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UK diy (uk.d-i-y) For the discussion of all topics related to diy (do-it-yourself) in the UK. All levels of experience and proficency are welcome to join in to ask questions or offer solutions. |
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#1
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Noisy bolier flue
I have recently had an oil-fired CH boiler installed in an outhouse
adjacent to the house. The flue runs vertically up and thru' the roof about 12 feet or so high. Unfortunately, it's very noisy. It seems that the boiler's fan and the burner resonate with the flue so that it amplifies the noise to the discomfort of our reasonable neighbours. It emits a loud low rumble which is a tad annoying first thing in the morning. It is an exceptionally quiet location so the noise can be heard a long way off. I am wondering if wrapping the flue with a layer of something which won't catch fire such as loft insulation glass wool would help damp the sound. The flue gets quite hot so whatever I do has to use something that won't burn. Has anyone had this problem? Solutions? EP |
#2
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Noisy bolier flue
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#3
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Noisy bolier flue
The flue goes up thru' a corrogated roof but I'm pretty sure that it
isn't the roof that's the problem. It really is the 200mm (or so) diameter flue that's resonating. So it needs damping, EP |
#4
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Noisy bolier flue
wrote in message oups.com... The flue goes up thru' a corrogated roof but I'm pretty sure that it isn't the roof that's the problem. It really is the 200mm (or so) diameter flue that's resonating. So it needs damping, EP Your options are to:- (a) change the length of the flue to alter its resonant frequency (b) coat the flue in sound absorbent material to damp the vibrations (c) Add mass to the flue to change ( lower ) the resonant frequency away from whatever is exciting it and lower the amplitude. (d) Stiffen the flue to raise the resonant frequency above whatever is causing it. I am assuming it is the flue vibrating, and that the noise is not caused by the flue acting like an organ pipe. If that were true, the solutions would be different. If you lag the pipe, that will both increase its mass and ( if you use high-density rockwool perhaps ) damp it too. Changing the length of the flue would be difficult and no guarantee of success, and stiffening it might only be a little easier. Andy. |
#5
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Noisy bolier flue
wrote in message ups.com... I have recently had an oil-fired CH boiler installed in an outhouse adjacent to the house. The flue runs vertically up and thru' the roof about 12 feet or so high. Unfortunately, it's very noisy. It seems that the boiler's fan and the burner resonate with the flue so that it amplifies the noise to the discomfort of our reasonable neighbours. It emits a loud low rumble which is a tad annoying first thing in the morning. It is an exceptionally quiet location so the noise can be heard a long way off. I am wondering if wrapping the flue with a layer of something which won't catch fire such as loft insulation glass wool would help damp the sound. The flue gets quite hot so whatever I do has to use something that won't burn. Has anyone had this problem? Solutions? EP PS:, A pipe 12 feet long could expect to have a fundamental resonant frequency of 45Hz, ( half a wave length ) so it might indeed be acting as an organ pipe. If all the sound is coming out of the open end, as opposed to being emitted by the pipe itself, I can only imaging that there is some sort of problem with the way the combustion chamber is interacting with the length of pipe - a tricky one to solve, I can only imagine lengthening the pipe or having some kind of muffler on the end working. If you have a few feet of similar pipe and can stick it on the top, if the noise changes pitch that'll be a clue. Andy |
#6
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Noisy bolier flue
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#7
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Noisy bolier flue
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#8
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Noisy bolier flue
We were somewhere around Barstow, on the edge of the desert, when the
drugs began to take hold. I remember saying something like: The flue goes up thru' a corrogated roof but I'm pretty sure that it isn't the roof that's the problem. It really is the 200mm (or so) diameter flue that's resonating. So it needs damping, Are you sure the burner isn't pulsating? A common type of fault is mis-matched flue and burner settings causing a pulsating flame and sounds like a low rumble. Betcha the installer didn't set it up right. Similar thing can happen if the burner is running on diesel instead of kerosene - check the fuel. -- Dave |
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