This ¾” pipe is passing through the wall ‘horizontally’ and because of this, the water lying in this section of pipe was prone to freezing up in cold weather. This, in turn causes the boiler to ‘lock out’!
A larger (1 ¼” pipe) was installed; this penetrated the wall at a ‘downhill’ angle to keep the condensate water constantly ‘falling’ as it leaves the boiler and heads towards the drain. Note: the access cap on the top end of the tee piece.
Finally, “Armaflex” external grade pipe insulation is fitted to the pipe for a “belt ‘n braces” approach. This type of insulation is resistant to water ingress and is also resistant to UV rays which can cause standard insulation material to break down and become brittle and porous.