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radiator "poping"/ticking noise

Hollis Member Posts: 105
Expansion noise of a cast iron radiator,...I'm trying to figure out where it coming from. Maybe its the pipe thru the floors hitting wood? or would it be coming from parts of the radiators. Not terrible but for light sleepers,when the heat is coming up, it pops,ticks ect enough to wake both my wife and I up,..any ideas on what to do or is it a part of dteam heat that you accept? 


  • Hap_Hazzard
    Hap_Hazzard Member Posts: 2,846
    It could be either

    Usually if it's the radiator, you'll hear a "ping!" caused by the vibration of the truss rods that hold the radiator sections together, unless someone has gobbed so much paint on the radiator that they can't vibrate.

    When a pipe is rubbing against wood it makes more of a "clack-clack" sound or a dull knocking sound, but it doesn't sound metallic unless the movement is close enough to the radiator to transfer some of the force of the movement to the radiator.

    To isolate the source of the noise, check and see if it is happening while the radiator is warming or just before. You can also use a welder's glove or oven mitt to feel different parts and see if you can deaden the noise by applying pressure with your hand.

    If the noise is coming from the pipes moving against wood, you can sometimes quiet the noise by dusting the area with talcum powder (real talc, not the corn starch baby powder) and brushing and blowing it into the gaps, but this only works temporarily. If you can work some PTFE thread seal tape in between the pipe and the wood it will last a little longer. Another approach is to use high-temp silicone sealant to seal the area of penetration and deaden any movement.

    If the noise is coming from the radiator, it's not going to be easy to fix. Most radiators have their sections connected by tapered push nipples that form an opposition fit when the sections are drawn together by the truss rods. If the truss rods aren't tight enough or the tension isn't uniform, the push nipples can back out of their sockets when they expand, pushing the sections apart slightly, until the tension of the truss rods keeps them from going any farther.

    I haven't done this yet, but I suspect what's necessary is to take the radiator apart, replace any worn push nipples (or maybe replace them all to be on the safe side), put it back together and torque the truss rods. I don't even know where to find the torque specifications yet or if they are even available, but if all else fails I can compare them to some of my other radiators that aren't making noise. You can tell when two rods of equal length are at the same tension by the sound they make, and tension is actually more important than torque.

    I'm going to be working on a couple of my radiators this summer, so I'll probably know more about this then, even if it's just the name of a good local shop that does radiator rebuilding.
    Just another DIYer | King of Prussia, PA
    1983(?) Peerless G-561-W-S | 3" drop header, CG400-1090, VXT-24
  • Jamie Hall
    Jamie Hall Member Posts: 23,284
    Expansion noises

    can be extremely difficult to find, never mind fix.  Hap's suggestion to see when they occur in relation to when steam hits the radiator is excellent, and should help you locate where they are coming from.  If they are in the feed pipe, make sure that the pipe isn't touching wood anywhere (if it is, try slipping a piece of plastic milk bottle in there -- it sometimes helps).  This doesn't always do it, though, as sometimes the noise is in the pipe itself, as it moves and the threaded joints give a little (which they should).

    If it is in the radiator itself... an easily fixed one is the feet of the radiator on the floor -- try the plastic milk bottle trick again.  However, if it is from slight movement between the sections of the radiator, about all I can say is "good luck".

    If you should be inclined to take the radiator apart, or adjust the tension in the tie rods (if it has them -- not all do), work very carefully.  This is not an easy job.  On the tie rods, refrain from torquing them up too tight -- just tight enough so they don't rattle when the radiator is cold is ample (on clean threads, finger tight plus a half turn)(there's your torque spec., hap).  It is dismayingly easy to break them, or strip the threads, and dismayingly difficult to get replacement parts.  They are NOT made to pull the radiator sections together -- just to keep them from creeping apart with time.  To pull the sections together on reassembly, use a pair of pipe clamps and tap (don't whang) the sections as you pull them up with the clamps evenly.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • Hollis
    Hollis Member Posts: 105
    thank you gentlemen,..

    I'll try to isolate the sounds and try the milk bottle plastic in the floor,..but I will probably stop short of trying to take the sections apart unless it gets worse.

    You gave me a thought about perhaps putting those "sliders" they use to move furniture. I saw some that I think were made for wooden chair legs to stop them from floor scuffing, I think they are also teflon coated (or similar) Anyway I think they might slide w/o noise.

    Wondering too if I sprayed a small amt of silicone spray with a snorkel  to hit any joint that looks like it could expand if it might at least isolate what  is making noise (if it indeed does work to make the expansion noise less).
  • FJL
    FJL Member Posts: 354
    Clicking Sound

    I had this problem and it went away after a few heating seasons.

    We placed a feed pipe that had become back pitched. The water hammers went away but in very cold weather the pipe would emit several clicks as the steam traveled through the pipe, which was located right under the floor in my bedroom. The noise was loud enough so that I could always tell when the heat had turned on and often woke me up. This heating season, however, that noise has disappeared.
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