The unit pipes outdoors using PVC (not foam core) DO NOT INSTALL FOAM CORE it could kill you if you do not listen. If the words on the pipe say FOAM or CORE do not use it.
The vent has a length limitation of how many feet you can run it, the 3" can run longer as it's larger diameter.
Every elbow and 45 elbow will reduce the feet please refer to the directions for the details on how far you can run this.
I went about 15 feet with mine using 1 elbow so I was fine but the max normal is 50 feet with 2" on a 100K boiler. 100 feet with 3" piping.
You want to install your outdoor weather sensor on the NORTH side of your home away from the sun rays to get a correct reading. Use your iphone built in compass to detect north. This will allow you to save money when it's warmer outside. I won't get into technical details but it is a condensing boiler so it can reuse gases in the vent when it condenses at those temps so you save money and waste less natural gas.
I found that the boiler didn't like the GFI and it would hit a ground fault because of the way the boiler works drawing power at times higher then others. I ended up removing it. Better to use a whole home surge protection or a panel breaker with a built in surge protection.
Do this now before you fire up, just pull the bottom of the pipe connector off and fill it with water then reattach it.