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One 2nd floor radiator never gets really hot - sludge, valve?

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SteveMaryland
SteveMaryland Member Posts: 2
edited December 2022 in THE MAIN WALL
I own a 1927 bungalow with a 1938 retrofit hydronic radiator system. 2 floors, 4 radiators per floor. No zones. Each radiator connected in parallel. Gas furnace with circulator pump.

I recently replaced 7 of 8 of my old leaky radiator valves.

My system heats up OK but one 2nd floor radiator gets lukewarm and never gets hot.

Tried throttling every other valve + air bleeding all radiators but one is still lukewarm.

Also, from infrared photos I notice that on every radiator, the intake is valved except for the "lukewarm" radiator - it looks like the return is valved. Should the valve always be on the intake side?
Maybe manifold sludge blocking? I don't know and I don't know how to flush it out or if it should be flushed. I don't want to make things worse on this old system.

Comments

  • Jamie Hall
    Jamie Hall Member Posts: 23,567
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    That is a little odd. Make sure that the piping to that radiator didn't somehow get reversed. Also make sure that the control valve is fully open -- and that it is working. Reverse flow through that type of valve will aggravate any potential problems with the valve, as it will tend to close it rather than open it if something is loose in there.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 8,157
    edited December 2022
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    YEA... That is piped wrong. Someone messed up somewhere. You may need to find a place where it is easy to reverse the piping to make the valved pipe the supply and the bottom pipe the return.

    Edward Young Retired

    After you make that expensive repair and you still have the same problem, What will you check next?

  • Long Beach Ed
    Long Beach Ed Member Posts: 1,215
    edited December 2022
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    Diverter tee system with a bad valve or fouled tee venturi?
  • mattmia2
    mattmia2 Member Posts: 9,850
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    Did this ever heat? Maybe they are both connected to the same main?
  • SteveMaryland
    SteveMaryland Member Posts: 2
    edited December 2022
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    Thanks guys for your comments.

    That radiator has always (since 1938) been plumbed that way but the lukewarm problem is new.

    Why would the valve location matter?

    One thing for sure - this radiator does fill up and it never has any air.
  • mattmia2
    mattmia2 Member Posts: 9,850
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    You could open up the new valve and make sure there isn't some issue with it.