Condensing boiler - how much condensate

[tonycollinet]

Bit of a panic this evening. Boiler stopped working. Diagnosed it to a frozen condensate outlet, which goes through the garage wall to a drain outside. I've cut the pipe inside, and it is now draining into a bucket.
 
Any idea how much condensate I can expect?

Thanks.

[rogerzilla]

I insisted that our condensate pipe was run internally, into the soil stack.

I reckon half a bucket an hour at full tilt, but that's a guess based on when our condensate trap, or more accurately its drain plug, sprung a leak a couple of years ago.  I fixed it with the cork from a bottle of port until British Gas sent me a new one.

[pcolbeck]

Same thing happened to my Dads boiler last week. Normally not an issue in the UK apparently but with the current weather ... He stuck some pipe insulation round the pipe that was external to the house (the internal bit was already insulated) and then boxed it in to keep the wind off. Has been fine since.

[tonycollinet]

Sadly, there is no accessible internal drain.
 
Im thinking of putting an inline tank in the pipe, with a tap to empty it. Normally it will just drain to the outlet - if this freezes, the tank acts as a bucket.

[tonycollinet]

Seems to be about 3 litres in 24 hours.

[rogerzilla]

A lot less than I would have thought - it shows how little of the steam they actually do condense - most of it still goes out of the flue.

Do you know if yours is running in full condensing mode?  The boilers are actually mis-sold; the efficiency of 90% or whatever is only achieved if you have the circulating temperature at 63 deg C which is considered "full condensing".  However, Potterton boilers, and presumably most others, are set to 84 deg C (or something like that) from the factory because they know that you can't actually get a cylinder full of hot water using 63 deg C in the primary circuit.  I tried setting it to full condensing mode (this is done by moving a jumper on the main PCB which selects the lower circulating temperature) and it was utterly hopeless - the water never got much above blood heat.

[MacB]

Thread resurrection and what a lifesaver - my ridiculously positioned boiler has a condensing pipe that exits upstairs, runs along the side of the building, round the back, then down - via bloody right angles and even an upward slope at one point - finally to the drain....about 10m all told. The boiler is to be moved to the kitchen where it belongs but this cold snap has caught me out. I know the problem is the pipe as the bottom end is frozen solid. But I can't get to all of it to thaw it and it needs proper lagging anyway.

Then a random search produces this and of course I can cut the pipe and drain to bucket until I can sort properly - YACF/Tony....thank you...it's bloody freezing here

[MacB]

Well since that post I have taken a hacksaw to the pipe, instant fix, done the dishes from the last couple of days and am now basking as the radiators pump out heat from a suddenly much quieter boiler.

If the local plumbers hadn't been so busy I'd have spent hundreds probably on this simple fix. I know cutting the pipe is only a temporary one but I really didn't see an alternative. About the only thing they'd got right was upping the size of the external pipe to offset cold/blockage issues. It's poorly and raggedly insulated, lots of gaps, and the run is simply stupid. The boiler is above the kitchen as it is so I think dropping the pipe straight down will form a part of the solution.

Anyway, thanks again from a much warmer MacB

[Aunt Maud]

Can't you drop it straight into the sink outlet pipe and connect it up with a bit of solvent weld plastic ?

[Polar Bear]

Looking at our Vaillant Ecotec boiler the condensing pipe goes straight through the wall and then pigtails on the outside.  There is evidence of outpouring down the wall.

This was fitted some years ago and I presume it was legal at the time though I note that the buy-to-let neighbours recent installation has a length of plastic pipe all the way down to the drain.

Our pipe exits immediately above the hot loop of the central heating beneath the boiler and is strategically sheltered from windchill by a soil / stack pipe.  I guess any new installation would involve simply dropping the pipe internally and connecting it to the washing machine waste conveniently situated below the boiler.   

[rafletcher]

The condensate is corrosive - it’ll eat concrete. Best piped fully away.

[hellymedic]

Having just had mine freeze up, I really wonder why these pipes are not either internally routed or routinely fitted with electrical heating tape outdoors. I am FURIOUS!

[Kim]

I guess any new installation would involve simply dropping the pipe internally and connecting it to the washing machine waste conveniently situated below the boiler.

That's how ours has been (shoddily) done.  The freeze occurred in the washing machine waste, downstream of the shoddy bits.  With hilarious consequences for the washing machine.

The problem seems to be that a slow trickle of water is a recipe for ice.  If it stored up a couple of litres of the stuff and chucked it all down the pipe in one go (like washing machines and sinks tend to) it wouldn't be such a problem.

In the absence of completely internal routing, the solution seems to be to keep the run as simple and (for ease of de-frosting) accessible as possible, which would seem to preclude mucking about behind the washing machine.

[andytheflyer]

The problem seems to be that a slow trickle of water is a recipe for ice.  If it stored up a couple of litres of the stuff and chucked it all down the pipe in one go (like washing machines and sinks tend to) it wouldn't be such a problem.

We've got a Worcester Condensing boiler and that's what that does, it must have a small tank because occasionally you hear a pump go on and it dumps the condensate down a 19mm pipe inside the garage wall, then out to a drain.

Or it did, now I know why the corner of the garage floor is often wet - I was blaming the garage tap in that same area.  There was about a litre of less-than-clean water in that corner this morning - and having cleaned up I now see that the pipe is actually cracked.  So that needs fixing asap. 

Hopefully, the servo plugs for the propped up wings on one of my RC aeroplanes, which were sitting in that corner, and submerged in the effluent, will be recovered by the soaking in WD40 that they are now getting.  Otherwise I'll have to fit new servo leads.......

[hellymedic]

I've not seen ours, due to mobility issues. I think it's straight and vertical, from the first floor boiler to the drain on the ground. That would be about fifteen feet, on a north-west facing wall.
Hardly surprising when it freezes!

[Mrs Pingu]

You can get pumps to install separately... https://www.mrcentralheating.co.uk/grundfos-conlift-1-ls-condensate-removal-pump#.WplchqmnxxA

[Kim]

You can get pumps to install separately... https://www.mrcentralheating.co.uk/grundfos-conlift-1-ls-condensate-removal-pump#.WplchqmnxxA

That's basically Saniflo tactics, thobut.  Nothing good can come of it.   

[Polar Bear]

I guess any new installation would involve simply dropping the pipe internally and connecting it to the washing machine waste conveniently situated below the boiler.

That's how ours has been (shoddily) done.  The freeze occurred in the washing machine waste, downstream of the shoddy bits.  With hilarious consequences for the washing machine.

The problem seems to be that a slow trickle of water is a recipe for ice.  If it stored up a couple of litres of the stuff and chucked it all down the pipe in one go (like washing machines and sinks tend to) it wouldn't be such a problem.

In the absence of completely internal routing, the solution seems to be to keep the run as simple and (for ease of de-frosting) accessible as possible, which would seem to preclude mucking about behind the washing machine.

Fortunately for us when we remodelled the Bear-o-Drome all of the waste at ground floor level* (where the boiler also is) is internally routed now so freezing would be very very unlikely indeed.   

* Kitchen and a loo

[Snakehips]

My installer kept the run as simple as possible by teeing in to my soil stack using a suitable adaptor. Otherwise he would have had to run the pipework past the kitchen door!

[andyoxon]

When we had a new boiler last last year, they put in a new consdensate pipe and soakaway; the previous installers had used too narrow a drain pipe apparently.  What has frozen up for us is the dishwasher drain, which has a sloping external run of ~3m...  The tube-into-drain overspilled last night, fortunately not in a major way.

[Sergeant Pluck]

I had this yesterday. There is a long run of pipe, much of it close to horizontal as it crosses a flat roof. It was solid ice all the way back up to where the condensate drain exits the wall on the first floor. No other option but to cut the pipe on a vertical - tubes of ice and a litre or so of water came out. Suspect there had been quite a build up of pressure.

I’ll get a coupler and repair the pipe at some stage.

As has been said, as there is only a few litres per day involved, these should be drained internally into the existing bathroom waste system or similar.

[JulesP]

And another one. I cleverly had my condensate pipe routed to the internal sink drain when the boiler was replaced a few years ago, after dealing with my mum's frozen external pipe one winter.

I've since discovered that that drain follows a long, tortuous and utterly baffling route from the sink under the floorboards at a 1-degree gradient, before exiting the outside wall at an upwards angle – thus leaving water in the pipe to freeze. Which it's now done, disabling the sink, boiler and dishwasher in the process.

The external pipe is a bugger to get at, too, and the internal one (with floorboards lifted) isn't responding to the hair dryer/swearing.

[andrewc]

I've just looked on 3 different forums, all devoted to different topics & on all of them people are complaining about problems with condensing boilers.  Even the woman on the checkout at M&S had had to defrost hers with a kettle of boiling water. 


Are these things not designed for cold conditions ?

[Sergeant Pluck]

Are these things not designed for cold conditions ?

Because the volume involved is not great, the condensate pipe finds itself subject to all sorts of half-arsed routing with not enough fall along horizontals.

[hellymedic]

Apparently not!
See also the RANT thread in the Pub and postings I may have made on Facebook.

This is a systemic issue that must be plaguing many thousands of homes. Winter comes every year. Cold weather comes often in winter, which is why we have heating.

HUGE numbers of folk have been sold systems that cannot cope with freezing conditions in winter.

I am seething!