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  • Radiators...


    I raised the topic earlier, but now I have to get back to it...

    The apartment where we live in Warsaw had old-style cast iron radiators when I bought it. One in the livingroom started leaking a few years back so those in that room were replaced by aluminium ones. Ever since that change, they make noise, a constant ssshh even when closed. They are louder when open and it is generally annoying. The cast iron ones were dead silent. We survived a few winters, but every winter we keep saying that we will replace them come spring and now we plan to push through.

    So now I'm looking for cast iron radiators... The main issue is that we need a high working pressure (12-16 bar, it is a 20 floor building and heating is not per apartment but in sections in the building), which really limits the choice. Around 13 years ago I thought of replacing them and I found a manufacturer that has nice looking high pressure cast iron radiators, but for the life of me I cannot remember it - I remember I was looking long for it long but I cannot seem to find it now. They looked like a smoother version of the traditional cast-iron ones. So far, I'm running blank on high pressure cast iron radiators, the best alternative I could find is steel.... But of course I don't know if those would be silent (like the original ones), or give the noise like the aluminium ones...

    Anyone here knows good indexes of cast iron radiator manufacturers (or good keywords to start looking for them)?


    Last edited by VJ; 27 March 2023, 03:13.
    Dream as if you'll live forever. Live as if you'll die tomorrow. (James Dean)

  • #2
    Googling "gietijzer radiator" does not suffice?

    I am surprised though by the pressure requirement.I would think that the net pressure would be far lower or that some sort of transition occurs before fluids are pumped into an apartment at 10+ bar?! Assuming you need 2.5bar at location, 8.5bar should suffice, no?
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    • #3
      The problem is that the heating is not like it is typical in Belgium or Netherlands: a single apartment does not have its own furnace or heating system. The building is connected to the city's district heating and has a couple of heat exchangers. The main pipes to which the radiators are connected go vertical: an apartment does not have a single point of entry for the heat. Each radiator connects only to my upper and lower neighbours: my kitchen radiator connects to their kitchen radiators, etc. In this system, the owner of the flat owns the radiator, but its exploitation is the responsibility of the building management (for heating we pay an amount proportional to the size of the flat, no counters or so - although some buildings have radiator mounted calorie meters).
      The building has 20 floors, a standing column of water of 10m increases the pressure with 1 bar, which could give 6-7 bar at the ground level just from the water column. So I can imagine this approach yields a higher than normal pressure. I suspect the plumber claims such a high pressure in order not to have to deal with people putting a very wide range of radiators: once you search above 10 bar you have very little choice, and I suspect that a big variety of radiators may be more difficult to manage. The vertical structure of the pipes may be split at the 10th floor (it has a technical ceiling), but I'm not sure of that and it does not really make much difference if it were. In general the whole heating system is up for renovation according to him, and he has been saying that for 10 years now. But also the building needs to be isolated, and this has 2 problems: cost (of course) and the fact that it is classified as monument, as an example of post-war modernism (any outside changes need permission of the conservator of monuments).

      Anyway... back to the radiators: all the cast iron ones I can find support quite a low pressure (1-2 bar, at most 6-8 bar); the one I managed to find online 13 years ago had an option for high pressure up to 20 bar... but of course I did not write down the make or model and now I cannot find that one. The added problem is that the radiators need to have inflow and outflow at the side and at a distance of 50 cm of each other (most have the option for the side, but not all come in sizes with 50cm distance between them).

      I have found that Zenhder makes steel radiators for the purpose of retrofitting and renovation (model Charleston): they have the correct dimensions to match the old installations and offer an option for pressure up to 18 bar. I'm now considering those, but I'm not sure if they will resolve the noise issue: they will be heavier than the current aluminium ones but still lighter than the original cast iron ones. On the other hand I also don't know if the new cast iron ones would resolve the noise issue. Still, I might risk it with those steel models as I really don't like the look of the aluminium ones: they just does not fit with the style of the building . I just had hoped to find those cast iron ones again, just to increase the chance of the change having an effect on the noise.
      Last edited by VJ; 28 March 2023, 10:13.
      Dream as if you'll live forever. Live as if you'll die tomorrow. (James Dean)


      • #4
        I too had radiator woes. I thought this winter I might pay 100s of Euros for the heating but fortunately the costs were under 100 Euros in January. The city turns the heating down in evening, so If I don't want to be cold If I come late I need to run radiators at Putin levels. (there was a German meme where some dude put picture of Schoelz to 0, Merkel to 1, Schroeder to 3 and Putin to 5 on his radiator dial).

        Last month, I'm about to have performance review work meeting, walk in the bathroom just before, 1cm of water. First thought It was toilet, closed valve but then saw it was radiator. Put the plastic food container under, after end of workday went to borrow some allen keys and closed lower valve.

        Asked new coworkers for recommendations, called one company which installs radiators. They said they need notification from the landlord, emailed landlord, he emails them. 2-3 weeks later finally a dude shows up and replaces the radiator. The dude also had no allen keys and had to borrow one from me (meanwhile I found out the key I got with Ikea is the correct size for the valve). Since I have one of those calorie meters, he said he cannot take away the old radiator and placed it on balcony. Since I'm busy as hell working and freelancing and I also needed to file taxes for my company. I ignore it. Finally notify landlord, building manager but 2 weeks later still nothing. Once I get back I'll give building manager a deadline and then I'm junking the radiator with the calorie meter.

        After living some years in previous apartment I finally found a few good local contractors for air conditioning, plumbing and electricity but now that I moved I need to start from scratch.
        Last edited by UtwigMU; 28 March 2023, 11:51.


        • #5
          I was about to chuck old radiator to recycling center but today some contractor working for heating company showed up and moved calorimeter from old to new radiator. So now my radiator woes are over.