Hi, We have a Pentair Mastertemp 400HD pool heater. It appears that the noise is primarily coming from the exhaust when the booster kicks in every minute or so. The loud rumbling and gangling sound occurs for 2-6 seconds every 1-2 minutes. The noise level is in excess of 100dB. It resonates through our building and the neighbours which is quite annoying. Does anyone have any advice?