Well this is a new one for me looking for ideas

Charlie from wmass

I have a noise complaint with an Independence power vented boiler. They say it is much louder than their old HB Smith oil boiler. Yes combustion is set and checked. the blower fan is what they are complaining about. I used the Burnham because the chimney was shot and the home owners wanted to switch to gas. The vent pipe is with in a foot of maximum run but still under maximum. I am thinking it is resonance from the hangers to the floor joist. Ceiling above unit is not insulated. Boiler is now 2 feet closer to stair well than old unit.

Jamie Hall

Couple of thoughts...

Is this a modcon? (you see how dumb I really am, Charles!)  I ask, because if the vent temperature is low enough, could you put a short section of some flexible duct in there?



But you might remember that I mentioned that I had had a noise problem from the oil pumps on my burners -- the oil lines were strapped tight to the pipes, and telegraphed that sound everywhere in the house.  Fixed it by isolating them with foam.  Seems like your idea regarding the noise telegraphing from the vent through the hangers to the floor might be right on the money.  So... is there a way to isolate those hangers, such as with a heavy short bungee or something like that?  Strong enough to hold the vent in position (of course!) but a little flexy, to reduce the sound transmission?  (Kind of thing, in a way, that is used on cars to isolate the exhaust system from the body).  Only thing I can think of, off hand.



By the way -- Cedric II is doing fine so far, and it's been jolly cold.  Seems to be using a good bit less oil to do it, too -- somewhat to my surprise (but I'm not complaining!)

Charlie from wmass

Glad to here Cedric II is doing well

I fully expected the oil company would be less of a visitor. If you could guess on numbers I would appreciate hearing them. I am thinking rubber washers at the attachment points for the hangers but wanted to see if those who installed more of the powerventers had any ideas. This is a steam boiler so not a mod-con. The venting is stainless steel.

I did post a photo concerning the equalizer and the vent it has listed is a bit larger than a Gorton #2 I was hoping you caught that post.

Heres to warm and happy holidays!

Rod

Noise

Hi Charlie - Those odd harmonics are hard to chase down. When it's running (making noise) feel for vibrations.  Vibrations = noise

and with the long pipe you may have created a large musical instrument. As Jamie suggested you might check the hangers. Loosen /remove the hangers and temporarily support it the vent pipe with rope just to see if that was the problem. We had something similar with some hydraulic pipes and ended up hanging them (the hangers)  with some 1/16 inch stainless wire rope. (We got that and some nylon shoulder bushings (to isolate the attachment bolts) from Mc Master Carr) I was reminded of this when I read Gerry Gill's description of his new system. He suspended the fin units with wire to cut down expansion noise. Try the rope as it will a least prove /eliminate the hangers as a problem. Harmonic noise problems are a real pain!

- Rod

Jamie Hall

The numbers

so far -- I've only had two tank fills, and that's the only real gauge I have -- are enough better that I don't quite trust them!  But at least the 16% or so we cut the firing rate.  Couple of more fills I'll have better data, and get that to you.



Rubber washers just might do it -- just so there is no direct metal transmission from the hanger to the beam...

crash2009

Here is an idea.

Don't know if it will work.  Silicone gel mounts screwed into the floor joist.  Looks like a regular 3/8" ready rod could be attached to it. 

http://www.vibrationmounts.com/video/index.htm

Polycarp

washers

Just remember that you will need those washers on both sides of the hanger.  The hanger can transmit vibration through the screw/bolt/nail head up the screw/bolt/nail shaft and into the joist as well.  So, one washer between the hanger and the joist, one between the hanger and the screw/bolt/nail head.