aosmith gw/gb series boilers

kevin mulligan

have 8 of these on a jobsite. all are piped as secondarys to the primary loop. every one of them has a harmonic sound to it when outlet temp gets around 170 dergrees and above. td thru boiler is 20 degrees. if flow is increased to drop td down to 12 to 15 degrees,it quiets down to where it is almost inaudible.factory rep has been working at this site for over a year. secondary pumps are on outlet of boiler pumping away from boiler back into primary instedof pumping away from primary into boiler inlet.he said this was the reason for the noise,that the water was steaming of in boiler.he repiped the pump on one of the boilersso that it pumps away from the primary loop into the boiler inlet,but this boiler makes the same harmonics as the others. has anyone run into this with aosmith or any similar style boiler? i have not come across this problem before this call.it appears to be flow related,but the rep told the customer that below the 20 degree td would wear out boiler prematurely due to erosion.any help would be appreciated. thanks.

Einsiedler

age, health

if not a new install and the noise was not there when commisioned, I would check water. Boiler(s) may need cleaning.

Howling like a wolf is usually dirty tubes in my experience.

good luck!
EIN

hr

It doesn't take much

scale or deposits on copper tubes to cause a big drop in heat transfer and related noises. A chemical treatment may help. Worse case you have to remove the headers and use a cleaning brush.

Sometimes increasing fill pressure will quiet them down.

For efficiency, and safety sake it is best to clean the HX and pump them according to manufactures specs. The usually shop acceptable delta T and pump flow and pressure drops on the installation charts.

Don;t be tempted to adjust or bypass flow switches, The two problems often run concurrently, (noise and failure to prove flow switches)

hot rod



To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Contractor"