Why oh why are they so badly designed? Boiler broke down yesterday, Gas man comes out, pours hot water on the outside pipe, hey presto it works again. 11pm last night, more ominous noises, packs up again. Now they can’t come out until tomorrow. I would attempt unfreezing the pipe myself, however, the iced part is up at the first floor, out of my reach!

I can see where the problem lies, the pipe comes out of the wall horizontally and then takes a right angle to go down to the ground. Obviously the water is freezing before the bend.

Anyone got any tips how to avoid this problem? Left the heating on last night, no difference, it still froze. Gas man says lagging the pipe won’t make any difference.

Help! Given we live in the West of Scotland, it could be a long winter of breakdowns!!

Lagging will help. Shelter it from any wind/the elements.

pipes are supposed to be lagged for any outside runs I think.

some of that foamy pipe insulation is probably worth a try.

re: what to do now tie a hairdryer on an extension lead to a long stick/broom handle 🙂

Join the club! It is still -2 here so cant see it thawing out any time soon and the water backed up into the boiler so dont know if it cause any damage there in any case. Just flashing lights for me. Plumber is coming out this afternoon

I assume you’re talking about the condensate pipe? If so I know people who have cut the pipe as close to the boiler once the pipe it outside the building so the condensate has less time in the pipe to freeze. Only a temp fix mind, and the pipe will need replacing once the cold weather is over. Ours sometimes freezes right as it goes into the drain, which is a doddle to thaw out just by running a kettle of hot water over the outside of the pipe and then tapping the slug of ice into the drain.

Briiliant, off to B&Q to get some lagging and will then have to MTFU as I hate ladders!

wwaswas- Loving the hairdryer idea!

It is the condensate pipe that’s causing the problem. I’ve also heard of it being cut short, however, as a short term fix, surely replacing the cut section in the summer just causes the same problem next year?

On the British Gas website, they’re showing some sort of heater element that can be fitted and kicks in automatically to stop the pipe freezing. Anyone know of this being a success?

It is the condensate pipe that’s causing the problem. I’ve also heard of it being cut short, however, as a short term fix, surely replacing the cut section in the summer just causes the same problem next year?

Correct, though knowing where the icing problem is means you can then modify the condensate pipe routing to help make it less of an issue (maybe), or move the icing point to somewhere lower down so you can de-ice yourself/not at high level (maybe).

No idea about the heater, though obviously the longer/more convoluted/lack of gradient will mean the potential for icing is greater.

Yes, having a horizontal piece of pipe seems like a recipe for disaster, not very well thought out at all. Will see what the “expert” thinks tomorrow.

Hot water bottle on a stick/ rope and leave it at the iced up bit till it thaws ?

Yeah this has just happened at my mums house, years and years of a virtually trouble free boiler. She then buys this new one as it’s all eco, only for it to be useless in the winter when you actually want heat. Massive design flaw!

We had exactly this problem last winter, the plumber poured hotwater on the condensate pipe outside to defrost. I agree with the others that insulating it would help, would be a better design to run the condensate pipe into an internal drain that can’t freeze! Maybe this can’t be done because of Carbon Monoxide?

stand on roof and pee on it if you can’t reach from grund level.

Indeed it should be insulated once outside.
Instead of this I have the pipe going up into the loft and across to my soil pipe so that it is all internal and there is no risk of it freezing. It does, however, require a small pump to raise it from the first floor into the loft. The pump just comes on every now and then, so is not of much concern.

The condensate is mildly acidic/corrosive, so don’t leave it running down a wall for long if you don’t want bad staining.

Tails – It freezes because it’s ‘Eco’. The condensate temp is low because it’s not vented in/as an exhaust gas as in older boilers, therefore capturing more heat from the source fuel. You can call higher thermal efficency a design flaw if you like……

Internal routing is permitted IIRC and, as MLC says, the condensate is corrosive, which is the reason from the continuous routing from the boiler to drain.

Guys, thanks for all the replies, you’ve been very helpful.

The bloke who put our system in actually teaches plumbing after many years in the field. He did an excellent install for us, so professional and neat. Our condensate pipe is internal, and drips into a plastic cup type thing which goes straight to sewer. Nothing outside at all.
Mind you, he also plumbed it in so all you have to do to drain the entire system is connect one flexible pipe and turn a lever and the entire system drains to the sewer. No buckets or hoses or anything.

The boilers are designed well, it’s just the muppets that fit some of them that are the real problem. 🙂

Our condensate pipe is external but angled at about 45 degrees to the soil pipe and lagged. Been ok this winter (was new in April).

Mines doing it too, keep getting error, pour hot water on outside pipe and all’s well. My plumber visited yesterday and said I was the 4th customer that day with same problem. Fortunately mine’s accessible and vertical.

Our boiler saves up the condensate then periodically dumps it so there’s less chance of it icing up and blocking over time. I don’t know whether all boilers do this. In your circumstances (in need of a quick fix now) I’d just disconnect the condensate pipework near the boiler and put a bucket under it, emptying periodically of course. I wouldn’t be up a ladder trying to fix stuff in this weather, it can wait until summer.

Yup same thing happened here, as daveh says if you’re in an emergency then just cut the pipe off internally and catch it in a bucket.

For a permanent fix get the pipe redone without the horizontal section and get it lagged too.

Worcester boilers recommend going up a pipe size to 30mm from the more normal 20mm, although that’ll need the hole in the wall opening out too…

Thanks again guys.

Same problem here but the whole pipe was frozen, about 2m of it in the garage to outside wall. Took the whole thing off (save the down pipe from the boiler) and now draining into a bucket (the first bucket shattered when I moved it because it was so cold)

Good advice on the Wolseley website, saved me an expensive call out.

Our boiler condensate pipe is routed to the drain internally as well thus eliminating the problem.

same thing on monday morning. Called a plumber friend who installed boiler who told me what to do. Mine runs out into a larger downpipe into a gutter for a conservatory. The gutter froze up preventing the downpipe from running out which froze right back to the boiler. Hot water and dropping the down pipe off and it’s been fine since.

Plumber said he’s had loads of them since cold spell started. Didn’t have problem in jan/feb coldspell though.

Why oh why are they so badly designed? Boiler broke down yesterday, Gas man comes out, pours hot water on the outside pipe, hey presto it works again. 11pm last night, more ominous noises, packs up again. Now they can’t come out until tomorrow. I would attempt unfreezing the pipe myself, however, the iced part is up at the first floor, out of my reach!

They’re not badly designed, they’re poorly installed. The condensate drain should be at quite an angle to allow it to drain away quick, and should be lagged properly so it doesn’t freeze. Whoever installed it forgot some part of the above, as mine did, I’ve now got it detached and emptying into a bucket.

It always used to be that the condensate had to go into an internal trapped drain; has that changed? If the condensate can’t get out it can cause fan failure on boilers where the motor windings are in the combustion chamber.

Our condensate has a drain plug, when it drops below freezing for any length of time I simply remove the plug and put an old sauce pan under it. Simples.

It always used to be that the condensate had to go into an internal trapped drain; has that changed?

Don’t know if it’s ever been “forced” but it would make sense. However the manual for my boiler doesn’t suggest it as necessary. Lagging it is though!

If the problem persists and is an inconvenience to rectify you could invest in a trace heating element. A small filament of wire is inserted in the pipe and when the temperature drops below s predetermined level the wire heats up preventing a frozen pipe.
As a side issue you also get trace heating for gutters as a few insurers are getting pissed of paying out for roof repairs every year when your gutters ice up!

pipe lagging outside may make the problem worse as it is not waterproof. I suspect that in the instructions it tells you how to run your condense externally. Usually it is one pipe size larger, ie 32mm waste pipe. However the condensate should still discharge to a suitable location, ie drain, soil pipe, or specific condensate soakaway located correctly. always best to discharge into the internal plumbing system if possible, but boiler locations are not always as accomomdating as that!

+1 Bear
only lag the pipe if you can make it totally waterproof, or it’ll freeze up and you’ll not be able to thaw it.

Most pipe lagging I’ve seen is closed-cell foam and waterproof?

You’d think that an appliance which is designed to heat water could have a winter mode which would provide a small amount of heat energy directed to the condensate outlet to stop freezing.

I wrote a letter to British Gas. HTH.

When British Gas installed our boiler at far greater expense than a local engineer would have charged, I assumed I would be receiving a much higher quality of service. Unfortunately I was mistaken. Last winter (the first winter the boiler was used), the boiler broke down right at the coldest time of the year. I contacted British Gas and since I was and have been a Homecare customer for many years, I assumed I would get a rapid response. After all, I could have got a local engineer round for a fraction of the cost who would have fixed the problem quickly. Again, this was a rash assumption.

After 3 days of no hot water or heating, a British gas engineer turned up, pronounced the installation as one ‘done by cowboys’, got his hacksaw out and sawed right through the condensation pipe, which fixed the problem. Took him all of five minutes.
Later on (after the weather had warmed up) another engineer turned and reconnected the pipe.

What do you think happened this winter? Yep. Exactly the same thing. Faced with the possibility of another 3 days without hot water or heating (if I was lucky), I took matters into my own hands and resolved the issue myself, I do after all, have a hacksaw of my own.

The matter still remains though. The installation is clearly substandard if it breaks everytime we have a cold spell. It is time for British Gas to resolve the issue permanently. Please explain how and when you intend to do this. I will not accept someone turning up to reconnect the pipe. This is a design flaw which needs a bit more intelligence applying to it.

I’m not expecting British Gas to get back in touch myself.

Trace heating

jamesy01 – Member
If the problem persists and is an inconvenience to rectify you could invest in a trace heating element. A small filament of wire is inserted in the pipe and when the temperature drops below s predetermined level the wire heats up preventing a frozen pipe.

no standard pipe lagging is not waterproof, you can waterproof it by painting it with hammerite or similar.

You can buy waterproof pipe insulation, however when I enquired I couldn’t just buy a few lengths at a time, had to buy a box of several hundred metres which which I would never use up. Also I was quoted I think nearly a £1000 for a box! No wonder most people don’t bother, but there is a solution to doing it the correct way as I said.

B&Q, cheapest possible pipe lagging is closed cell polyurethane foam. Closed cell, it’s fully waterpoof (except for the split of course!). The only reason I can see for non-waterproof lagging being a problem is if it soaks up water and then the evapouration with wind makes it susceptible to windchill effects, thus cooling the pipe more. But with a foam that has closed cells there’s nowhere for the water to sit (other than the surface, which is the same with all lagging) and so it can’t alter the heat conduction in any way, and doesn’t require painting.

Can someone explain to me why a closed cell polyurethane foam is not waterproof?