Hi,
having just replaced a heat exchanger on an ideal response 120 i now find when the burner lights it sounds "rougher" in operation with a wind type noise and occasionally there is a trumpeting type sound when the burner stops. The burner then cuts out and reignites with the same procedure.
The flue is unobstructed and sealed and system pressure is normal havent touched the gas side of the boiler other than to remove gas injector to the fan assembly for access,
any help much appreciated,
nige