Delta Temp boiler replacement

Charlie Richmond

I have a 40000 BTU compact condensing Delta Temp (Canadian product made in the mid 90s) boiler which uses 2" plastic pipe as a flue and it is working pretty well but has not been particularly reliable lately. Has anyone here replaced these units and, if so, what do you recommend?
The closest thing I've found so far (in terms of size and capacity) is a Viessmann unit called the Vitodens 2000 but it seems to require a larger flue. What do people think about this unit? Does it have a fan to push the combustion gases out the flue?

My flue pipe is very short but runs through a restricted space (short distance inside a wall) and it would be very difficult to enlarge/retrofit it. The technical pdf for the Vitodens indicates it can accept a very long flue run and the flue temperature is very low so I feel this may be no problem at all.

Here's the web page for the Viessmann unit:
http://www.viessmann.ca/Pages/Products/Wall/Vitodens200/Page-1/index.html

Thanks!
Charlie