Water Heaters - Venting Options for a Tankless Bosch Aquastar 250 SX

I really want to install a tankless hot water heater. I had chosen the Bosch AquaStar 250 SX.

Today I was told that I may not be able to install one as easily as I thought. The Bosch requires a stainless steel vent pipe which needs to be installed 36 inches away from any window and atleast 12 inches above grade. My contractor is also telling me that I may have a number of issues with that much heat coming out of the side of my house. He asked me to look into PVC vented systems.

My questions to you all;

1. Can I go straight up (2 floors) from my basement and vent the unit through the roof?

2. Do you know of any PVC venting systems for the Bosch?

3. Any other tankless systems out there that offer PVC venting options?

Any suggestions/recomendations are appreciated.

Thanks!!!

I have an Aquastar 240FX (which has recently been superceded by the 250) which I installed about 2 years ago. I used single wall stainless steel vent pipe which is what the installation manual calls for and I vented it horizonally. The distance clearances called for I believe are more to do with code compliance that something specific to this heater. Unless you have bushes or things that can catch fire very close to the vent you should not be concerned. I used the Aquastar vent kit which has an inner and outer pipe arragement to protect the framing from getting hot.

I'm not sure how PVC is going to reduce the heat of the vented gases coming out.

The US Distributer tech told both me and my plumber that the microswitch assembly (pilotless electric ignitition) is going to fail every 2-3 years. I now have a $950 wall decoration.