I installed a TT PS 60 in fall OF 2011 just as the heating season finished it started to make a howling noise upon cold start-up. When the customer fired it up for this season it is still doing it. I finally had a chance to closely look at it. It only lasts for about 20-30 seconds, I was thinking that the air supply pipe to the blower was the right length to start resonating, I removed it and still does it. When it stopped howling, I put my fingers over the blower hole at the venturi and it would howl until I removed my fingers, then quiet. Has anybody ran into this, if so what did you do to fix the problem. I thought I'd check with you guys first before going to tech support at TT. Thanks for your help.
Rich Davis 3-M's
We had numerous problems of this sort last year with several TT boilers. The gas valve, MCBA board and air supply pipe were replaced and the combustion was set richer to solve the problem. Sometimes you can fix this issue by talking to tech services with a combustion analyzer on the appliance. They'll give you the parameters for both low and high fire rates.