register noise

[Dutchie]

My problem is all of the heat registers in this house are situated 3/4 up the wall from the floor. When we bought it was all oil, furnace/water heater. Brought the gas in and changed appliances. I now have an 80 high Luxaire furnace, it works fine but with the higher volume of air when the fan kicks in it is very loud especially on the main floor. Wind noise coming from the registers. Short of moving the ductwork which is not an option as the basement is finished any thoughts for a noise reduction solution?

[Admin]

Do you have a model number? What's the square footage of your home?  I'm assuming you have a high efficiency 80,000 BTU furnace.  Is this wind noise coming from the supply or return air registers?

You probably have a PSC multi speed fan motor.  You could lower the heating and cooling speeds by moving wires on the control board.  You would have to check your temperature rise and drop to make sure the furnace and a/c will work ok.

Sounds like either an undersized return air or supply air in the ductwork.  Just for testing purposes you can remove the doors and manually push in the door switch.  Get the fan to start and see if you still have the noise when the blower door has been removed.  Don't leave the door off as a fix to the noise, whatever you do.

[Dutchie]

Luxaire GM9S0808 Upflow 80000 Btu High efficiency. The wife thinks we have 1300 - 1500 sq ft 2 bedrooms and a bath on the second floor. The noise is from the supply registers, the returns are in the floor and as I mentioned the supply's are 3/4 of the way up the wall. Checking the temp rise/drop is there an faq on this site for that? Thx for the quick reply this will be our third winter with this issue not a huge deal but as the weather gets colder the unit cycles more often kind of annoying.

J 

[Admin]

The furnace may be a little big for your house.  Did you try taking the blower door off and running the furnace?  If the noise stops then it's most likely a duct work sizing issue.

I would try lowering the heat and cool speeds.  The furnace rating plate will give you a temperature rise rating (ie: 35F-65F).  Run the furnace for 5 minutes and measure the temperature inside the return air and supply air plenum at the furnace.  The supply temperature minus the return temperature is your temperature rise.