Temperature Setting for Gas Combi Oven: Minimum Temperature, Rust Prevention, Night Shut-off

Hello, and I have a question, I have a pic from Buderus 2-function with a room programmer, I have the stove set to 55 degrees and the programmer to 22 degrees and everything is ok, only the stove turns on and off every 5 minutes and if I increase the temperature on the stove for example, at 60 degrees, he will do it less often and if he will not use more gas, please give me some hints, thank you in advance.

Hello
I will leave for posterity my observations regarding the setting of the furnace temperature, but as a function of gas consumption.
Measured in early December for 3 days, it was a bit colder but not much.
2-function oven, 100 m2 area, 2 floors, 9 radiators, uninsulated house, temperature on the room thermostat set to 21.5 degrees Celsius.
Temperature on the furnace 42 degrees - consumption 7 m3
Temperature on the furnace 52 degrees - consumption 6m3
Temperature on the furnace 62 degrees - consumption 7 m3
Measurement performed every 24 hours. The oven works for about 30 minutes with a 2-2.5 hour break. At a temperature of 42 degrees, the furnace clocked around 3X in 30 minutes.
I understand that the timing is the automatic switching on and off of the stove during the given operation?
Of course you would have to subtract some amount of gas per stove for about minutes a day and a bath 1 bath a day ... I don't know how much gas could go on that ...?
Are my gas consumption results normal?

It seems to me that your hysteresis is too small on the furnace controller. I have 10 degrees set, i.e. when I have 50 degrees, the stove turns on at 45 degrees, and turns off at 55.

I'll raise the topic. Describe your gas consumption.
Here's what it looks like for me:
house 135 m, insulated, two-storey with garage. floor heating on the ground floor, 5 radiators on the first floor
Ferroli two-function oven
Temp. outside about 0 degrees during the day and at night -3 degrees.
Temp. 22 degrees set on the room thermostat (i.e. I want to have 22 degrees / 24h a day at home)
the central heating water temperature is set to 60 degrees Celsius.
daily consumption of 11 m of gas, including water for washing dishes and bathing - a family of 3.

Write what it looks like for you ...

One bath a day can theoretically use approx. 300 liters of gas. These 6m3 seem to be very advantageous (economic boiler) despite the house not insulated (e.g. in Krakow, in the first days of December, it was not very cold, but there were strong winds - it was really frosty at the end of December, although without winds). The timing is caused by the excess power of the stove in relation to the needs for heating the house (note: heating domestic water requires much more power than heating such a house).

Hello after a year.
For me, without major changes, I took measurements again at the beginning of December at a constant temperature throughout the day. There is 1 kitchen and 1 bathroom, consumption fluctuates around 7m3.
As Mr. Zbigniew noticed, a strong wind is very important for me when the house is not insulated. The flat cools down faster around 0 degrees Celsius and wind than at -10 without wind. It seems to me that in this case the most important thing is air humidity.
greetings

akwedukt wrote:

Install a room controller and set the temperature at about 70 degrees Celsius. There is still a boiler power setting, because often 21-23 kW is an exaggeration.

70 degrees jpde. Mega insulated

Added after 1 [minutes]:

akwedukt wrote:

Regarding the car, at which engine speed we have the lowest fuel consumption - at the highest torque and these are not idle engine revolutions.

The biggest rotating monent next. For gasoline it's around 5200 rpm Jesus, what are these statements!

Added after 24 [minutes]:

franc666 wrote:

Hello. I would like to add to the topic.
Two weeks ago I fired the De Ditrich MCRIIT 24 Kw stove, single-function condensate with a 120 l tank. And I have a problem with the temperature at home. I have the water in the DHW set at 47 degrees. But if I do not heat, I have cold or lukewarm radiators on the floor.
The floor on the top will not budge. The ground floor of the radiators is slightly warm, the floor heating is ok. 120m2 is not done this ...
Anyway, I have a cold at home ... The worst on the floor, the difference between the bottom is even 2 degrees.
I have a room regulator in the living room plus a weather sensor outside ... Thermostats in radiators open to max.
I don't know what to do ... maybe someone made something wrong ...?

The answer may be useful to posterity because a cutlet from a century ago. Buddy, the pump is set to the wrong gear, there is air in it or the valves on the radiators are not turned on properly. The point is that if you do not have thermostats, you need to adjust all radiators in the house when it comes to setting the valves so that they heat the same on the return (or when heating in different settings, the return temperatures throughout the house give the same temperature - slightly worse boiler working conditions, but thermally ok ). It is checked by the eye with a hand or with a thermometer on the return, the temperature should be comparable at all (I know that it works if the radiators are well matched to the room, when it is screwed up, it does not work). What does it give? - it means the same temperature of returns, the responsiveness of the entire heating system, i.e. if the radiators are correctly selected, it maintains the same temperature on the whole and condensate appears on the return due to the low temperature (although in this case it is a complex topic anyway - because how is it going? and so it is not known whether it drops the desired or not desirable in the chimney on the exchanger, but the subject is the river flow ...)
One thing is for sure, but here the assemblers pushing 10 pumps and thousands of valves will massacre me. Setting the correct CO operation at low costs is possible 100/100, but it requires time and willingness, and it does not go hand in hand with the cash and speed of work of the masters. It's best to give mixers, pumps, etc., and cancel for this and still have an "allowance" from the store for the material (ha ha ha)

A very important topic. Lots of people would like to know how to optimally set up a condensing furnace. This is the only specific forum where you can learn a lot. Thank you for all your comments. He also tests his boiler with the methods from this forum. It's good to learn something new. greetings

In the instruction manual of my ferroli turbo they wrote that heating below 50 degrees is not recommended. Apparently, more judgment and some kind of carbon deposits are released in the furnace. I stick to it.

old boilers, the so-called the atmosphere or turbo did not use the additional heat, so any condensate was a waste, which in the long run is harmful to these boilers.
The lower the temperature, the more condensate, therefore old-style boilers prefer a higher boiler water temperature and it is better for the boiler if we have more than 50 degrees.
On the other hand, condensing boilers are designed to use additional heat and the more condensate the better, because the efficiency of such a boiler increases. Here, for a change, condensing boilers prefer the lowest possible boiler water temperature, e.g. 40 degrees for radiators or even less for underfloor heating.

There is no single simple answer to what temperature will be appropriate, because every installation is different.
What the boiler water temperature should be in the system depends largely on the size of the radiators and the minimum boiler power.
Additionally, everyone has a different feeling of thermal comfort, and the temperature of the boiler water influences it.
For this reason, one will be OK when the water is 40 degrees, and for another, e.g. 45 degrees, or in the case of non-condensing boilers it can be 50 or 55 degrees.
Everyone should check for themselves what temperature will be optimal for their building and the specificity of its installation and boiler, as well as in terms of thermal comfort.

One important thing. Condensation is only affected by the return temperature, not the flow temperature, and condensation occurs when the return temperature does not exceed 56 degrees (say 55). 55 degrees on the return can be even 70 on the supply (let's say that these would be parameters for a really strong frost - e.g. -20 degrees, which may happen in a given season for one night, two nights, or ... in not happen at all). A typical winter is currently (unfortunately) positive temperatures (i.e. quasi-winter) and if we assumed 70 degrees on the supply for a 20-degree frost, it would be probably 50 degrees outside for zero (up 52), and then on the return it would probably be 40 degrees . It is not advisable to oversize the radiators, because then in March and November you can have a sauna inside, even if the radiator is not warmer than women's backs.

Zbigniew Rusek wrote:

Condensation is only affected by the return temperature, not the flow temperature, and condensation occurs when the return temperature does not exceed 56 degrees (say 55).

You repeat it like a mantra on many threads, but in my opinion, without additional reflection, this mantra makes no sense.
As a rule of thumb, you are right about condensation going up to let's say 55 degrees on the return.
But the condensation is different at 55 degrees on the return and different at 30, and therefore manufacturers boast the highest efficiencies for a 30-degree return, not 55.
The flow temperature is directly related to the return temperature, so you do not make a big mistake with the generalization of the flow temperature.
At low flow temperatures, the difference between the supply and return can be 5-10 degrees, so a 35-40 degrees supply will provide 30 degrees on the return. At higher temperatures, the difference usually increases and can reach 15-20 degrees. Yes, if someone wants, they can have 50 on the supply and 30 on the return, but I feel better if the radiator is as warm as possible, and this requires a small difference. If the difference increases, the top gets warm and the bottom gets cold.

Zbigniew Rusek wrote:

55 degrees on the return can be even 70 on the supply (let's say that these would be parameters for a really strong frost - e.g. -20 degrees, which may happen in a given season for one night, two nights, or ... in not happen at all)

With 70 degrees on the power supply, we have hot radiators, which may cause burns. In the past, people heated water to 90 degrees in frost, and they were alive too. But I do not know if someone would like to have such hot heaters at home nowadays, having children, or elderly people, etc.

Zbigniew Rusek wrote:

It is not advisable to oversize the radiators, because then in March and November you can have a sauna inside, even if the radiator is not warmer than women's backs.

Bending with everything is not advisable, but I do not consider the selection of heaters to the 55/45 parameter for frosts to -20 to be a bad thing. It all comes down to the cost and technical feasibility of assembly.
In an old, non-insulated building, the demand for energy is high, so the radiators require large sizes and this makes selection to low parameters difficult, because, in principle, it requires the use of 3-plate heaters, and their aesthetics are debatable and the costs increase significantly.
In turn, in a modern building the demand for heat is low, so ultimately the radiators do not have to be huge, and this facilitates selection for a low temperature and reduces costs and does not spoil the aesthetics.

There will be no sauna either, because having appropriate regulation, the boiler will turn off the heating early enough and in the transitional period, instead of heating non-stop around the clock, it will be turned on at most a few times a day. In many modern buildings, the boiler will usually have to clock anyway, but switching the boiler on for several times a day is not a bad thing. It looks completely different when someone's boiler is turned on several dozen times a day.

They should be selected for the parameters 55/45 at the temperature between 0 and minus 5 degrees (which is still lower than it prevails during most of the winter). Generally, I advise against the use of high radiators, because each radiator is (unfortunately) warmer at the top and bottom, and warm air - as lighter - goes up and cold air from the windows (especially from the door) down, hence, among high heaters, we can have an oven under the ceiling and freezer next to the floor. the radiators should be as low as possible (to heat mainly from the bottom, especially as you usually get cold from your feet - especially when you are sitting). 90 degrees (sometimes made in this way in coal boilers) is a temperature that poses a risk of serious burns (such a hot radiator should be secured with a grille).

Zbigniew Rusek wrote:

They should be selected for the parameters 55/45 at the temperature between 0 and minus 5 degrees (which is still lower than it prevails during most of the winter).

Why should they?
I subjectively prefer when the radiator is below 40 degrees, i.e. 37 degrees at the top, which for a difference of e.g. 5 degrees would give boiler water 37/32.
When the supply water is 55 degrees, it is too high a temperature for me, not very pleasant and comfortable.
Mostly cold, I would rather have a temperature of 40 degrees on the radiator than 55 or 50.

Zbigniew Rusek wrote:

radiators should be as low as possible (to heat mainly at the bottom, especially as you usually get cold from your feet - especially when you are sitting)

Even low heaters will not completely eliminate the problem of cold feet.
On the other hand, what if in theory it is better to have lower radiators, but with a space of 90 cm between the floor and the window sill, I certainly would not like to have a 30 or 20 cm high radiator, because I would have a decor like Alice in Wonderland.

Instead, in a new building, I would put a floor covering, not feel the heat source, the floor is neutrally cool, and yet there is a feeling of a warm room. In addition, we gain space for radiators, but the floor heating also limits the arrangement options, so each solution has its advantages and disadvantages.

In the case of radiators, it would be best to have a heat buffer that will make the operation independent of the burner operation cycles in the boiler and then we have more possibilities in terms of heat dosing to eliminate the potential effects of the thermal sinusoid, i.e. excessive overheating or underheating of the rooms.

Added after 1 [hours] 29 [minutes]:

I allowed myself to make small calculations.
Suppose we have a radiator suitable for 55/45 boiler water for theoretical frosts of -20.
The average temperature in winter is at the level of +2, so on average we will need 45% of the power that comes out to the theoretical computational frosts of -20.
Keeping a more or less similar water flow through the radiator, it comes out that the condition of 45% power will be met by boiler water with a temperature of approx. 39/34.
In other words, for radiators selected for the 55/45 parameter in the winter season, boiler water with a temperature of 39/34 is on average enough.