Cold Bottom Radiators: Solutions for Venting, Blocked Filters & Floor Heating Connection

Hello
please help. All the radiators downstairs are cold, and hot at the top. The radiators are vented, the pump is running, and it's also vented. Could something be on the filter and block it partially? Also suspicious is the floor heating (connected to the return of one of the radiators - quite cold). Anyone have an idea? Can there be air anywhere else and how to get rid of it?

Hello
Check the pump near the filter.
greetings

Is this a new installation or do you already know it.
Because when the new filter is clean, this may happen when you have oversized power of the receivers in relation to the furnace.
Look at the flame (if possible) whether it is large or small as it works and the temperature stabilizes.

thanks for both advice, but yes:
1.I checked both filters, i.e. at the entrance and return, I cleaned them, although they were not particularly dirty, is there any other (as you write at the pump - stove vaillant vuw 240 / 2-3)? no resistance, you can hear it working. One thing that is additionally worrying is that it is probably heating up a bit too much - it is so hot that you cannot hold your hand with it permanently.
2. The stove and installation are not new, they have served me very well for 5 years, the trouble has started now.
To sum up: everything is deaerated, nothing has the right to block (unless there is a filter that I do not know about), the pump is working - and the radiators downstairs and the floor heating are cold. I am wondering if there is air left somewhere (e.g. in this floor heating), should an efficient pump push it through? (There is an automatic air vent at the pump). thank you in advance for your advice

The pump will not cope with air-borne floor heating. The output is to refill - slowly and preferably back.

And what are steel or cast iron heaters? Which thermostatic or traditional evalves?
Rinse the installation, each radiator separately, refill by closing the radiators and refilling them one by one. Start with this kind of floorstand ...
It seems to be a resistance to a return that is common to the whole.

steel purmo heaters and thermoregulators. does this change anything in your solution?

Change. A lot of silt can accumulate in cast iron.
Spin all but one and watch what happens. And the filter on the return is ??

the filter on the return is there, I cleaned it but it was not clogged. When I turn off all the radiators and leave one unscrewed, this chosen one heats up very much and even the heat reaches the bottom (although this bottom is still cooler). As I will do it in the case of this radiator with underfloor heating, the heat barely reaches the floor - only the floor near the radiator is warm.
I have noticed one thing - it may be important - which makes the current operation of the installation different from the previous correct operation. In the past, when I turned the valve at the radiator while passing through the opening point of the thermoregulator, you could clearly hear the hissing of the water being pumped. I hear nothing today. Then there is a suspicious pump or something is aired all the time and the pump cannot push it (maybe that's why it heats up so much). I'm already stupid. Someone suggested flushing the radiators one by one, how to do it?

if the pump is very hot, check if it really works
procedure, just in case a bowl under the pump and a towel under the pump to protect the electronics. you unscrew the screw on the pump and use a flat screwdriver to check how the pump turns when stationary and whether you can easily stop it during operation, if so, replace the capacitor on the pump,

warecki wrote:

steel purmo heaters and thermoregulators. does it change anything in your solution?

From what you wrote, the floor heating is from the return of the radiator, right? After the last heating season, did you do any repairs to the installation, or recently drained the water from the installation, if the water was not drained from the system, the reason should be looked for in the pump. It is possible that thermostatic valves require checking, e.g. valve stems, presetting. Air in the radiators is the cold ends of the radiator but at the top, and if they are cool at the bottom, the pump or poor regulation. Check the return temperature at the stove.

One answer is correct: radiators give off heat quickly; are oversized for this weather. When it gets colder, they'll work all over. Sleep well.

mirrzo wrote:

One answer is correct: radiators give off heat quickly; are oversized for this weather. When it gets colder, they'll work all over. Sleep well.

Holy truth . There is definitely no air in it, only the radiator gives off heat quickly, there may be too little flow in the system. I wanted to notice that the air rises up in the water and, as a rule, there is air in the top and most often the last radiator ribs (if the radiator is hung with a bad slope and or there is no vent)

Hello,
in my opinion, the pump does not work properly, the fact that it rotates loosely and you can hear it during operation does not mean that it is pumping.

Pumps of this type get very hot only when the rotor oscillates - it does not spin, it only causes vibrations.

An element which causes (fixes) rotation in one direction is mounted on the impeller of these pumps. If this component is damaged the impeller vibrates.

Another reason may be a short circuit in the stator winding, then the pump will also heat up very much.

The central heating water pump cannot be much warmer than the central heating water temperature.
As you write, the pump is very hot, I think it is a mistake.

Colleagues mention that the return of water from the radiators to the stove may be blocked.
I disagree with that, the pump would be warm but not hot!

greetings
xen

I also have the same problem aluminum radiators mounted with slopes and a vent on each installation new from pp pipes ordinary radiator valves filter clean pump efficient and yet the radiators pits are much cooler than the hot top

It would be bad if the mountain were cold, but here ...
A radiator is a "something" that heats. When it gives off the heat, the water at the bottom of the radiator gets cold and returns to the boiler to heat up. Then she comes back to him and so on. This is very correct. This can be avoided by increasing the flow temperature. However, the house will get too warm and will increase fuel consumption. Unless that's what it is about. Most importantly: is it warm?

It's OK

It also seems to me that the main reason for the described problem is the xen pump, in my opinion, it is right. :idea:

greetings

And when it comes to cast iron radiators? They are heavy, old-fashioned, do not look air-permeable, because air entrainment is usually a colder temperature at the top, not at the bottom of the rib. Mine is warm upstairs, lukewarm in the middle, and completely cold downstairs. Should I get someone to bleed?
It is now around 2 ° C outside, district heating, so the entire radiator should be at least warm. In other buildings, they are all warm.

The fact that they are warmer in another building may indicate that in your building other parameters may be set on the district heating hose, which results in lower refrigerant flows. You should also check the closure and patency of the network in your building.
greetings

Kolorowa wrote:

Mine is warm upstairs, lukewarm in the middle, and completely cold downstairs.

Are you able to determine the temperature in degrees?

Kolorowa wrote:

Mine is warm upstairs, lukewarm in the middle, and completely cold downstairs. Should I get someone to bleed?
It is now 2stC outside ...

And the house is warm?

It is cool in the apartment. I don't know how many degrees there are, but flats in other blocks are much warmer. Due to the lack of a thermometer, I cannot give the temperature, but the radiator can be 15 degrees at the top, 10 degrees in the middle and 5 degrees at the bottom.
I can describe the difference compared to other flats in such a way that when I sit in a room in a warm sweatshirt, at the same time in other buildings you can sit in blouses with short sleeves.

What is the temperature in the apartments next to you in the same building?
greetings

If you have thermal energy supplied from the outside, you go to the cooperative and, referring to the applicable standards, you notify in writing that from ... until now, the temperature in the rooms are lower than according to the applicable standards and regulations, and therefore you require the supply of such amount of heat and in such a form that the required temperature is ensured.
Keep the copy with the acknowledgment of receipt for yourself. There will be grounds for non-payment for the supplied heat in the period from ... to the date of repairing the defect.

PS
Don't talk to them, just exchange letters (with them also everything in writing).

The temperature in other apartments (in other buildings) is over 20 ° C, in my case it is around 15 ° C. I have no way of checking how other people are in the same building, because I don't know anyone here yet.

I know that it would be easiest to call someone from the cooperative, but they come only on working days from Mon. to Fri. in the morning, from 8-9, and then no one is at home.
I can't go out and go to the cooperative too much, because I work at the time allotted for applicants.
I think I will listen to the advice and write there or send a fax if they support this form of correspondence. I don't want to freeze in here.

It is not air pockets, but a bad flow of the heating medium through the radiator. If there was air in it, the first 2.3 ribs would heat up and the rest would be cold and as the top of the radiator is warm and the middle and bottom are cold, there is always a weak flow. If there is a modern thermostatic valve, check the initial setting (you need to remove the head and see how the setting is set - maybe it is set to "1" and the radiator does not heat up at all). Raise the presetting. If the valve is of the old type, it may be simply a muddy orifice, but cleaning requires draining the water and unscrewing the valve. In modern ones, it can also become silt, if the initial setting was minimal (e.g. to 1 or 2) - then you need to temporarily change the setting to the maximum flow (for Danfoss valves it is position N) and such a larger flow will flush the valve. After this procedure, set the initial setting correctly (if it was, for example, at 2 and the bottom radiator was cold, initially set it to 3 and observe, if it is not enough, set it to 4). Note - do not give immediately to the max. especially if you do not live on the top floor, as the tenants on the upper floors might not have heating.

Kolorowa wrote:

It is cool in the apartment. I don't know how many degrees there are, but flats in other blocks are much warmer. Due to the lack of a thermometer, I cannot give the temperature, but the radiator can be 15 degrees at the top, 10 degrees in the middle and 5 degrees at the bottom.

Call the team that manages the heating system in the building. I guess you should specify where it's cold, because if you say the radiator is 15 ° C at the top and 5 ° C at the bottom, congratulations on your ability to recognize temperatures. You are definitely freezing, but you should not solve the mysteries of why the radiator does not heat well. This is why they are professionals, let them have their heads. It is different to live at home, then we can advise on what to do next. I greet warmly.

I had only one radiator at home that was super warm and I started with it by screwing on the power supply, but gradually so as not to lose on the temperature. When I sensed that after a few minutes the return was much cooler than the power supply, I turned the power on by half a turn. After this treatment, I noticed that another heater on the same branch started to heat up very well and I turned it on in the same way as the previous one. The other twigs on which I have panel heaters, I practically did not move and the radiators started to heat up almost sensational. Almost because you can feel a significant temperature difference between the bottom and the top, but now you can feel that the return is warm where it was cold before.
Previously, all radiators, except the ladder, were hot only at the top and the bottom was cold, now the bottom is lukewarm on all radiators.
I hope that the text will help someone because I spent many hours at home figuring out and reading until I came to the conclusion to do as I wrote above.
greetings