So after doing a lot of research and finding a lot of great data on this site, I decided to go ahead with the contractor who quoted me $10k for a Triangle Tube (Trimax Solo) 110 with a 40 gallon TT indirect water heater (and all the pipes/pumps/everything in there). The only remaining question that I have is on how to mount the boiler to the wall.

The contractor is planning to mount the boiler right to the foundation wall, not use any type of plywood or anything behind it - does that make sense to anyone? I've only seen examples of where the boilers are mounted to some type of board, never to the bare wall.

Any thoughts?