Gas and Oil Home Heating Furnaces - Reducing power vent vibration

Greetings - I have a power vented furnace that is noisy. The noise is largely from vibration into the wall, which I can feel in the living room above the furnace. When the tech was out at the house for the annual tune up, he cleaned the fan and such inside the vent and checked for roundness and said it looked pretty good to him - but the noise was a little worse after he left! He said that he, and most HVAC folks, do not like the power venters...

This is actually my second house with a noisy power vent. At the first house, I was able to reduce the vibration/noise to acceptable levels with rubber grommets and such attached between the chimney pipe and the joists. In the new house, though, the chimney pipe is square right after the power venter, and shoved up between the floor joists. I've tried jamming things between the square part of the exhaust and the floor joists, but that solution is always temporary. When trying to feel around for the source of the vibration, things dont feel that bad in the joists and such - but the exterior wall.

There is no room to see anything from the inside, so I was thinking of taking things off from the outside to see if there was anywhere I could 'rubberize' to reduce the vibration going into the wall.

Thanks for reading all of this, and I'm glad you are still with me. AFTER ALL THAT, my questions are:

1 - is there any special sort of material I should be using? I'm assuming that if metal is touching wood that it doesnt get too hot to worry about fire, but I'm assuming that :)

2 - other than getting rid of the power vent, any other ideas?

replace the blower wheel, best done professionally so that you are sure that there will be no fumes leaked in to your house. shimming can create a fire hazard, isolation will work until the rubber tears. either way, an out of balance wheel will shake itself apart and prevent firing the burner due to saftey interlocks. if the interlocks are not working, a broken wheel WILL result in fumes backing up in to the house with attendant CO poisoning hazards and soot damage. a bad wheel will also wear out the motor... best repair is to replace the motor and wheel together, every 3 to 5 years is not unusual; more frequent near salt water. if the unit was worse after servicing, ask the contractor to come back and make good on his work...

the only ways to entirely eliminate this problem is to go direct vent with a condensing gas appliance, direct vent oil boiler (has its own problems), install a chimney, burn coal...

Thank you very much for the speedy reply! If replacing this thing every 3-5 years is not uncommon, might it be worthwhile to put in a chimney? I know little about it...the tech that came mentioned it is possible to replace with stainless steel chimney. my preliminary research indicates it's about 175 bucks for a two foot section of the correct pipe...it's a two story house, so that'd be a couple thousand dollars.

Are these power vents more efficient or something? Would my current furnace still work with a different venting system?

Again, thank you for your response and I will do as you suggest, but it just got me thinking!

I have heard from PV companies Fields and Tjurneland that if the wheel is not cleaned one year then it should not be cleaned at all for the rest of it's life. I guess if it is missed a year then the following year one would not be able to clean it completley enough so that it is true.

A chimney if best for venting but not always an option.
IMO, I like to see for venting a chimney, PV, then direct vent.

thank you! I'm leaning towards a chimney if it I can afford it this year!