Noted, ecomodded.
@ Steve: I cannot (and am reluctant) to convert this boiler exhaust (miniheat by allied engineering, a local company) into power exhaust type.
Like I said before: (a) if I can get the exhaust pipe hot enough for the updraft to maintain the pipe's inner temperature, it should be of no problem); (b) once I have my Vanmar HRV installed, I'm gonna slightly tweak it into positive pressure (just by a couple of %), this should reduce the possibility of possible backdrafting due to extreme pipe temp (exhaust not hot enough to rise up along the cold pipe).
Thanks folks.
Q.
http://alliedboilers.com/products/mini-gas-boiler/