Condensate insulated pipe 22mm external

Ambergreen45 · 3 Jan 2015

Hi,

Under sub freezing temperatures and a severe frost, I went to check the combi boiler's condensate pipe outside and noticed a small amount of ice coming out at the end. The boiler did not shut down, but I switched the CH off to prevent further problems.

The condensate pipe goes horizontal when passing through the cavity wall and is around 22mm thick. From the outside wall, it then immediately goes down into a fairly steep slope for about 1 metre before meeting the drain. It is fully insulated and is 22mm all the way.

I've looked at the manual and noticed the instructions saying it must be 30 or 32 mm minimum if going externally and before passing through the outside wall.

I'm not sure if this is a requirement or a guidance for installers but I'm wondering if 22mm fully insulated pipe is common practice on an outside wall or if I've been singled out?

Any advice/comments would be greatly appreciated.

Thank you.

leakydave · 3 Jan 2015

If it says that in the MI then that is what it should be. I always go for 40mm solvent pipe externally myself.

ScottishGasMan · 3 Jan 2015

If in the manufacturers instructions is says 32mm and from inside then this is what you should have.

Many installers either dont have the core bits to core a hole out for 32mm and too lazy to hammer out a hole to accommodate it. Plus 21mm is cheap and easy for them.

I dont however think youve been singled out, its a very common poor practice across the board but it doesnt make it ok.

Is the insulation the Grey Foam type? Chances are its not suitable if it is either, since most folk dont realize its not weather proof and slowly soaks up water helping it to freeze the pipe, and eventually it just perishes away over a few winters.

ALSO one last note, what kind of drain does it go into? a pic would be best if you can, and also what boiler it is? Some are fed into rainwater downpipes which for the most part are also not suitable.

ScottishGasMan · 3 Jan 2015

PS: if its that cold get a hairdryer on it if its not wet outside, or if it is pour a kettle over it outside to thaw it out and get yer heating back on!

Groovejet · 3 Jan 2015

Remember that bad winter about 4 years ago ...or so!!!
Well since then because everybodys condensate was freezing over and cutting boiler out, manufactures instructions now state that external runs should be 32mm diameter and securely clipped , obviously.!

Before this you could run 22mm condensate ....well 21.5mm to be precise, outside and into drain or soakaway...whateva!!

BUT....

If the run was over3meters then you had to increase it to 32mm diameter

Now, even a loft is classed as external space, so the same rule applies, it must be in 32mm

The only time it can be 22mm is internal runs
Manufacture instructions are not a guide to pick and choose, they are to be followed. If i doubt, always do as M.I say.
Hope that helps?

p.s- Only last month i had a condensate to replace that had a section of 22mm copper pipe internally, in the airing cupboad and 22mm to outside, basically it had corroded to the point of splitting pipe and causing a mess in house..... So just a warning only use overflow pipe or like i use solvent weld pipe.

Ambergreen45 · 4 Jan 2015

ScottishGasMan said:
Is the insulation the Grey Foam type? Chances are its not suitable if it is either, since most folk dont realize its not weather proof and slowly soaks up water helping it to freeze the pipe, and eventually it just perishes away over a few winters.

ALSO one last note, what kind of drain does it go into? a pic would be best if you can, and also what boiler it is? Some are fed into rainwater downpipes which for the most part are also not suitable.

I’ve got problems uploading pics for some reason. The insulation is the grey foam type and quite thick.. There were drops of water that froze from the dew on it overnight. The MI quote class O. Should it be a different colour?

It’s an Ideal combi boiler with a syphon and the drain outside is a gulley type with a cast grill on top to prevent leaves going in.

Happyplumber · 4 Jan 2015

Ideal ask for 42 mm external pipe and insulation as part of their instructions.Ideally it shoukd be run internally

Class O insulation is the correct type for external use and that is also stipulated in Ideal instructions.21.5 or overflow pipe is not correct material to use externally and so will not comply with Regulations

HOT water poured over the pipe using your kettle is a quick and easy way to get your boiler going in case where it has failed due to being frozen

ScottishGasMan · 4 Jan 2015

The grey insulation is normally the pound shop stuff BnQ sell and is not class O in most/all cases.

Which doesnt matter if the pipes not fitted correctly. The pipe from memory in the gulley type should terminate BELOW the level of the grate in order to avoid wind chill/reduce freezing. I'm guessing yours is above the grate?

ScottishGasMan · 4 Jan 2015

View media item 87683
Per Ideals own instructions

ScottishGasMan · 4 Jan 2015

Normal Pipe Insulation
http://www.screwfix.com/p/economy-p...F7KLZdBGTtU54-lU_AtRVdGgEqh7f001pmBoCcyjw_wcB

Class O
http://www.quickinsulation.co.uk/class-o-armaflex-pipe-insulation-15mm-diameter-13mm-wall.html

JohnD · 4 Jan 2015

Consider first if there is any way you can connect it to an internal drain.

Boilers are most often fitted in kitchens and utility rooms, which have sinks, washing machines and waste pipes.

Boiler installers might find it less work to drill a hole in a wall than to put a waste pipe behind kitchen cabinets. But it will be a lot more work and inconvenience for you if an external pipe freezes.

Ambergreen45 · 4 Jan 2015

Happyplumber said:
Ideal ask for 42 mm external pipe and insulation as part of their instructions.Ideally it shoukd be run internally

42mm is that the pipe diameter including insulation or just the plastic white pipe itself?

ScottishGasMan said:
Which doesnt matter if the pipes not fitted correctly.

???

p="3283390" said:
The pipe from memory in the gulley type should terminate BELOW the level of the grate in order to avoid wind chill/reduce freezing. I'm guessing yours is above the grate?

Mine ends just above the cast iron grate but sorry, I forgot to mention there is a rectangular metal cover just above it. So, the end pipe sits just above the grate but below the cover, you can see it without removing the cover and it seems protected from the wind chill. However that's exactly where I saw the small amount of ice sticking out of the end pipe. Apart from the incorrect sized pipe, is the end of the pipe in the correct place or should it still be below the grate?
I can now see the installation of a condensate pipe does not seem to be that straightforward…

ScottishGasMan said:
Class O
http://www.quickinsulation.co.uk/cl...sulation-15mm-diameter-13mm-wall.html[/QUOTE]
Out of interest, there is a 28mm, 35mm and 42mm insulating rubber pipe. If a 30mm plastic white pipe was replaced, am I right to think 30mm is the internal diameter, therefore the external diameter could be 35mm, in which case a 35mm diameter class O type rubber pipe insulation would fit?

Ambergreen45 · 4 Jan 2015

ScottishGasMan said:
View media item 87683
Per Ideals own instructions

Thanks for the diagram. Just an observation, it looks like the U bend for the sink is 19mm internal diameter minimum! At that size the sink would block so easily! I don't know if that's been overlooked by the manufacturers who drew that diagram but I've always seen U bends fairly large to prevent blockages.

Another question to satisfy my curiosity, the boiler has a siphon built in, is that the boiler's sealed 75mm condensate trap? Should the acidic condensate come out of the pipe dripping slowly or should it come out like a measured liquid being flushed out at regular intervals? I'm asking because I recently was looking at the end pipe outside when the CH was on and nothing was coming out of it.

Groovejet · 5 Jan 2015

Your starting to make this really complicated!!

Simply remove the 21.5 condensate pipe and install 40mm Solvent weld waste pipe ( glue fit ,last a very long time)

NO INSULATION ...no U BENDS OR CLASS 'O' SIMPLY ONE PIPE A COUPLE OF CLIPS A SOME GLUE!!

This way you dont have to use pipe insulation and your giving it the best chance to never bother you again.

Recap.....21.5mm from boiler to wall, then 21.5 x 40 connector to increase it going through wall to outside .........althougth you dont have to use 40mm to go through wall, you can use 21.5mm then increase it directly exiting externally.

bernardgreen · 5 Jan 2015

Because the flow of condensate is not much more than a trickle of liquid it will freeze when the air in the pipe is a couple of degrees below freezing.

Insulating the pipe slows down the rate of freezing but does not prevent it. Once ice has started to form it will continue to form and even a 35 mm pipe will eventually block with ice. The theory is that the cold spell won't last long enough for that to happen.

Insulation keeps heat in. It doesn't keep cold out.

Where freezing is likely to block the pipe it makes sense to install a means to thaw the pipe out. ELV (12 volt) trace heating is one option. I have run a hose pipe as trace heating. When the protected pipe froze hot water ( from a kettle ) could be run through the hose pipe to heat the protected pipe until it thawed. The important thing was to blow all the water out of the hose pipe once the system was thawed.

A tundish ( or air break ) inside the house with a plastic bucket under it would provide an emergency drain for the condensate should the pipe become blocked outside the house.

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Condensate insulated pipe 22mm external

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