Waterproof pipe lagging

Horizon81

Bought a house earlier this year and the last owner mentioned that the condensate pipe on the boiler occasionally freezes up in winter.

Being the proactive type that I am, I want to try and prevent this this coming winter. The boiler is downstairs, with the 21.5mm condensate pipe exiting the wall, then straight down at a 90 degree bend vertically into a drain. Just past the 90 degree bend, the existing 21.5mm pipe goes into a 32mm pipe, where british gas tried (halfheartedly) to solve the problem. Whilst it helped, he advised that it sometimes still freezes up. I'm guessing the 21.5mm 90 degre bend is the weak point.

I know the correct way is to re-route the pipe internally but I'd rather look at lagging the pipe outside. Does anyone know where to buy waterproof pipe lagging - not having much luck on plumb center website or anywhere else.

cajef

I used a water resistant foam pipe similar to this a couple of years ago, they also do a white one that is suitable for underground so would imagine that must be waterproof.

http://www.insulationandlagging.co.uk/Pipe-Insulation/Class-0-Armaflex-Self-Seal-Pipe-Insulation-Lagging-Self-Adhesive


http://www.insulationandlagging.co.uk/Pipe-Insulation/Underground-Pipe-Insulation

zzzLazyDaisy

The 90 degree bend is the problem.

My condensate pipe ran down the wall then a 90 degree bend to the drainage pipe. The last bit ran along the ground and didn't have much/any slope. In very cold weather, the water collected and froze around the joint and then backed up until it flooded the boiler.

Lagging on its own didn't help, so I had the pipe re-routed so the joint was higher up the pipe and the second part ran diagonally down across the wall to the drainage pipe.

This seems to have cured the problem although last winter was not as cold, so who knows.

keystone

It should have been done in 32mm waste pipe in the first place rather than overflow pipe. Anyway your best solution would be to box it in and line the inside of the box with some insulation.

Cheers

ROY47

I cut mine off at the 90 bend where I had the same freezing problem 2 years ago

Mine now drains into a kiddies "sand castle bucket" and I empty the bucket into the drain when it's nearly full

problem solved , it's never frozen up since

Horizon81

Thanks for the replies. The run is almost completely vertical, obviously it exits the wall then hits a 90 degree bend and points downwards on a slight diagonal to the drain.

I'll try and get some 25mm wall x 22mm bore armaflex for it.
Cajef - how come the price on the website you mention is £5.96 for a 2 metre piece whereas its over £40 in plumbcenter for teh same length!?

T_T_2

Horizon81 wrote: »

how come the price on the website you mention is £5.96 for a 2 metre piece whereas its over £40 in plumbcenter for teh same length!?

Because the list price for Tubalit and Armaflex is notoriously high. Decent discount for trade customers can be anywhere from 65-85% off list. All plumbers' merchants will have what they call a 'trade cash backdrop account' This is cash account that they book goods to when a non-account holding customer comes in. It automatically applies the kind of terms you would expect to get as a one off trade customer rather than a retail customer. Next time ask them what the trade cash price is.

Horizon81

So it doesn't matter if you're a non trade customer?

Or what about a standard foam lagging, but coated with duct tape? That should waterproof it shouldn't it? We're not talking about a very long run so wouldn't take long.

T_T_2

Horizon81 wrote: »

So it doesn't matter if you're a non trade customer?

Or what about a standard foam lagging, but coated with duct tape? That should waterproof it shouldn't it? We're not talking about a very long run so wouldn't take long.

Waterproofing isn't the main problem, exposure to UV is the real problem. Foam lagging (I assume you mean tubolit/climaflex type of pipe insulation - the grey stuff) will start to deteriorate over time as it is exposed to the sun. I'm not sure how much this will be mitigated by duct tape. The Armaflex (black stuff, also known as donkey d*ck) is UV stablised and will not deteriorate in the sun.

Edited to add: I should have specified that only Armaflex HT is UV stabilised. I've just been told that they also do a product called Armaflex HT S that is specifically made for use outside.

ListysDad

A bit of advice if I may as this is my specialism...

Firstly, only nitrile based insulation is suitable for retrofitting for frost protection. The reason for this is because the polyethylene stuff (climaflex and its ilk) starts to physically shrink at 4 degrees centigrade not MINUS 4 but 4. In addition, one cannot glue polyethylene insulation effectively so you cannot make a vapour barrier.

Secondly, freezing occurs when the heat in the water is lost. Obviously this occurs literally in a second with the small drips of condensate into the pipe. Oddly enough, despite the advice to increase discharge pipe size, that makes matters worse. Air currents, that circulate in a larger diameter pipe, cause faster cooling so I NEVER increase the condensate pipe size. If I have to run it outside, I set it off the wall and install 32mm wall armaflex. I also never run 90 deg bends but instead have 2 x 45's. Lastly, if it must be outside then run trace heating (again on the smaller pipe) and instead of 32mm insulation us just 13mm wall as any thicker can cause the trace heating to overheat and burn out.

Regardless of the insulation, make sure it's installed properly. That means gluing all joints and fitting it under approx 10% compression to accommodate its shrinkage when it begins to get really cold.

If I can help any further just ask.