Cold weather condensing boiler breakdowns x 2 Frozen condensate pipes

Ho hum - went shopping this morning and noticed my neighbour had a plumber/heating installers van outside. When I returned said van had gone and neighbour looked distinctly cold. On speaking to him it transpired installer knew nothing about the insides of the boiler despite having installed and "comissioned" it. Since he could not fix it he departed. We had very severe frost last night so I enquired if there was an ice plug in the condensate outlet. Neighbour got ladder out to look and it turned out there was. Soon neighbour had kettle out and a warm house soon after. An hour later my phone rang and a friend told me he had no heat or hot water. Jokingly I said it would be an ice plug in the condensate line. Ten minutes later he phoned back to say it had been just that and promised me a pint. It seems there is a distinct lack of appreciation of the effects of frost on condensate pipes by installers or are we afflicted worse than others in our area?

Reply to
cynic
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Do some pipes constantly 'dribble' out then? Mine is stored in a small tank in the boiler, then comes out periodically, maybe once a day. Alan.

Reply to
A.Lee

Same here, but I guess in this weather there's still a possibility of ice build-up over several days. Ours empties when the 'mini-cistern' is full, and I guess that is probably several times a day if the boiler is on all the time, enough to get a build-up if the pipe isn't insulated and it stays below freezing.

Reply to
Bob Eager

So it is not just me that is suffering then?

Adam

Reply to
ARWadsworth

I've a few different installers/repairers in action over the last few years. I think the number of them who have any idea how a modern boiler works is very low (none in my limited experience). First step is a call to the manufacturer. Only one actually tried to follow the fault flow chart, and failed to follow it (went from one box to another with no line between them), so second step was a call to the manufacturer.

Some years ago when I phoned Keston's engineer help line, and soon as I started talking about the flue gas CO2 level, you could hear the guy at the other end suddenly change gear - seemed to come as a surprise that he had someone on the phone who understood how the boiler worked. The bloke was very helpful and went into detail about how to fine tune it for very best operation, which isn't in the docs at all.

Reply to
Andrew Gabriel

My Keston does. It's slightly warm*, so it's not going to freeze unless there's a long run of exposed outside pipework. In my case, it has about a metre of 32mm plastic, before it enters the stack. Instructions did say not to use the 21.5mm pipework outside, but I do see this quite often when looking at other installations. It's never frozen, but I did have a similar effect when the drain hole from the heat exchanger got blocked with some crud, and it started filling with water until it blocked the flue outlet enough to stop it lighting. It has a detector on the drain pipe backing up, but that's after the heat exchanger drain hole, so it doesn't detect that until it prevents combustion.

Many years ago, I plumbed in a small portable dehumdifier, which trickles out condensate. I made up a length of thin heater wire, by threading a length of resistance wire down about 6m of thin PTFE sleeving (which turned out to be really difficult), and threaded this, doubled back on itself, inside the 3m of external plastic hose. Selected a transformer voltage so it was heated at about 18W, and connected it to an outside frost-stat. That never froze. (This has been decommissioned now, because I collect the condensate water for some plants which can't handle tap water, and for ironing.)

  • I have my boiler set very low - about 45C flow. With more normal boiler temperatures, the condensate is going to be hotter - I suspect about same as the return water temperature. However, with the boiler set very low, I am going to be generating more condensate than most.
Reply to
Andrew Gabriel

Reply to
Andrew Gabriel

My Baxi Solo has 21.5mm plastic and appears to be designed for it. You certainly couldn't couple 32mm to it. The 21.5mm runs for a good 3 metres and hasn't frozen it the recent heavy snow.

My CORGI mate installed the boiler & took the 21.5mm out through the wall & I finished the run. I asked him about insulating it & he said it wasn't necessary.

I guess the Baxi Solo dribbles as well - never really looked.

Reply to
The Medway Handyman

I think they're all designed for 21.5mm plastic. You can buy a 21.5 to 32mm adaptor, which is what I used.

Often the internal radiator pipe type insulation is used. Someone used this on an external water pipe on an office next door to one where I was working. Halfway through the day, a large fountain suddenly appeared. I went to have a look, and the insulation was all waterlogged, so it was doing nothing. You'd need to find some insulation suitable for outdoor use. The closed-cell foam as used on aircon chilled water pipework should be fine in that it can't waterlog, although it might not be UV stablised.

Reply to
Andrew Gabriel

21.5mm - 32mm adapter readily available for a few pence.

Most boiler manufactuers instructions reccomend 32mm plastic pipe for external condensate waste.

Reply to
Heliotrope Smith

Our Vaillant empties out the condensate quite a few times a day, the internal run is 21.5mm and as it soon as it leaves the building it is in 32mm pipe, apparently if you use 21.5mm pipe outside it should be lagged but 32mm pipe is fine. It's never frozen.

Reply to
David

Thanks for posting this. Seriously pleased you did!

Heating came on this morning and then turned off unexpectedly. Checked the boiler, saw it was locked out, reset it, it started but sounded as though it was full of air from the gurgling sound. Looked outside to check the plume, no plume and the gurgling was even louder, as though the fan was blowing through water rather than the pump trying to pump air.

Remembered this thread, got the kettle out, and poured it all over the external elbow from the condensate drain pipe. The boiler has now restarted.

Management had placed a tile over the drain cover into which the condensate pipe empties after a low level near horizontal run. Looks like the last time it flowed it froze at the end of the pipe as it couldn't fall and clear the end. The ice plug just worked its way back along the pipe until the whole lot blocked.

There is an air gap between the elbow that exits the wall and the wider vertical section of pipe but it just froze backwards and filled the gap before working even further backwards and blocking the pipe completely.

Can now get back to wallpapering the bedroom with the paste table in the garage with a wide open door and the temperature sub-zero...

Reply to
F

Some people get all the good jobs.... :-)

Reply to
The Medway Handyman

Thought you'd be busy setting up a branch of TMH dedicated to hauling broken-down Eurostars or supplying stranded passengers with refreshments, sleeping bags, taxis etc...

Reply to
F

Trans Manche Haulage?

Reply to
Rod

Nope seems about standard. I think I probably posted this before:

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was how a CORGI left my neighbours new boiler after installing it. He drilled a hole through the wall, stuck a 15mm copper pipe through the hole and then turned the pipe down with an elbow and took it to path level (at an angle of about 15 degrees this time). He the wound insulating tape around the end of the pipe and pushed the corrugated condensate pipe over it. In reality it probably would not have frozen since most of the condensate seemed to drip out of the joint and onto the kitchen worktop before it actually got as far as the metal pipe or path outside!

Reply to
John Rumm

No, from what I hear it's little old ladies too.

Maybe you can tell us more ;-)

Reply to
YAPH

What a pigging mess. Isn't the solder supposed to be on the inside of the joints? And judging by the amout of green corrsion about he used an acidic flux and didn't wipe it off afterwards.

Reply to
Dave Liquorice

Yup, he seemed to be an adherent to the rendering school of soldering.

In spite of all that solder, the original installer (the pissed up mate of the CORGI) managed to leave several gas leaks! At least when the CORGI returned to look at it later he made it gas tight - but no less ugly.

The boiler was hung 5 degrees off the vertical, and they declined to connect it to the existing prog stat on the grounds that it was "incompatible".

I suggested that the neighbours ought to report them to CORGI and also refuse to pay until the work was done to an adequate standard. Alas they were not up for any additional hassle, and did not want to let them back in the house again.

So neighbour and I managed to get the boiler nearly vertical. I redid the condensate drain in plastic and took it internally into the sink waste, hooked up the stat to the waiting terminals, and boxed in the pipes which made it look a bit better.

Reply to
John Rumm

There's probably just as much _inside_ the pipes...

Reply to
Andrew Gabriel

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