“In cold weather, the pipe that takes waste water from the back of the condensing boiler-which isn’t there in a normal boiler-freezes solid, shutting down the system and in many cases causing permanent damage.”
I don’t know what brand boilers these are or how they are installing them, but we install and work on condensing boilers all the time and there is no problem with anything freezing. If they are piping the condensate to the freezing outside, well DUH, it can freeze. You are not to pipe the condensate or any relief piping directly to the outside.
“the government initiated a program which paid homeowners £400 towards the purchase and installation of the new boilers. “
We had something like this years ago called Electric Thermal Storage”. It was pushed by the utility with huge rebates. It was a complete disaster. I doubt if any of the systems are still in use.
“One of the bi-products of the condensation process is the creation of acidic water vapor from the dissolved nitrogen and sulfur oxides which corrode the delicate system components”
Improper installation again. The condensate must be collected from the flue piping or unit and disposed of properly. No corrosion. What “delicate” components. “Delicate” is not a term we use in the HVAC business.