it is the so-called mustard after lunch, but I hope you gave the screeds and tile adhesives at least 2 weeks to dry and stabilize before putting this floor heating into operation.
If not, you can expect cracks in various unspecified places.

The spouts were lying for about half a year without heating, the tiles were also off for 2 months, so I think everything will be ok.
I think about the second pump because in order to be able to regulate the flows without any problems, as well as when the temperature at the top or bottom drops below the set value, it is not worth heating the entire system as only a given floor can.

I do not lower the day temperature too much from the night temperature, it is a value of the order of 1 degree. and in total, also changed, because it is at night that the controller orders to heat up the temperature to catch the 2nd tariff, i.e. the floor is heated at night to give up heat later during the day.
Temperatures of 18 degrees are unacceptable for me - (my wife would kill me).
The temperature in the whole house is within 21.3-22.5.


I have mechanical ventilation with a recuperator, so this problem is also solved.

marcel_76 wrote:

I have mechanical ventilation with a recuperator, so this problem is also solved.

I will ask out of curiosity. What happens to the hand when the outside temperature drops below approx. -5 oC?

jack63 wrote:

marcel_76 wrote:

I have mechanical ventilation with a recuperator, so this problem is also solved.

I will ask out of curiosity. What happens to the hand when the outside temperature drops below approx. -5 oC?

I started Reku only 2 months ago with my own design, so far there have been no anomalies in its work
Below the display at an outside temperature of -4 degrees.

marcel_76 wrote:

I started Reku only 2 months ago with my own design, so far there have been no anomalies in its work

Congratulations on your own design. I wonder what exchanger you used, what fans and what controller?
I did not mean anomalies, but the possible operation of heaters to prevent the exchanger from freezing. This is a common practice in commercial trading. The controller turns on the heaters ... quietly and instead of saving we have ... payments.
After that, you write about the outside temperature. -4 oC and the air temperature from the intake "shows": -0.8 oC ??? Could it be GWP? Although it should come out min. approx 6-8 oC.

You did not refer to my proposal to integrate the control in one "larger" controller.
Automation "off the shelf" is expensive and somehow works there in TYPICAL relatively simple cases. It is difficult to call your installation simple and typical, if only because of the hand.

jack63 wrote:

marcel_76 wrote:

I started Reku only 2 months ago with my own design, so far there have been no anomalies in its work

Congratulations on your own design. I wonder what exchanger you used, what fans and what controller?
I did not mean anomalies, but the possible operation of heaters to prevent the exchanger from freezing. This is a common practice in commercial trading. The controller turns on the heaters ... quietly and instead of saving we have ... payments.
After that, you write about the outside temperature. -4 oC and the air temperature from the intake "shows": -0.8 oC ??? Could it be GWP? Although it should come out min. approx 6-8 oC.

You did not refer to my proposal to integrate the control in one "larger" controller.
Automation "off the shelf" is expensive and somehow works there in TYPICAL relatively simple cases. It is difficult to call your installation simple and typical, if only because of the hand.

The recuperator stands in an insulated attic where the temperature varies between 13 and 16 degrees. The inlet on the southern wall, on the external thermometer -4 degrees approx. 1.2 above the ground and the inlet approx. 6 meters above the ground and on a sunny day.
Klingenburg exchanger, ebm past fans, and the control for now is also simple because a regular timer + additional bistable time relay integrated with light switches in the toilets, with time I plan to buy an alres driver, but take it easy - there are more needs.

marcel_76 wrote:

I'm planning to buy an alres driver, but take it easy - there are more needs.

Another driver? Are you planning a collection?
I see you don't understand the problem of frosting on the hand. Let's leave it.

marcel_76 wrote:

The recuperator stands in an insulated attic where the temperature varies between 13 and 16 degrees. Air intake on the south wall,

I do not know what an insulated attic has to an air intake if ... the hand draws in the outside air and the outside air duct is insulated?
An insulated attic makes sense when we want ... to be warmer there than outside. However, for this to be the case, it must be heated directly or through the escape of heat from the storey below it. According to it makes no sense to me, because even with the same insulation thickness, it increases the area of heat leakage from the building, and thus its total losses.
Not only that, it leads to problems with heating the storey under the attic.

marcel_76 wrote:

Klingenburg exchanger, ebm past fans, and the control is also simple for now, because it is a simple timer + additional bistable time relay integrated with the light switches in the toilets,

I didn't mean the company, but the type of exchanger design.
With this arrangement, I assume that there is no gravity ventilation in the house, you may have too little air exchange and / or with higher frosts completely 0!
It seems that I am departing from the topic, but in well-insulated houses, ventilation losses can reach 50% of total heat losses, so the issue of ventilation and heating cannot be treated separately from the CO subsystem.

Hi Mates,

I have just found your discussion here and would like to hear your suggestions for my case.

I have 170 sq.m detached 2 floor house heated by underfloor heating fully. Heat loss is about 17KW and 1100 meter 16mm PERT pipe was used. one manifold was installed on each floor, 1st floor-9 loops, 8 loops on the second floor. Now the system runs only by one circulation pump comes with combi boiler. 1st floor is generally heated better, but 2nd floor is not. There is 2-3C difference between floors. I feel that circulation pump inside combi boiler is not enough to push the hot water to the 2nd floor on 4m height. I was planning to install separate pump for each floor but 2nd floor supply line (32mm) is under floor that cant be reached now. Now I am thinking to install either one more powerful pump on the 1st floor near combi boiler with hydrulic separator to supply for the whole system or one pump on the 2nd floor just before the manifold with mixer to supply only 2nd floor. Which one do you think could be more efficient? how much power should be enough for which option? 25/6 or 25/8 ?

I appreciate any suggestion
Thanks