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tinytim1458

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Was not sure where to put this but maybe after reading this the moderators might.

We have a combi boiler that condinsates the water out to guttering outside. (yes you know whats coming) the condensation pipe has loads of waterproof foam insulation round it to stop it freezing but every year it still freezes up solid whenever we get a cold spell.
Would building an insulating box round it help. ie just a box covering the pipe and pipe insulation but packed with more insulating material (a lot maybe).
What would be the best material to use for the box, maybe some kind of wood but what wood and what waterproof insulation should i use as i should not need to much should i.
Does anyone have any ideas or has anyone already solved this problem and could help.
Thanks Tim
 

marcros

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it will help, i would use plywood. also try to shorten the pipe is much as possible
 

paul-c

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hi tim
this is a common problem as you know.
you can now get trace heaters (condensate pipe heaters ) to fit to the condense pipe
which gently heat the pipe to stop freezing when the temperature drops.
my dad had one fitted a couple of years ago and now doesn't have any problems with his boiler in the freezing weather.

the sort of thing on this link
http://www.heatingsupport.co.uk/blog/586/trace-heater-kits/

hope this helps
cheers
paul-c
 

Digit

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My wife looked at me in astonishment 'tother day, 'Insulation will not prevent water freezing if the temperature falls below freezing for long enough,' I told her as she was busy wrapping insulation around the outside taps.
The following day the taps froze!
The only way to guarantee that a pipe full of water won't freeze is to apply heat, for which purpose the best means is probably to use a heating cable.

Roy.
 

Eric The Viking

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It's a slightly surprising problem, Tim.

We have one at the top of the house. It drips into the guttering, it's on a fairly exposed corner, and as far as I know it's never frozen.

Is yours in a very exposed place, or does it get a lot of wind blowing at it? If so, then boxing it may well help quite a bit. Roger's idea is also good: surround it with a bigger pipe (40mm is 1 1/2" plastic waste pipe size).

It doesn't need to be a long pipe outside, just one that lets the condensate drain away rather than drip into free air. This is because it's slightly acidic and the drips might well hurt the house brick (or whatever). Draughts in your boxing-in will also cause it to freeze (although not as fast as without), so it's probably worth stuffing the woodwork with fibreglass insulation round the pipe.

Hope you get it sorted...

E.
 

devonwoody

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I hope you get the problem sorted.

Personally I think building regulations need putting into place and these type of boilers should not be fitted without adequate drainage being available and the old type of boiler should be the norm in that case.
 

Eric The Viking

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devonwoody":mb5tcxd4 said:
I hope you get the problem sorted.

Personally I think building regulations need putting into place and these type of boilers should not be fitted without adequate drainage being available and the old type of boiler should be the norm in that case.
Well that's what the instructions insist on!
I suspect, if it's fitted against manufacturer's instructions, it's probably breaking the rules anyway.

We're overlooked at the back by a rather nasty five-floor block of flats (wholly out of character for the area). About three years ago, several of them had condensing combis fitted by a fly-by-night outfit. One of them has either got a pressure valve leak or the condensate drain was simply shoved out through the wall. It's now created a stain down three floors:
stain.jpg

Sorry - rough pic - not much light at 0745! The stain goes on further down too.

Over time that will cause rot to any galvanised wall ties (likely, as my guess is that it's circa 1965 construction), cause frost spalling on the surface of the bricks (break them up), break up any dodgy pointing similarly, and possibly cause damp on the inside of the flats (but it's cavity). never mind how it looks. Frankly, only demolition would be an improvement aesthetically though! My guess is that it's actually a pressure valve leaking, not the condensate drain, and the vent pipe is too short. It should turn down and slightly toward the wall, but that's evidently running straight down the outer skin.

In case you're wondering, I told the residents about it two years ago, soon after it started!
 

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devonwoody

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ETV, I thought after that gas explosion in flats many years ago, gas was not allowed in multistorey buildings?
 

Lons

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Eric The Viking":rmch4f4f said:
It's a slightly surprising problem, Tim.

We have one at the top of the house. It drips into the guttering, it's on a fairly exposed corner, and as far as I know it's never frozen.

Is yours in a very exposed place, or does it get a lot of wind blowing at it? If so, then boxing it may well help quite a bit. Roger's idea is also good: surround it with a bigger pipe (40mm is 1 1/2" plastic waste pipe size).

It doesn't need to be a long pipe outside, just one that lets the condensate drain away rather than drip into free air. This is because it's slightly acidic and the drips might well hurt the house brick (or whatever). Draughts in your boxing-in will also cause it to freeze (although not as fast as without), so it's probably worth stuffing the woodwork with fibreglass insulation round the pipe.

Hope you get it sorted...

E.
I'm surprised you get away with that Eric, I'm not sure it's allowed now. - as you say, the condensate is acidic and therefore should drain into the foul system to the best of my knowlege and not surface water (which yours is), though I stand to be corrected. Neither of course should it be allowed to just drip out down the walls :shock:

Frozen condensate pipes can lead to early boiler failure, a fact that has come to light over the last couple of hard winters and it's a problem concerning building authorities and manufacturers alike.

I changed my oil boiler 1 month before the regs changed, specifically so I could put in an old type non condensing type. I did the calcs and difference on paper in efficiency was less than 1.5%. I think the new ones have a shorter life so another example of change purely to meet EU targets and of no benefit IMO

Tim

Go with the larger pipe / box in solutions. Can the pipe be partly re-routed indoors to shorten the external exposure? If boxing in, providing it's waterproof then you can use glassfibre insulation though if you want to do it on the cheap, even loads of bubblewrap will help a lot.

Bob
 

Eric The Viking

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Lons":1jeihs6b said:
I'm surprised you get away with that Eric, I'm not sure it's allowed now. - as you say, the condensate is acidic and therefore should drain into the foul system to the best of my knowledge and not surface water (which yours is), though I stand to be corrected. Neither of course should it be allowed to just drip out down the walls :shock:
Our house is of sufficient age for the rainwater to legitimately drain into the sewer. The condensate discharges almost directly into a downpipe. There is the usual gully below, 'tis true, but that downpipe takes sufficient rainwater flow to flush it regularly. All is plastic, with a 6" main drain (no salt glaze).

I changed my oil boiler 1 month before the regs changed, specifically so I could put in an old type non condensing type. I did the calcs and difference on paper in efficiency was less than 1.5%. I think the new ones have a shorter life so another example of change purely to meet EU targets and of no benefit IMO
I quite agree. Ours (gas, never-again-Vaillant) system boiler is about 6 years old and has a current annual run-rate of over £300 in actual repairs. It's eaten a pump, three sets of service valves (p**spoor design, £80/set+fitting), and a fan+controller. It's also leaked combustion products into the room (faulty seal - wrong material!), and suffers from crud in the pressure relief valve (poor design). Every summer recently I've weighed up replacing it, but there's always been some more pressing domestic issue. Vaillant's support is dreadful, and it appears they are using the motor manufacturers' model: spares are profitable!

Within reason, I'm convinced that simpler solutions are probably more energy efficient!

E.
 

Lons

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Eric

Forgot about combined sewer systems :oops: :oops: - and me a builder :!:

I agree with you about simple systems. Modern boilers definately have a short life compared with older units. But that's true of many things in our throw away society is it not. It isn't the first time I've heard complaints about Valiant

Bob
 

Cegidfa

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Hello Tim.

Boxing in with insulation is a waste of time. I made a big box cover stuffed with fibreglass adjacent to the pipe and then fitted celotex (50mm) to the inside of the box walls.
The pipe froze shortly after and the acidic water backed up into the boiler, eating away at the ceramic fire liners, the igniter and the flame failure probe.
The only way (apart from trace heating) is to divert the condense pipe into the inside 11/2 pipe from the sink or washer. This worked for us in the -16 temps last year.
It was the way the manual said to do it; pity the plumber didn't read it. Our boiler is a Viessmann, and that is what the Germans recommend.

See below our approach



This is what happens when the water hits the boiler innards.


Regards...Dick.
 

Digit

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When I installed ours I couldn't run it inside as such, but there was a drain outside in a suitable location, so I ran the boiler's pipe work into a 1 1/4 inch trap then through the wall into the drain.
Lagging an open ended pipe will have no effect on the temp of the pipe as the inside of the pipe is at air temp.

Roy.
 

devonwoody

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What would happen digit if you plumbed the outlet pipe into the drain with the outlet below the drain water level?

I imagine that drain water above trap does not freeze, the sewers keep it warmish?
 

Digit

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Never tried it DW, but it sounds reasonable. Using a larger plastic pipe was easy for me because of wooden walls, but a decent HVE should have core drills to cut through brick and do away with small dia copper.

Roy.
 
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