how do I stop a condensing boiler overflow from freezing?

Use electrical Isotape connected via a frost state

Stuart
January 2011

Our boiler overflow has frozen twice in a few days. The second time I tried the usual pouring warm water on the pipe and it didnt work. Phoned my plumber who told me that nearly every call he is getting was about condensing overflows freezing.
He suggested that I cut off the overflow pipe, did that and found the overflow pipe free of ice. Still the boiler did not work. The plumber suggested using a long screwdriver and probe the overflow pipe into the wall bingo I struck ice. The pipe was blocked nine inches into the wall. Used a hairdryer and the ice melted and we were soon able to restore the heating. My plumber is going to reroute the overflow pipe.

Barry
December 2010

The wire is called trace heating and works off a thermostat. The wire is cable tied to the pipe and then insulation put over the top of this. The thermostat is out side so when the temp drops to around 5 degrees the wire starts to heat reducing the risk of freezing!! Excellent bit of gear.

mouser
December 2010

british gas say they can fix a frozen vent pipe on my con boiler for £199 they will lag the pipe and put a wire thro it .understand the lagging but what,s the wire for

p.c
December 2010

Got the same problem in my overflow in the last cold snap, I have re-routed the overflow inside the loft with an exit out of the soffit which then goes straight down vertically to the guttering overflow pipe, I have used coiled plastic pipe so that there's no joints to drip inside and lagged it with one inch thick high density pipe lagging all the way from under the roof to the pipe. it has'nt frozen and this is on a north facing wall.

Andy
December 2010

We had our pipe cut and draining out freely - worked last year, but this year it is still freezing before it gets out of the cut bit of pipe - icicles coming out of the end of the pipe and pipe full of ice.

As our boiler is in the loft the pipe is high up so climbing on the roof with kettles of hot water not a realistic option.

Presumably some serious lagging is the answer but wonder why this wasn;t done as installation

VB
December 2010

I have also experienced the same problem with the condensation overflow pipe and BG came last Friday and cut my pipe. The engineer then poured a kettle of boiling water to unfreeze the rest of the remaining pipe. The boiler now works with the bit of the remaining pipe dribbling out onto the wall. The BG engineer said to call him back in a fortnight or after the current cold snap and he will come back and put the pipe (32mm diameter) back on.

What I think I would like to look for, is a permanent solution to stop the freezing occuring in the first place.

Jeremy
January 2010

you could up size the pipe, eg, from 3/4 inch to 1 1/4 or insulate the pipe with pipe lagging, hope this helps, also make sure there is a good fall from the boiler to the drain no dips in the pipe where water can collect,

hudds gas
January 2010