Possibly one for oilman !!! have a rielo 40 63b oil fired boiler. It had a balanced flue that turns 90 and exits thru the wall. my prob is that it smells my kitchen out so i moved it outside to a purpose built shed. it now smells my back yard out. Can i put a vertical flue on it as i am told that it does not need a balanced flue as it draws its air in from bottom of boiler please help