Insulating a condensate pipe

Min · 30 Nov 2018

Hi folks

I've read the other threads about insulating a condensate pipe that runs outside, and opinions seem to vary between 'it won't freeze' to 'use a trace heating'.

Last two winters, the condensate appeared not to freeze, ie no problems with the boiler. But the foam insulation has worn away almost to nothing in places. (Climaflex website does say "It can also be used externally, although it will degrade faster than normal in sunlight")

What do you think? Do I need to insulate the pipe? If so, is Armaflex more resilient? And what thickness wall do you recommend (it seems to be in 9mm, 19mm and 25mm)?

Over a 4m run, the 22mm condensate pipe drops about 300mm, then drops vertically to a drain for the last 1.2m.

Thanks

Mary

Ian H · 30 Nov 2018

Can you reroute it inside?

Min · 30 Nov 2018

With difficulty as boiler is right up against outside wall

pete50 · 30 Nov 2018

I can 100% assure you, in spite of what this lot will tell you, that a condensate pipe will freeze solid if the weather is cold enough. The "tradesmen" who fitted my boiler a couple of years ago couldn't be bothered to insulate mine. It froze solid. called out BG who removed the elbow where it comes out of the wall to allow the condensate from the boiler to flow. This was a temporary measure they said. I ended up putting that rubbish foam rubber stuff around mine and it has been okay since.

Min · 30 Nov 2018

Thanks Pete50, out of interest, what were the symptoms it had frozen?

bernardgreen · 30 Nov 2018

Insulation will not prevent freezing, it merely delays freezing. In most cases the delay is longer than the cold spell.

If freezing is possible then trace heating and insulation is advisable.

Using a pre-installed pipe within a pipe can be effective in thawing out a frozen drain / overflow pipe. The inside of the inner pipe must be kept dry before use and then dried after use if hot water is used. Warn air ( from a hair drier or warm air gun ) from either end is slower to thaw the pipe than hot water but more convenient. Beware water from melting ice getting onto the electrics

No reason why in theory it would not also work for high risk condensate pipework. But regulations might outlaw it.

banjodeano · 30 Nov 2018

Min said:
Thanks Pete50, out of interest, what were the symptoms it had frozen?

I came home from a weekend away, i left the heating on a low setting as the house was a very old and a cold one, when i got home my kitchen floor was covered in water, the external condensate pipe had frozen and the water backed up, the condensate pipe joint under the boiler leaked and allowed the water to come out and drip onto the worktop then the floor, the pipe outside had foam lagging on and it and had a decent drop as well, but it still froze

breadnbutter · 30 Nov 2018

get a worcester condensure fitted , if you got room below boiler, and it should be 32 mm external pipe , what lagging does is protect the pipe from wind chill, its normally the wind chill coupled whith the - 5 and below spikes of cold, that freezes most condense pipes.
condensate pipe should be fitted by a registered gas installer, as it is part of the flue system.

Min · 30 Nov 2018

Thank you folks for the replies.
I think a CondenseSure plus 32mm ext pipe is the way to go for me. Will get the registered installer back in.
Many thanks
Mary

bernardgreen · 30 Nov 2018

Wind Chill related to how cold a person feels and does not apply to the cooling of a dry object.

Assume the air temperature is 0°C
A person standing in a 15 MPH wind wlll typically feel it as if it was still air at minus 6°C , at 30 MPH the felt temperature is typically minus 8°C
( The actual felt temperature will vary from person to person due to various biological factors )

A dry object will be cooled to 0°C and no colder irrespective of the wind speed.

A wet object may be cooled to be below 0°C due to cooling by evaporation in the wind but when dry the object will ( eventually ) return to the air temperature of 0°C

breadnbutter · 30 Nov 2018

bernardgreen said:
Wind Chill related to how cold a person feels and does not apply to the cooling of a dry object.

Assume the air temperature is 0°C
A person standing in a 15 MPH wind wlll typically feel it as if it was still air at minus 6°C , at 30 MPH the felt temperature is typically minus 8°C
( The actual felt temperature will vary from person to person due to various biological factors )

A dry object will be cooled to 0°C and no colder irrespective of the wind speed.

A wet object may be cooled to be below 0°C due to cooling by evaporation in the wind but when dry the object will ( eventually ) return to the air temperature of 0°C

a wind chill speeds up the freezing process, it does not make it more cold. SO protecting it from wind chill stops it freezing faster than it would.

to add, a trap that drips out condense rather than by syphonic action, with 21.5 condense outside with a wind chill will freeze faster, because the pipe is continuously wet. the reason for 32mm pipe is not that it wont eventually freeze, but slows down the chance of a total wall of ice, before milder weather arrives, but if you got a syphonic trap, 32mm pipe lagged, and heated condensate, your going to survive.

unless you live in the middle of Siberia.

Min · 30 Nov 2018

Thanks breadnbutter.
I get it that 32mm pipe will take longer to freeze up inside than a 22mm one, and maybe the cold smap will be over before that happens.
But isn't the advantage of the trap that it holds the water in the trap which is being warmed by the flow, and that it discharges not drip by drip, bit in a gush of water, which helps the water stay warm as it travels down the pipe?

breadnbutter · 30 Nov 2018

Min said:
Thanks breadnbutter.
I get it that 32mm pipe will take longer to freeze up inside than a 22mm one, and maybe the cold smap will be over before that happens.
But isn't the advantage of the trap that it holds the water in the trap which is being warmed by the flow, and that it discharges not drip by drip, bit in a gush of water, which helps the water stay warm as it travels down the pipe?

lagging, increasing pipe size, a syphonic heated trap, are all advantage against freezing, but the condensure is the biggest plus.

Min · 30 Nov 2018

Ah, ok. I thought 'syphonic trap' IS the CondenseSure!

JohnD · 1 Dec 2018

I don't believe there's a simpler, better or more reliable way than connecting the boiler's condensate into a nearby indoor waste pipe.

Obviously I chose that.

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Insulating a condensate pipe

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