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Boiler Noise 2 

List of noises 5:

Groaning noise 1
Groaning noise 2
High pitch noise 1
Howling noise 1
Moaning noise 1

Annoying groaning noise stopped by running a tap.
We had a couple of plumbers out to look at our 7 year old Vokera 80e boiler, they all said it was the expansion tank, so we had that replaced, and the noise continued.
We get good heating to the radiators and good water temperature (well, to the taps downstairs, the taps to the bath are mediocre).
The boiler powers up and just makes this groaning noise until a hot water tap is run, and then it stops the noise straight away. The pressure is in the right area (according to the manual) at 1.5bar. I have to say though, it does happen more when the boiler temperature is quite low, i.e. heating water within the system below 20degrees (usually first thing in the morning), as opposed to heating the water in an already warm system. The noise tends to travel through the entire system, so having the heating on timer for the morning is a big no, unless I need an extra alarm clock!
Any help would be much appreciated, I'm sick of plumbers who appear to have no more of a clue than I do!

The noise goes away until the next time the boiler fires up, you can literally turn the tap on, the noise goes away, and sometimes when it refried it didn't do it..., but eventually it would...
I did find another forum which mentioned something similar...
The fulcrum arm which triggers the micro switch for demand for water sometimes doesn't return correctly to the resting spot and actually vibrates in a mid position, generating the noises... at first I was dubious of this, as it does/did sound more like pressure building. But, they suggested some WD40 to the arm's pivot, and sure enough, I've not heard from it in about a week!
Now I've just got sort out the boiler going into lockout, it's the "lit sensor" not making proper contact to the logic board, if you wiggle it, it's fine... I think it's a dry joint on the contact, but it's a blooming sealed block where the contact reaches the circuit board. Grrr, non-user replaceable parts, great for the company, pants for end users.
My friend's 18 year old boiler makes a groaning noise whenever it cycles on. The noise stops once the boiler cycles off. I am wondering whether noise reducer gel would be beneficial in this situation.
As far as I understand it the noise reducer gel addresses the problem of "kittling" which, supposedly, sounds like a kettle boiling (surprisingly enough). I would not say this low-pitched groaning noise sounds much like a kettle, but it definitely emanates from the boiler itself rather than the associated pipe work or other fittings. Neither is it coming from the pump, because as I say, it is only apparent when the boiler is actually firing rather than just circulating the water.
So my question is, is the noise reducer gel likely to be worth the twenty odd quid?


This afternoon I drained down and refilled, adding 1 bottle of inhibitor and 1 bottle of noise reducer and incredibly the noise has stopped completely. I cannot believe the noise reducer can be directly responsible for the instant disappearance of the noise. I thought it was supposed to work like a discolor which I would have thought would take some time to have an effect.
My theory at the moment is that the drain down has dislodged some smeg lime scale that had accumulated in some crucial part of the system (causing the noise) and it has either been drained away or displaced to some area where it's not doing any harm. I can't really think of any other rational explanation.
High pitch noise in central heating system.
Our new central heating system is giving out a high pitch noise, which is driving our son mad. Using a Glow Worm boiler, when we simply have hot water on there is no problem but when the central heating comes on there is a high pitch noise, which is difficult to relate to any particular part of the system. The pump has a three-speed setting and the noise is worse at setting 3. We think setting 2 gives less noise, but is still there. Only on setting 1 does the noise vanish. We just have to sort this out before it drives us all crackers. Any help appreciated.

If it's a new system could just be air in the pump try bleeding it remember to top up the pressure in the system if it drops below 1 bar.
I have a 4 yr old Britony Combi Chaffoteaux & Maury wall mounted boiler.
This morning at 5.30 a.m. when heating cuts on it started howling/moaning at high pitch. So, I turned it off.
This evening I have turned it on and the problem is still there !!
HOT Water Only - it howls and pressure 0.7 bar.
HOT Water and hot tap over half on no Howl and pressure stable at 0.7 bar
Central Heating on (need it because flipping cold !!) and it Howls and pressure drops to 0.1 and still goes - howls a bit more high pitched I think ....
So, turned CH off. Any thoughts - and if so any ideas which knobs do what?

I found the valve that adds water and therefore pressure to the system - its now at 1.0 bar and makes no noise with water and CH on - great! - Hope its not leaking somewhere - will keep an eye on pressure!                                                  

List of noises 6:

Rumbling noise
High-pitched whine
Hissing noise
Whistling noise
Boiling noise
Howling noise 2

My central heating system and Protherm 80E Combi boiler seem to run fine until I draw hot water (if the heating is on). A few seconds later, a slow rumble starts in the boiler and builds to a high-pitched whine, which only stops when either the heating is turned off or I draw more hot water.
Having read some earlier posts on here, I've turned the pump speed down from 3 to 1. This has lessened the noise, but it's still there.
The heating is via 6 radiators, 4 have TRV's, the other 2 have basic flow taps. I've tried every combination of having these valves open/closed but it seems to have no effect on the noise.
Any suggestion please on what this could be and how I fix it?

It sounds like the seating on the diverter valve is chattering, not something you should attempt your self unless you are ultra confident.
A loud, steady, high-pitched whistle when alight, often audible from outside in the street, usually originates from the gas valve. Usually associated with the obsolete 'Ranco' brand gas valve and Potterton advice replacement of the valve, but other engineers report the problem can sometimes be fixed by adjusting the existing gas valve. Potterton advise replacement because adjustment needs special tools and getting it wrong can make the boiler dangerous. New gas valves are factory pre-set and need no adjustment after installation.
I've recently purchased my first home, (foreclosure), and it came with a hot water heat copper baseboard system. The boiler is a Burnham 4a Circa 1986, and it's not original.
Ever since we moved in it didn't seem to matter how hard I tried, or how long I flushed the zones, I couldn't get all of the air out of the system. There aren't any bleeder valves. I could hear the air bubbles going around and around, making the whole heating loop. This was annoying.
So, last week I installed an automatic air vent at the beginning of one of the zones. This eliminated all of the noisy air bubbles, and I'm amazed at how quiet hot water heat is!
However, now I've got a new noise I don't remember hearing before...
About 10 seconds after the boiler cycles on, a hissing/whistling starts. It sounds kinda like a tea pot on the stove starting to boil. It seems to be coming from the boiler. There is no visible steam from the outside. The sound lasts for about a minute and then it dies off. This is well before the burner on the boiler shuts off.
Is this noise normal? If not, what's the first thing I should check? Is it possible it's cracked or something and leaking steam into the chimney?
The temperature of the boiler seems to stay around 180 when it is operating, and the PSI is around 20 when the system is hot, 12 when it is cold.

I wouldn't worry too much about the steaming noise. It could be a bit of sludge in the base of the waterside, and water turning to steam under the mud until it's driven out.
You might turn off the auto water feed and keep an eye on the gage. If it drops when cold, then there might be a leak hidden somewhere.
The Boiler is approx 4 - 5 years old. When the boiler is working for heating, it starts making a noise like a boiling kettle after say five minutes of use. If I leave it like this, the boiler turns itself off for a while then fires back up it can go on like this for half hour or so before it finally stops working and a red LED appears on the front panel. I then after reset the boiler. The only way I can get the boiler to work without shutting itself down is to turn the temperature dial to minimum all the radiators do get warm but not hot in this setting. The Hot water works fine no problems at all.
This has been like this for over a week, it happened after I changed our kitchen radiator. I shut all radiators off and drained down the system changed one bit of pipe work (new radiator slightly longer than the old one). filled system back up via the filling loop open all radiators and bled them got pressure in system to just over 1 and now have this problem.

Well, gotta say a big thank you to everyone who contributed on this post, have had the boiler running in the auto position on the temperature dial for the past 2 hours and all seems good, no noises, no locking out, really warm in our house right now.
Well took the pump off and all pipes connected to it, pump was clean as a whistle and running free. The problem seems to be that the two large hoses coming from the heat exchanger were blocked with lots of rust deposits the longer of the two hoses was the worst. I cleaned said hoses and put all back together now working a treat. Unscrew the ntc to expel the air in heat exchanger.
A Valliant EcoMax Pro 18E' Condensing Boiler, installed 18 months back, has begun to make a horrendous howling noise when starting up from cold. Initially, HW is called for and there is no noise. However, half an hour later when CH is called for, the howling starts and continues for about five minutes. All is then ok until the next programmed period starts it up again. Valliant's Service Engineers have changed both Burner & Heat Exchanger without success and have given up (in spite of a 2yr warranty) blaming the water condition and suggest the system needs the inevitable 'power flush'. Before embarking on that, I wondered if anyone may have come across the problem and have other suggestions.

I have the exact same model boiler and have had the howling pretty much as you describe soon after the thing was installed. After giving up on the 'installer' who power flushed the system twice, I decided to attack it myself. Upon disconnecting the boiler from the heating circuit, I back flushed then flushed the boiler itself using the mains supply and got a fair amount of sludge out of it. Then I mains flushed the rest of the HW and CH circuits, connecting where the boiler was and isolating things as I went - again getting quite a bit of crud out. This was just before Christmas and I have had X400 in their since. I'm going to give it a couple more weeks and flush everything again and fit a Magnaclean.
Anyway, the howling has gone and all I have now is sounds like the fan combined with some faint kittling. If the kittling is still there when I re-flush I think I might try pouring some hot DS3 into the boiler when I have it disconnected and see what happens. Maybe the color change will give me a clue as to whether there was any lime scale?                                      

List of noises 7:

Howling noise 2
Buzzing noise 2 Buzzing noise 1
Whining noise
Moaning noise 2
Boom sound

At a friends house a strange and loud howling noise comes from the loft when running the hot water.
It takes a few minutes to start and will begin to stop when the tap is turned off.
Turning the cold water on in the bathroom only seems to stop it also the heating and water is run off a multipoint (I think). Any ideas on what it is and how to fix?

Change the ball valve, in large tank.
I have a Worcester Bosch Combi Boiler 28i RSF, it was installed Nov 02 accordingly to the service booklet.
I have been in the house for 3yrs and decided I would get it serviced, so following the service several months ago the timer switch pin 'broke' and although would still work for often fall off.
I sourced a replacement timer myself and fitted it without too much hassle about a month ago (casing slid off, 2 screws to allow the main console panel to rotate down exposing the back, and then four screws holding the back panel on). However, I struggled to get the 4th screw out so just about managed to remove the old timer and sneak in the new one, however at this point the plastic bit broke off that keeps the screw in place (left rear screw) however the backing panel was still tight.
Coincidental, after this, 50% of the time when I would use a hot tap and then finish using it, you could hear a fairly big noise from the boiler. But general running of the boiler for heating made no untoward noises.
Until last night when the boiler was buzzing constantly with the C/Heating, I could even hear it making the whining noise when I got home from the pub last night, outside, via the flu outlet. When the boiler is not being used, there are no noises. When I only use hot water, something switches on and at this point is makes a 'buzzing, whining noise constantly' until I switch the water off. Likewise with the heating, however if I have the heating on and then switch on a tap, there's a brief moment when 'it' makes a slightly different noise and then goes back to the original noise.
The noise seems to be coming from the Pump (it says Bosch on it) but obviously I cant be sure having no experience with boilers, any ideas?

It was indeed the fan that was knackered, there was still power going to it but it just failed to spin.
Bought a replacement today and had it fitted, it was quite badly rusted at the back and the backing plate was completely detached for the fan.
Looks like the knocking noise every time a tap was turned off may have been down to the fan knocking against the loose plate.
I have a `Chaffoteaux & Maury Britony Combi 80` combination boiler. Not sure how old it is (at least 5 years old as it came with the house and I have been here 4 and a half years). It has had a lot of problems with losing pressure over the years so I have called a heating engineer in on a number of occasions, then just over a year ago it lost hot water completely and had to have a new diverter valve (sorry, not totally sure of the terminology). The engineer also serviced it at the same time. In the summer of this year I lost hot water again and prior to this it had also been making a moaning noise from time to time. (The closest comparison I can think of is the Wookie in `Star Wars`) so I had another engineer in to sort it - I'm not sure what he did but he didn't have to replace any parts and everything was fine afterwards.
All was fine for a few months, then recently the moaning started again - occasionally at first, but now it happens whenever I run the hot water. There is also no pressure at all according to the gauge. I have tried adjusting the three valves sticking out underneath, but really don't know what I'm doing and one of them made the boiler start banging so I decided to leave it alone! I'm reluctant to call anyone out again as it's fine for a while then starts again, but the house is on the market so I don't want it to happen for the new owners (not for a few months anyway...). Any help would be greatly appreciated,

The boiler is probably moaning because its empty:
Sealed heating systems, as are almost always found with Combi boilers, need to have their pressure checked and topped up from time to time. In most cases the pressure gauge will be on the front of the boiler and should register 1.0 to 1.5 Bar.

Over time the pressure will fall. How quickly depends on how leaky the system is. Very small leaks often occur on radiator valve spindles, Automatic Air Vents (AAVs) and other components. Often you will not notice the leak since the small amount of water will evaporate.

Recharging the pressure once a year is probably normal, but once a month or more excessive. Every time fresh water is introduced, further scaling and corrosion may occur in the system, so you should not leave an excessively leaky system to continue.

To recharge the system pressure you need to locate the filling loop. This is usually a silver colored, flexible braided connection with a small valve at each end. Usually under the boiler or nearby, but sometimes incorporated into the boiler (Valliant Turbomax Plus and some Worcester for example).

The first two of these pictures show the older pattern of filling loop (still sold and fitted) , the one on the right the newer pattern which complies with water regulations. The mains connection in each case is to the valve with the handle (or the larger valve, where both have handles), the other end being the return pipe connection.
Having identified the filling loop, you need to work out what control valves there are. The first control valve will be nearest to the connection to the mains cold water pipe. This valve may incorporate a Double Check Valve (DCV) or be followed by it.

Then there will be the flexible connection which is usually left connected at each end (although in theory it should be disconnected - if yours is disconnected, connect by screwing swivel nut at the end). At the other end of the flexible connection (loop) will be a DCV and/or another control valve, then the connection to the return heating pipe.

The control valves may have plastic levers or screwdriver slots. In each case, they are on if the lever/slot is in-line with the valve (length ways) and off if the lever/slot is at right angles to the valve. There may also be a screwdriver slot on the DCV - do not unscrew this as water will be released.

If there are 2 control valves, practice turning each one separately (no water will flow unless both are open). To recharge, open the control valve(s). You will hear the water flowing and observe the rise in pressure on the pressure gauge. Close the valve slightly if it is filling too fast. When the gauge gets to 1.0 Bar or a little over, turn the valve(s) off.

Make sure that the valves are properly closed, preferably by disconnecting the filling loop to check that no water is flowing. Operate the boiler and check the pressure again. Any air in the boiler will vent and this may result in a drop in the pressure, requiring further topping up.

You may also need to vent air from the radiators, particularly those at the top of the system and near the boiler. When you do this system pressure will drop again, so top up again. After this the pressure should remain fairly stable, although a slight increase on heating up of system (and drop on cooling) is normal, as is a slight change when the pump operates.

2 days ago the boiler was cleaned. Now when it starts, it makes a much louder 'boom'. I guess it could be cleaner ignition. I have no clue obviously. It seems to 'start up' run a few seconds then ignite. Just sounds different than before.

I thought yesterday I smelled a bit of oil but just figured it was just burn off or something. Today I don't smell it at all. He said it was cleaner than he thought and the chimney was clean etc. no problems

So would a new nozzle 'fire' differently than an old one? I hate to call for service when I all I hear is 'a different boom' lol!

To complete the thread, had more boom and stink this week so today called the company and someone was here within the hour. He adjusted the mixture, took out the nozzle, and adjusted it too. Said he preferred the gap a bit tighter and measured it. Took multiple stack readings too and even said some older burners 'like a little soot' or something like that. I told him the other guy adjusted things until the paper was totally white.

Was just here a few min and I'm hoping all is well now. Was started and stopped about 5 times and sounded great.      

List of noises 8:

Popping noise
Sizzling noise

Rattling noise 1
Knocking noise
Grinding noise 3 Grinding noise 1, 2
Rattling noise 2

What would cause a popping or sizzling noise in my boiler?

A "hot spot" can be created by sediment accumulating in the bottom of the boiler sections which is typically the lowest point in the hydraulic heating system. The sediment acts as insulation and can be carried into the system by poor water quality and should filtered if necessary and corrected to a proper pH level of 7 to 8.5.
The popping sound that is being generated is water that turns into steam until it escapes back into the cooler water where it is rapidly cooled and creates a popping sound. Most of the time this can be repaired by having your service technician flush the system and if necessary use a boiler cleaner to help remove the sediment deposits.
The cheapest method to cleaning the boiler and system to prevent a reoccurrence of the noise problem is using the Fernox Heavy duty Restorer and Fernox DS-40 boiler discolor as outlined by Fernox, so preventing boiler replacement and re-plumbing.
Firstly, drain and flush the entire heating system with plain water until non-foaming. Circulate a 2% solution (2 Liters per ten radiators) of Fernox Heavy Duty Restorer in the whole central heating system either continuously for 48 hours or intermittently under normal load conditions for a week i.e. 7 days on a 6-hour heating cycle. Drain and flush the whole system until water is clear and to ensure flocculated sludge and cleaner are removed from the system. At least three complete changes of water are likely to be required. Were pipe-work is present below the drain-off points, I would recommend operating the pump for 10minutes between each flush, so ensuring any material remaining in the low points is diluted further. Secondly, to clean any baked on debris I would also do a separate boiler descale by isolating flow and return pipes to the heating circuit, or by closing the lock shield and wheel head valves to all radiators except one. Use a 2% solution (for typical domestic system, a restricted circuit on 2% DS-40, will require only half a 2Kg container) of Fernox DS-40. Allow this to circulate for 24 hours at 700C. Drain the system whilst still hot and flush with plain water.

I have a 6-year-old boiler, which has had many problems largely due to the regularly mentioned heat exchanger scale problems - now have a water softener and far fewer problems. A recent and new problem is a rattle that appeared to come from the main heat exchanger now changed and further investigation points to the region of the water manifold - pressure switch area. I recall someone mentioning a weak valve return spring as a possible cause of noise in these boilers but can't find the post/thread again!!!
Any help appreciated the MHE is new and the DWE is a descaled swop (I have 2 one on standby very hard water here).

If the diverter valve does not close fully (due to primary system carp building up on diverter pin) primary flow intended for the ch, spills through plate heat exchanger. It's going in the correct direction, but at reduced velocity, causing the nrv to rattle. When hot water is drawn, full flow of primary water through plate heat exchanger renders nrv silent or inaudible due to mains water noise.
I don't mean scratch all the chrome off pin, just remove deposits and re grease.
A few weeks ago I had observed a loud knocking noise at the boiler at firing and at the end of the heat cycle. Boiler was at 18 psi. The noise resonated throughout the entire house. After a few days, the knocking noise ceased, but was replaced by a grinding, rattling noise. This noise was not really present at the boiler, but rather at each radiator. The noise was present from firing through to the end of the heat cycle, but was not present at any other time. The noise also seemed louder at higher boiler temperatures. Boiler is at 15 psi.
I called in a technician who suspected lime in the boiler, and was going to contact the manufacturer (FP Industries) to determine a de-liming process. The boiler is of cast-iron make. I am just wondering how successful a de-liming process might be, and if the noise might be a result of any other problems (e.g. - scale in pipes)?

Yes, you can get your boiler de-limed. There are less-dangerous citric cleaners available to delime. It does have to take the boiler off-line for a long time to get the lime dissolved. Your boiler uses metal seals, so the process would be less damaging.
Scale in pipes is usually the same as lime in the boiler, excepting the hot surface of the boiler would make lime settle there quicker. Lime makes little 'caves' for water to get into near the metal the calcium and magnesium lime is sitting on. When the burner is on, the lime insulates the metal away from the water until the lime gets hot enough to boil the water in the cavity. Meanwhile the metal with less or no lime on it has already heated the water to a lower temperature; the trapped water has to get hotter to escape the cavity. When the cavity water turns to steam and escapes the cavity, it is cooled by the water, not steam, that is inside the boiler, so it collapses upon itself with a BANG. This process is called cavitation that has been known to destroy pipes and pumps. So, lime is not a good thing inside the boiler.

Now here's the important point. The manufacturer didn't put the lime there. The only way lime could come into the boiler was by filling it. Granted, that you have to fill the boiler ONCE on the first try. After that, there is no place to put more water. So why was there enough water in there to gather at least a fraction of an inch of lime? Why of course, the system was not SEALED. The plumber left a LEAK. Leaks kill boilers in a few years. One little drip a minute can fill a boiler with one-inch of lime on the bottom in a year. It is a boiler-killer.
Can you see why the manufacturer of the valve tells you on their written instructions to shut the hand valve to the Pressure Reducing Valve? It is NOT an 'automatic fill valve' it is better-named a 'BOILER-KILLER'.                           

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