Condensate pipe

Can u post a photo of the pipe work you are explaining?

 

It sounds like you have a leak. Maybe a solvent weld wasn't done correctly. You'd need to pour some water in it on the inside and see where it's coming out. Alternatively just rip out the old pipe and start afresh with something continuous like a ribbed flexible hose. That way you know it can't be leaking in a joint inside the wall.

 

The condensate pipe is connected to the back of your boiler and its purpose is to carry condensate from the boiler flu either into a waste pipe or to the outside of the house.
Most condensate pipes are made out of 20mm diameter rigid PVC pipe joined together with couplings and solvent-based welding gel.
Many of the couplings are poorly implemented and virtually untested at the time of installation, so problems are usually only noticed long after the heating engineer has left.
When temperatures drop below zero for long periods, the condensate drips in the pipe can freeze and continue freezing until the whole pipe becomes blocked by a plug of ice, and the liquid condensate backs up behind the ice plug. In cases like this, some poorly made couplings suddenly find liquid condensate sitting for long periods where under normal non-freezing conditions it would just flow past the poorly made coupling with minimal leakage, and these leaks then become more evident.
My suggestion above was to rip out the old pipe system and replace it with a 20mm ribbed flexible pipe that is long enough to do the whole journey without any couplings and flexible enough to bend around corners. Anyone who can route and bend a hosepipe can do this, so no need to call in a plumber or heating engineer just for that.
Any parts of the condensate pipe that are exposed to outside temps should be insulated to reduce the risk of the condensate freezing in the pipe. Any thick wall pipe insulation intended for 22mm pipes should be fine.

 

If u can work out how to put a pic up it would really help and a pic of inside where the pipe goes through the wall. Most likely a leak as said above, I have found condense joints even when solvent welded quite often leak after time or become brittle.

 

First thing I would do is dry all the pipes with some tissue, then look for a leak after the boiler has been going for a while.
The other thing is does the condensate pipe come out of the wall with a bend on down into the waste pipe or is the condense pipe just cut off as it comes through the wall and left to drip in the pipe? Sometimes if it’s cut off like this the drips will track back down the pipe so u need to put a bend and piece of pipe on it that goes into the waste pipe.