Side Venting On my new boiler... Please help me!!?

I just replaced my 50+ year old boiler with a 92-98% efficient unit. We have had several boiler contractors come over to bid the job for us and most recommended side venting through our basement wall. I believe our older boiler vented out of the chimney, but I am not 100% sure on this. After the new boiler/hot water heater was installed and they tried it out, I started seeing a lot of smoke coming up the house, from the side vent under my sun room and living room. Unfortunately, their are a lot of windows in the exterior so this was very noticeable and the exhaust was coming in the house through the window. I did not expect this much exhaust coming from the vent. Because the HWH was also installed, we will be seeing this exhaust all summer in the back yard and will never be able to open a window in our living room or sun room. I'm am not sure what to do. If there is an extra flue that the old boiler vented out from, why would they not choose to do it the same way. I am very upset by this and did not expect this much exhaust to come from the side vent. Also, with our harsh winters, I am probably going to expect issues with the condensation from the side vent. I know this is up to code and probably standard, but I feel this will only bring us problems. I need advice... PLEASE! Thank you!