Fog Horn Noise From Mod Con

Derheatmeister

I have Heard this on some of my TT installs at 10k feet,the only way we are able to get rid of this is to adjust the O2 to i think 9.4 and yes you are trading off some efficiency

what brand are you talking about?

Magnehelic

Fog Horn Noise From Mod Con

Hi Guys!

Snowing here again in Spokane, WA (54" so far this year)Hey......we are the factory service and start-up provider for a mod-con manufacturer, and we have experienced on 3 or 4 installs (none that were ours yet thank God)the boilers making a fog horn (LOUD!) noise, at sometimes just start up (on one install) and other installs at a certain modulation percentage consistently. (two mod points on one install). One of my techs experienced this when one of the boilers was at 94%, so he made 91% the highest firing rate for the boiler. Other than that, we have not been able to address the others. Any idears?

Thanks

Don in Spokaloo

Xc8p2dC

Nat Gas? or

Some nat gas units made the Gas Valve GROAN, taken out by adjustment>> if so, check WC pressure to be in spec first

Rick_92

Fog Horn Noise

Please Be Careful!!

First of all, turn off the gas and shut off the electricity to the boiler.

A loud fog horn noise is usually an indication that a huge ship might be heading your way and about to strike the building.

Make sure everyone has a life preserver close by. Do not, by any means, sleep with any unsecured pictures above your head. Upon impact they could be knocked off the wall and hurt you.

Wait till the fog clears and then get up on the roof and look all around the building. If there are no big ships in sight you will be OK. At that point turn everything back on and if you still hear the noise get a good set of sound- deadening headphones. I prefer Bose.

Magnehelic

Fog Horn

Rick,

We have experienced this on both gas AND LP. We always check gas pressure and combustion analysis. This appears to be a resonance when perfect conditions exist between fuel/air, and fan rpms on neg reg.

Don

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Mark Eatherton

Ran in to this yesterday...

on an early Knight. If you disconnect the combustion air and the honking stops, you need to drill a 1/4" hole, in the combustion air intake pipe, inside of the boiler vestibule.

No more honking.

ME

Mark Custis

Great Minds

I have done that.

Unknown

Delta T across the boiler?

tim smith

Maybe some debris on air inlet or orifice. We have experienced

this on some jobs. My guess is your the factory start co. for Lochinvar?? Take a close look.

Al Gregory_3

I just helped my nephew install a loch the other day and had the same thing happen. I asked about it at the supply house and got strange looks like they never heard of it before.

Scott OB

Lochinvar Knight

I have a KBL-105 that was "honking".Called tech support at Lochinvar and they sent me a stainless steel strap that goes across the top of the heat exchanger.It puts pressure on the heat exchanger and it is suppose to stop harmonic noise.Mine stills make a little honking sometimes.I think I will drill the hole also.
Scott

Unknown

Incredible!

Magnehelic

Fog Horn Noise

Guys,

We have experienced this on both Munchkins and Loch, gas and LP. We almost always set up our boilers at 25 degree delta. In speaking to one of my go to guys a tthe local rep, he told us to try these two things. Will let you know.

1) Duct tape over 1/3 of the vent outlet. If noise goes away, install 3/2 reducer (or 4/3 or 5/4 whichever applies). If noise does not go away perform the following:
2) With a Combustion Analyzer hooked up and running, find sticker on gas valve that says "do not adjust" and remove. Turn gas valve adjustment screw (the one under the sticker you just removed) 1/16" clockwise, making sure via combustion analyzer that you have not thrown the fuel/air adjustment out of whack. Always a good idea to mark position before moving, in case you need to start over. According to my go to guy.....this remedied the two systems that he ran into, and neither adjustment made a noticeable difference on the analyzer.

Don

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Unknown

Makes more sense than strapping it down. Thanks

I wonder if putting a reducer on the vent terminal would have a similar effect. Balancing can be a problem when you're allowed 80ft.and only use 5.

[Deleted User]

Drill a hole!

I have a KBn 210 doing the same thing. I wll drill a hole tomorrow and see if that does it.Thanks

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GoCat

Fog horn

My Lochinvar Knight KBN-80 did this when I first installed it. Seemed to be a function of too short a intake. The unit was set about 2 feet from the exerior wall, and both the intake and exhaust were a straight shot to the outside. The fix was to put a couple 90 elbows in the intake. Quite as a mouse, now.

tim smith

Don, call heat transfer tech support and Lochinvar tech support

directly. They will have a direct answer for you. Talk to I think it's greg at heat transfer, really good guy and has heard it all. They are always the 1st line of defense for these problems as they have heard it all. Good luck.

Charlie from wmass

I had this on a pair of HB smith boilers it was due to the burners not be quite well tuned, I got a new analyzer and the sound went away. I guess for me it was a call to up grade my tools.