Steam radiator (C) Daniel FriedmanBanging Pipe & Radiator FAQs
Q&A on fixing banging, clanging pipes & radiators

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Steam & Hot Water Heating Pipe, Boiler or Radiator Noise Diagnosis & Repair:

This article explains the causes and cures of noisy or banging heating pipes and radiators in steam heat systems. We describe different noises made by heating steam or hot water heating systems, how to track the noise to its cause, & how to cure the problem.

We discuss the following: Banging Noises at the Steam Boiler, pipes, or radiators. Causes of noise problems in hot water and steam heating systems: air bubbling, banging, clanking, creaking, hissing sounds and what they mean, how they are fixed. How to shim the one pipe steam radiator to cure banging, clanging, pistol shot noises at the steam radiator.

Banging radiators, clanging heating pipes, bubbling noises, creaks, hisses, pops, and the like are diagnosed & fixed by these procedures.

Green links show where you are. © Copyright 2017, All Rights Reserved.

Steam Heat Piping or Radiator Banging or Pounding Noise Diagnosis & Cure

Low water cutoff (C) Daniel Friedman

These questions & answers about banging or clanging radiators or heating pipes were posted originally at BANGING HEATING PIPES RADIATORS - home, where you will find description of different sources of and cures for banging and clanging noises in different types of heating systems including hot water heat and steam heat.

On 2017-11-07 by (mod) - banging noises somewhere in heating system after valves replaced


I don't know what valves were installed where on your boiler, but it's possible that the banging you hear is from having cleared out a hot water flow blockage that in turn increased the water flow velocity, combined with typical causes of banging pipes that occurs when a pump stops or a zone valve closes.

It will aid in the diagnosis of this annoying noise to start by noting just where the sound is emanating: from radiators or pipes or at the boiler.

Take a look at the six categories of banging heating pipes listed at the start of BANGING HEATING PIPES RADIATORS - one of those sections chosen to match the kind of heating system you have, probably



ZONE VALVE BANGING or BACKWARDS - separate article

Also read WATER HAMMER NOISE DIAGNOSE & CURE - to understand why banging pipes occur in water systems.

On 2017-11-07 by Eresena

We have hot water heat. New valves were put on our boiler to replace very old ones that were corroded.. We have 4 zones. When we adjust the thermostats, we hear loud banging noises. What is causing this? How can this be stopped?

On 2017-10-31 by Jeannette

I hear loud banging noises about an hour after my heat is on. I have hot water heat. The next noise every 2 to three hours after that .
What is causing the noise.

On 2017-10-20 by (mod) - radiators rattle when the wind blows

That's a bit baffling, Penny, I agree, since the hot water piping and radiators in a forced hot water system are a closed system that is not connected to any normal wind-affected building component. Perhaps narrowing the sound down to one specific radiator would point then to a nearby noise source in or on the building itself.

See WIND NOISES at BUILDINGS for additional ideas that might help track this down. Keep us posted as what you find will help other readers.

On 2017-10-20 by Penny Parrott

Every time the wind blew last night rattling seemed to come from my radiator, any ideas what is causing this.

On 2017-04-08 by anon -

Or on a steam system, condensate collecting where it should not.

On 2017-04-08 by Glenn

Loud banging sound installed 4 months ago could be air in system 2 zones Weil McClain csg gold boiler

On 2017-04-01 by (mod) - drain excess water from the boiler and fix the feed valve


Your service tech should be able to drain the excess water from the system right at the boiler drain. Automatic water feed valve, assuming you have one, should not begin to add makeup water to the boiler and tell the level drops much slower.

On 2017-04-01 by Hilary

We have water hammer in our steam pipes in the basement. Overfilled the boiler to make up water and some went into the steam riser and then into some of the basement ceiling pipes. Is there a fix for this problem? Thanks!

On 2017-03-27 by (mod) -

Ask the plumber to examine the system to find the specific component that is causing the noise - typically a valve that is closing too rapidly for the system's pressure.

On 2017-03-27 by Linda castellino

Six months ago I had a new gas furnace installed with an automatic water feeded. Since then I have had banging pipes. And water coming out of the radiator valve. My plumber pitched all the pipes, changed the varivalves with maid of mist valves, put a check valve with a door in it for the vaccuum.

It is still banging and the water in the gauge goes all the way down. He also had a compressor to check for blockages, what should I do?

On 2017-03-21 by (mod) - banging noise after new steam boiler installed

If the steam system wasn't making banging pipe noises before but does make them after a new boiler was installed I can but suspect that there is a problem with the condensate return piping.

You and other tenants can make sure that steam vents are working on your radiators and that noises are not coming from the radiators themselves - that would suggest that maintenance is needed at the noisy radiator.

Else you might let the manager know that there's a problem that may lead to other more costly or even safety concerns present any time a steam heating system isn't working properly. For example banging steam piping can disturb a temperature/pressure relief valve, causing it to leak; over a longer term a leaky relief valve may become unsafe.

On 2017-03-21 by Harry

Landlord recently had new steam heater installed. Since then, the pipes heading to the radiators bang constantly. I don't know why he doesn't call them back? Probably a money issue. What can we do ourselves? My friend is a maintenance man at a large apartment facility, but they do not have steam system.

On 2017-03-04 by (mod) - increasing system temperature won't get rid of excess water from a steam radiator

No Edward, increasing temperature or pressure won't remove "excess water" from a steam radiator. "Excess water" is not a normal condition in a steam radiator. If your steam radiator actually contains an accumulation of water (condensed steam) then more-likely the radiator's condensate return line or water exit point is rust, crud, and debris clogged.

On 2017-03-04 by Edward

Is it possible to remove excess water from a radiator by increasing the temperature to 85 degrees or higher using a steam boiler, because the heat from the steam will transfer to the water causing the water to become steam.

On 2017-01-14 by (mod) - surging problems in steam boiler

Surging can be a problem in steam boilers, Sam. And indeed surging steam boiler water can be a cause of banging sounds in the steam heat system.

You don't say why draining 20 gallons was recommended by "a plumber" - this sounds plausible but perhaps a bit arbitrary as I will explain.

We do not normally "drain" steam boilers unless as part of boiler cleaning.

We DO normally and frequently, perhaps weekly, flush the low-water cutoff valve (LWCO), a critical safety device that requires flushing to avoid debris-clogging inside the valve. That process will remove some water from the boiler along with sludge and crud from inside the valve body.

When water is drained by the LWCO flushout makeup water must be added to the boiler. Typically water is restored by an automatic water feeder valve though on some steam boilers water may be added by opening a manual water feeder valve instead (not a great system).

If your boiler failed to add enough water you might see surging.

The most-common cause of surging in a boiler is too much sludge, dirt, rust, debris in the steam boiler. Experts call this steam boiler problem "priming", and you'll see the water in the boiler sight glass bouncing up and down - a problem distinct from "foaming" - the presence of foamy bubbles that might be seen in the boiler sight glass. (Foaming may be due to boiler water that needs treatment to reduce a too-high pH or alkalinity.)

That might be a reason that a boiler has to be drained and cleaned.

Just arbitrarily "draining some water" from a steam boiler is not sufficient in my OPINION - though I'm no Dan Holohan. But draining an arbritrary amount of water to flush debris from the boiler itself (through the boiler drain not the LWCO) might not work.

Instead you may need to drain water until the water coming out of the boiler runs pretty clean, re-filling along the way as needed.

You might have to do this several times as more sludge-crud may be returning to the boiler from the steam radiators by way of the condensate return line.

Watch out: it's best to do large-volume boiler flushing when the boiler is cool or cold. Running a lot of very cold water into a very hot boiler (steam or hot water boilers both) can cause thermal shock that could crack the boiler - destroying it.

A very thorough and detailed article on steam boiler foaming and surging, listing additional causes and cures was penned by Dan Holohan at - an independent website not connected with Mr. Holohan's article is at

On 2017-01-14 by Sam S

I drained (about 20 gl of water) my steam boiler as was recommended by a plumber, and all of a sudden that day water started to surge in glass gauge and one of the radiators in the house started spitting water and hammering. Any recommendations? Tks!

On 2016-12-04 by I

Turn the heating system on makes all these loud banging noises in the pipes after it gets hot it stops when it starts up again does the same loud noises

On 2016-11-08 by (mod) -


On 2016-11-08 by judy

the riser in one room comes on tinging for 2-3 hours, the heat person has come a few times to no avail yet,
now the other room has the riser clanging, opening the radiator valves has not helped, they all just clang!! any advice??

On 2016-11-07 by (mod) - Close the valve to the leaky radiator

Close the valve to the leaky radiator; It sounds as if there's both a valve leak and perhaps a blocked condensate return line.

On 2016-11-07 by Anonymous

hearing water bubbling up in radiators and water pouring out one valve in a radiator, new steam boiler

On 2016-01-12 by (mod) - fixing an air bound heating system

Wayne, try the more thorough air bleeding procedure by searching for AIR BOUND HEATING

On 2016-01-12 by wayne

2nd floor got water facilitator on a loop system and at the end of loop,got to keep bleeding that radioisotope all the time to keep it hot

Question: sound at steam radiators in off position

(May 19, 2011) dave said:

I want asking about if have sound air/steam in my heating radiator and a little bit warm eventhough on the position turn off ? What i must to do if like that? Thank you for your help.


If your steam radiator is turned "off" at its local radiator valve but it is still getting warm, then the radiator valve is not fully closed. It may be that the valve needs to be replaced.

If your steam radiator valve is turned "on" and gets warm normally but the steam vent on the radiator never stops hissing at all during the heating cycle, then the steam vent itself may need replacement - a simple and inexpensive repair.

Question: slapping sound at heat pump

(Dec 5, 2011) carolyn garza said:

Our heat pump makes a loud slapping sound at various times. I don't think it makes this noise when the motor is on.

Question: towel radiator needs bleeding

(Jan 12, 2012) Robert Hobson said:

We have one towel rail radiator and water tank heated from a stove back boiler. The radiator needs bleeding every time we heat the water up and switch on the pump. Could we fit an automatic bleed valve to the towl rail to cure this?


Probably but why not give the manufacturer a call to ask them. They may suggest a strategic vent location that is upstream from the towel radiator.

Question: Crown boiler air purger not needed?

(Feb 2, 2012) Peter Kurtenbach said:

I have just had a new CROWN TWZ065 boiler instaled.
The instaler said my air purger was no longed needed & removed it.
I now have noise in my base board. They have tried to purge it 4 times.
I belive it is because the air purger was removed. was he right?


Removing an air purge is ok IF there is another adequate air purge in the system such that you're not leaving an air trap

Question: house is too hot after changing a leaky valve on a gas boiler

(Feb 4, 2012) Tony Caputo said:

I have a gas hot water boiler. Recently I changed a leaky valve. I then bleed the system and put it back on.
Now I notice the house being very hot.

The circulator is off and I have hot water going through my baseboard.
what can cause this.

Also each zone has it's own circulator and the other zones are ok. the zone that I changed
the valve is the one where water is flowing without the pump being on.


I suspect that a zone check valve is stuck open


(Oct 23, 2012) David Bala said:

I have a Oil burner steam/cast iron radiator heating system im my home. The last radiator (in the upstairs heating sequence)radiator often bangs.

It also will often spit high amounts of hot water as if it is a faucet) out of the pressure valve when the furnace is activated. Do you have any suggestions?
Thanks in advance,


Banging radiators are discussed at BANGING HEATING PIPES RADIATORS


(Nov 9, 2012) Prudence said:

Cape Code style home built 1950's- 1 pipe system- exactly as shown at BANGING HEATING PIPES RADIATORS . 1 1/2 years ago new boiler/burner and pipes to and from boiler/burner to radiator(s) pipes replaced. New bleeder valves ( left in open position) installed on radiators. 1st season( last year) all appears fine, until end of season when loud bangs could be heard.

Shortly thereafter, heat was off for summer. No seperate hot water heater- burner ran over summer only for hot water.

No banging to be heard. Recently turned heat on. Within 10 minutes heat coming from radiators and LOUD banging began. Turned off thermostat. Hour later turned heat on, In attempting to pinpont location of bangs,observed water flowing down basement wall, at point beneath an upstairs radiator.

Turned off thermostat- checked water level in glass tube = full and dirty. 1st plumber drained bolier, water level back to 1/2 mark.

Approx 6 minutes later, all appeared ok. Plumber left. Within few short minutes discovered water spewing out from bleeder/seeping from pipe (leading into radiator-see photos in BANGING HEATING PIPES RADIATORS pipe bottom right-from floor into radiator ) on radiator located above where water was discovered flowing down wall in basement.

Turned off thermostat- called plumber who advised I seek steam experienced plumber. Next day, with thermostat off, water tube was again, filled to top- water clean in appearance. Next plumber came in, again drained boiler until water in tube was at 1/2 way mark.

Without turning heat on, plumber's assesment is pipes from burner/boiler to radiators are not angled correctly. Advises pipes be removed and reinstalled at correct angle. States job is very labor intensive.

Question. If plumber is correct, culprit = current position of pipes, why issue now and not last season? Desperate for assistance. Fearful to turn heat on and very cold here= fearful of pipes freezing. Extreme difficulty in finding experienced steam heat plumber. Any and all suggestions greatly appreciated!


Prudence, you might search InspectApedia for "Banging radiator pipes" or Banging Steam Pipes for more diagnostic details;

in general I suspect a condensate return problem. Indeed if the boiler changeout changed the slope of a condensate return pipe ANYWHERE in the system that will often cause a condensate return blockage - condensate needs to return to the boiler by gravity.

If your plumber can point to improperly sloped pipes it sounds to me as if s/he's on to the problem and probably knows more than either of us.

Question: trouble with automatic water feeder

(Feb 13, 2014) Anonymous said:

i have a water automatic feeder.but in the morning is goes up about more than 3 gets to the point that feed all away up.than after couple of days it bangs so much especially in the morning. i have to drain so much water in order to quite dawn

. i called a plummer is telling me to avoid the noice. but i cant helped it makes to much noise that even water had come out. they said that the water feeder is ok. who could help me

Sept 26 2014 Patricia Kimball said:

Within the last 3 months our copper pipes makes a loud banging when the furnace pumps hot water thru the pipes.

Tried draining, didn't help. Have a filtration system that doesn't seem to be involved. For 18 yrs. there was no problem--no recent alterations to the system. Would appreciate any suggestions.


Banging steam pipes, discussed in BANGING HEATING PIPES RADIATORS give some clues, Patricia, but I'd add that we need to ask what has changed. Even if the system has not been knowingly altered, rust and crud in condensate system piping can clog a return, for example.


Question: banging copper pipes when the furnace pumps hot water thru pipes

(Sept 25, 2014) Patricia Kimball said:
Within the last 3 months our copper pipes makes a loud banging when the furnace pumps hot water thru the pipes. Tried draining, didn't help. Have a filtration system that doesn't seem to be involved. For 18 yrs. there was no problem--no recent alterations to the system. Would appreciate any suggestions.


Look for blocked condensate return or radiators sloped the wrong way.

Question: loud banging pipes when the heat kicks in - can I insulate the radiators to control the noise?

(Oct 3, 2014) Emma said:
I live in new York with a steam pipe and radiator system. i'm going into my 3rd winter here and when the heating kicks in, the pipe bangs loudly and sounds like someone is hitting it with a hammer.

I think this is water hammer. the building has 36 apartments and they aren't willing to do anything. they've checked the radiator and pitch is ok. It's the pipe and they system that is probably old and dirty. This wakes me a disturbs my sleep many times a night and made me ill last year

I've written to the landlord many times and even withheld rent last year. It hasn't helped. I'm worried about it happening again this year and may have to move out. I wonder if there is any type of lagging or soundproofing you can recommend for the pipe that may help to reduce the noise. I'm desparate! Thanks



I am doubtful that insulating steam heat radiators or piping is going to be a happy solution to banging pipes - as it risks interfering with heat transmission; more likely what's needed as a steam heat tech to diagnose and fix the banging pipe cause.

Question: Boston building: what's the role of the condensate reutrn

(Nov 4, 2014) Luiz G said:
I live in an old(over 100 yrs) building in Boston. One boiler for 6 apartments in 3 floors.

Our steam heating is one-pipe system. What is the role of the returning water from the radiators to the boiler operations? If one apt wants less heat and uses the regulated vent to obtain it, more heat will go to the above apt which can do the same process and more heat will flow to the whole building. Are they helping save money as the heating cycle could be shorter?


Condensate in a steam heat system returns to the boiler to be heated again into steam to provide more heat. If we didn't get rid of condensate from the radiators they'd all stay cold as water would prevent steam entry; if we didn't return condensate to the boiler it'd use more water than necessary, speeding boiler corrosion, reducing boiler life.

Luis the condensate returns to the boiler to be re-heated to make more steam. If no condensate returned but say were dumped into a drain the boiler's water usage rate would skyrocket as would the heating cost while the life expectancy of the boiler would diminish.

Question: loud heating pangs in Marshfield Wi - wiring question?

(Nov 6, 2014) Adarious said:
I recently moved into a house in Marshfield WI. If I had to guess the age of the house I'd bet it's at least 60 years old (many of the rooms have 15A breakers installed which would originally have been fuses...and suggest 12-grade wiring).

The house was converted to an upper and a lower...presumably as cheaply as it could be done. It is using water radiated heat which is heated by gas.

Every time the heat comes on, within a minute loud pangs and sometimes rapid not-so-loud (like a cooling car radiator but louder) sounds come from the area of the radiators themselves. The landlord is an aged man and whenever I have brought up things that need to be done (such as better breakers) I get told to do it.

That said, what options can you suggest in order to alleviate such loud noise? I live on a fixed budget, so I cannot afford expensive remedies, but I would like to be able to do something about this.



15A circuit breakers would normally be paired with #14 gauge copper electrical wiring. #12 copper wire (which would be fine) would support a 20A circuit.

Of course if your wiring were aluminum then the rules change and you'd see #12 aluminum wire on a 15A circuit.

That has nothign to do of course with banging noises. Our best advice on reducing banging radiators and pipes is in BANGING HEATING PIPES RADIATORS


(Dec 4, 2014) Martin said:
I have a central heating system working on a control system .All the radiators have electronic actuators to control the temperature , these fit on the top of the thermostatic rad valves.
The heating has started to bang very very noisy as if there was a maching gun going off.
Anyone got any ideas?


Martin do any of the banging pipe explanations in the article BANGING HEATING PIPES RADIATORS suggest help for your system?

If not, tell me what's changed since before the banging.

Question: can't turn off the heat

(Dec 16, 2014) Fiona said:
I live in a 100 year old historical building where we have radiator heat regulated from one thermostat in the lobby for 50 units.

We cannot turn on, off, up or down our heat. I've been here a year and a half and every time the heat comes on the pipes bang like someone's hitting them with a hammer, and it's right next to my head when I sleep. It gets so hot in here, I have to open all my windows, in winter, or leave.

The digital thermometer works, sure, but it does not do a thing to the heat. They're coming in again today to "check" it. My question is this: do they have the ability to turn off the heat at my unit? How is that done? I'm done with this thing and just want it off.



By installing a thermostatically operated radiator valve every radiator can be individually controlled to regulate room tempeature;


Question: moaning whining noise from the cellar

(Jan 7, 2015) Annie Keller said:
I have an old house with radiator heat. I've been having a moaning, whining noise coming from my cellar, my brother says it's not the water heater, it's the boiler. It only happens when the winter temp gets to a certain coldness, the colder it is outside, the louder and more consistent the whining is.

I say maybe the boiler can be insulated to avoid the noise, my brother says the boiler can't be insulated. Who's right? Thanks ahead of time for any input you may have.

The whining is coming from the cellar - from the actual boiler itself, not from individual radiators in the house. The whining only happens when the temp outside gets to a certain low and the colder it is outside, the more and louder the boiler whines. Not sure how individually regulating radiators would solve the problem in the cellar.

The radiators themselves are working perfectly fine. Is there such a thing as boiler insulation or a boiler cover to keep the boiler from frigid temperatures in the cellar? It's an unfinished cellar with no heat. Thanks for your response ahead of time....


21 Feb 15 susan said:
Check that your pipes are firmly hung. My pipe was drooping cuz a pipe holder let go .Major banging occurred.

Question: loud banging noise 15 minutes after the thermostat kicks the boiler

26 Feb 15 Cathy said:
I have single pipe steam radiators in my house, and just this winter, the radiator in the bedroom started making very loud banging noises about 15 minutes after the thermostat kicks the boiler on.

It wakes me up nearly every night. I took a level and made sure that the radiator is pitched appropriately. I also make sure the valve is open all the way, and I cleaned the vent with vinegar, and it seems to be releasing the air just fine.

The bedroom is on the first floor and sometimes the pipe beneath the floor sounds like someone is hitting it with a hammer, and it's enough to shake the floor. I called my plumber, and he said that it's not likely that this is something that can be fixed. He said he could spend a lot of time troubleshooting and still not find the cause. Any ideas on what the issue could be? Thanks!


We discuss the typical causes of banging steam pipes in BANGING HEATING PIPES RADIATORS. I don't have better suggestions; your plumber is doubtless correct: the problem can be fixed given correct diagnosis. Usually people start by looking for a blocked condensate return.

Question: loud banging steam pipes

(Mar 5, 2015) said:
We recently moved into a house that was built in 1918. The house has steam heat with a return system, at least that is how it was explained to me by the heating company and a steam heat "specialist". There are return pipes.

The banging is loud and lasts a bit then stops. The heating company sent a man who said change a valve in the basement but we can't. There is cement wall where you would turn that valve.. an addition from 2009.

The banging is on the older side but then again there has been changes to the old side too. My husband thinks the pipes are sloped wrong. The heating company and heating specialist say the return pipes are not sloped wrong. Nevertheless we can't find someone who is willing to try to diagnosis it and fix it. Any suggestions?


You need to ask your heating company to send an experienced steam heat technician. Commonly you'll find a clog in a condensate return line, radiator outlet or elsewhere. You might ask, if someone thinks a particular valve s the problem, how they tracked the banging pipe noise to that point as it would increase our mutual confidence in starting the troublesome repair.


Continue reading at BANGING HEATING PIPES RADIATORS or select a topic from closely-related articles below, or see our complete INDEX to RELATED ARTICLES below.

Or see this

Article Series Contents

Also see SOUND CONTROL for PLUMBING for an extensive list of causes and cures of building plumbing noises.

Also see NOISES COMING FROM WATER HEATER for the diagnosis and cure of clanking or thumping noises that may be coming from your water heater or heating boiler.

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