Water is not filling up and heating in second floor radiators

Discussion in 'HVAC Heating & Cooling' started by chaz1, Oct 28, 2008.

  1. chaz1

    chaz1 New Member

    Oct 28, 2008
    I have hot water radiators and the 1st floor is heating up but the 2nd floor radiators are not filling up with water and heating. I've bled the radiators and also turned the valves on. I have no idea what might be the problem. Please help?
  2. GabeS

    GabeS Remodel Contractor

    Jan 10, 2007
    Remodel contractor
    Brooklyn NY
    do you know if there is water in them? When you bleed the radiator does water eventually come out? If there is no water then that means the pressure may be too low and is not pushing the water up high enough to reach the second floor. My brother's house had the same problem. You may have to increase the pressure until water fills to the top of the highest radiator. If you are not too familiar with the controls then you should get a pro.
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  4. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Sep 2, 2004
    Retired Systems engineer for defense industry.
    New England
    If there are any leaks in the system (an air leak in is as bad as water out), there is probably air blocking the water from circulating to the upper floor's radiators. Is there a bleed valve on any of the radiators? You need to open that until water starts to come out. That is, if the system has an auto fill valve to keep the system properly filled up with water. If it doesn't, you need to open the manual fill valve. It can get tricky, since the pressure in the system is normally only about 13-18 pounds or so, and your potable water system could be three to four times that. You don't want the pressure to get too high.

    It can get a little tricky, and if you don't do it in the right sequence, you can trip a safety interlock or never get it to work. If you don't know what's going on, it can get very frustrating and cause the whole system to shut down until you bring everything back to within tolerance. Things that can trip the safety are: too much pressure, too little pressure, too high a temperature, and many have a max duty cycle where they'll just turn off for a few minutes if they've run longer than X. If the sytem has a flame detector, that's also in the safety circuit - it won't leave the gas on if it senses there's no flame.

    If bleeding the radiators upstairs doesn't fix it, the best thing would probably pay someone to check it out for you, and have them explain and show you what's going on. once you get the hang of it, it's not that big a deal, but there's a lot that can go wrong if you don't understand, and it could put the system into a situation where it won't run at all - not a good thing as winter approaches.
  5. hj

    hj Moderator & Master Plumber Staff Member

    Aug 31, 2004
    Cave Creek, Arizona

    If the system pressure is adequate to fill the upper level radiators, and they are full, then they will heat, assuming there are no other functional problems. If they do not fill with water, then you have to adjust the fill valve until they do.
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