Boiler stopped - condensate pipe frozen?

8 Jan 2010
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United Kingdom

First post here so hello all and thank you for the wealth of information that I have stolen since I found this forum.

I have an Ideal Icos HE12 boiler that stopped working. FL flashing on display, on reset makes a lot of noise then stops and flashes FL again. After a little flick through the forum I considered my condensate pipe to be blocked and given the weather that that it was probably frozen. I have poured boiling water over the pipe and lagging and reset the boiler. It made even more noise but now appears to be working and as quiet as it was before.

What I would like to know is - Have I made a mistake in pouring boiling water over frozen condensate pipes and their lagging? What is the chance of this happening again and would more lagging help prevent this? It is an external pipe that comes out of the boiler through the wall then vertically down and runs under the back door step to the drain.

Also on a separate note am I right in thinking that condensing boilers don't need a hot water tank? And if so why have I got one? It's a new house to me, previous owner had the boiler installed.

Thanks people!
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Not the best idea to get the lagging too wet. If you can swap it for some dry stuff or dry it out with a hair dryer or it will freeze pretty quick.

Condensing boilers can have hot water tanks- COMBI boiler don't have hot water tanks (99% of the time)

Mixing up condensing boiler with combi boiler happens all the time.

Thanks very much, hadn't considered the wet lagging re-freezing :oops:

combi/condensing I do get confused, thanks again.

combi/condensing I do get confused, thanks again.

You'd be amazed at the amount of people that get confused on that.

One of my older customers asked me if his old boiler goes does he have to have "one of those new comical boilers?"

He wasn't far off being right.

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I would just like to say how grateful I am to this forum, my heating went off yesterday and would not re-set, I did a search for a gas engineer on google and this forum was amongst the results. Anyway thanks to this thread and a kettle of hot water I am now warm again and have not had to find £168 that I was going to pay for a fixed price repair. Thanks again and Happy New Year.
Had the same issue with an Ideal Isar combi yesterday. Managed to get a next day visit from Gas Board so didn't try the hot water on the condensate pipe. When they turned up they hacksawed the pipe just below where it comes out the wall outside. Told me if this bit freezes up then pour hot water on it. When the weather improves they'll come back and rejoin the pipe.
Hi there - a quick solution as many have previously said is to pour hot water on the pipe

However - you could end pouring a few kettles - a much preferable option is that if your condensate pipe lead outside to a cover/stones then it might be easier to first follow the pipe to the ground - at the end you should see a cover - carefully prise open the cover on the ground (it may be covered by stones and quite stiff to remove initially - so a flat head screwdriver maybe helpful) once open - pour hot water into it, followed by pouring another kettle of hot water on the pipe (especially on the joints area). The steam rising from the ground and the hot water should help ease the ice from sticking to the inner walls of the pipe.

Once complete, if you revisit the ground where you prised open the cover, if you put your hand underneath the end of the pipe - you may feel a large chunk of ice - carefully break it off piece by piece (it may take a few minutes to get rid of all the ice that is frozen within - but it should be much quicker that boiling and pouring numerous amounts of hot water. - (Gloves recommended)

Alternative, regular check up is a good idea i.e. once a week with a kettle during cold spells should help out - or if serious - once every evening. Might be a bit of a hassle - but it much better than freezing and spending 2 hours pouring hot water down a pipe during 3am in the morning in -6 temperatures!
even easier is to disconnect the condensate pipe from underneath the boiler, place a bucket underneath to catch the liquid, get your boiler going.

then de-ice the pipe later or wait until it thaws, better than being cold while you try and fix it.

i had this problem which BG did not identify, fixed it myself by replacing the 22mm condensate pipe going outside that BG installed with 32mm pipe. Saying that, it was so cold this winter that even that froze, at least it last longer as the pipe can hold more volume.

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