On 19/12/2009 15:48 cynic wrote:

We had very severe frost last night so I enquired if there was an ice
plug in the condensate outlet. Neighbour got ladder out to look and it
turned out there was. Soon neighbour had kettle out and a warm house
soon after.

Thanks for posting this. Seriously pleased you did!

Heating came on this morning and then turned off unexpectedly. Checked
the boiler, saw it was locked out, reset it, it started but sounded as
though it was full of air from the gurgling sound. Looked outside to
check the plume, no plume and the gurgling was even louder, as though
the fan was blowing through water rather than the pump trying to pump air.

Remembered this thread, got the kettle out, and poured it all over the
external elbow from the condensate drain pipe. The boiler has now restarted.

Management had placed a tile over the drain cover into which the
condensate pipe empties after a low level near horizontal run. Looks
like the last time it flowed it froze at the end of the pipe as it
couldn't fall and clear the end. The ice plug just worked its way back
along the pipe until the whole lot blocked.

There is an air gap between the elbow that exits the wall and the wider
vertical section of pipe but it just froze backwards and filled the gap
before working even further backwards and blocking the pipe completely.

Can now get back to wallpapering the bedroom with the paste table in the
garage with a wide open door and the temperature sub-zero...

--
F