Vaillant condensing boiler freezing - minimising condensate?

BooJewels

Eldi_Dos said:

BooJewels said:

Eldi_Dos said:

@BooJewels

Could the proximity of the water butt have any bearing?
If water butt has frozen it will act as a cold store helping to keep the condensate pipe cold enough for to cause the freezing.

I have no idea, they've always been in the same position.  You could also perhaps argue that the water butt keeps the worst of the wind off the pipe and provides some shelter.  I truly have no idea.  Neither can be moved, so I'll have to work with what I have.

The water butt set up looks like a good thing from a gardening point of view and I would not suggest any physical changes.

If the butt has been full of water and it has frozen it will be pulling down the temperature in that area. What I would look into doing is draining down the butt between November and late March.

The empty butt with a lid on will heat up to a certain extent when it has the sun on it and may provide a warming roost for our feathered friend's. Always nice to see them about.

Good idea to drain the butt, it could certainly do with an interior clean.  But I don't know how I'd stop it from re-filling, I don't understand how the connector in the drain pipe works - presumably I'd have to disconnect one end of the flexible connecting pipe?  I have a very tall and steep pitch roof and that butt would fill very quickly in a decent shower as there's a lot of water passes down that pipe.

Sorry to sound so dense - every new job like this I tackle ends up being a steep learning curve.

bjorn_toby_wilde

BooJewels said:

Eldi_Dos said:

BooJewels said:

Eldi_Dos said:

@BooJewels

Could the proximity of the water butt have any bearing?
If water butt has frozen it will act as a cold store helping to keep the condensate pipe cold enough for to cause the freezing.

I have no idea, they've always been in the same position.  You could also perhaps argue that the water butt keeps the worst of the wind off the pipe and provides some shelter.  I truly have no idea.  Neither can be moved, so I'll have to work with what I have.

The water butt set up looks like a good thing from a gardening point of view and I would not suggest any physical changes.

If the butt has been full of water and it has frozen it will be pulling down the temperature in that area. What I would look into doing is draining down the butt between November and late March.

The empty butt with a lid on will heat up to a certain extent when it has the sun on it and may provide a warming roost for our feathered friend's. Always nice to see them about.

Good idea to drain the butt, it could certainly do with an interior clean.  But I don't know how I'd stop it from re-filling, I don't understand how the connector in the drain pipe works - presumably I'd have to disconnect one end of the flexible connecting pipe?  I have a very tall and steep pitch roof and that butt would fill very quickly in a decent shower as there's a lot of water passes down that pipe.

Sorry to sound so dense - every new job like this I tackle ends up being a steep learning curve.

I suspect the other changes you’re considering will make much more difference than draining the water butt.

QrizB

BooJewels said:

I don't understand how the connector in the drain pipe works - presumably I'd have to disconnect one end of the flexible connecting pipe?

If you disconnect the flexi pipe from the butt at the "butt" end, then lift it up so the "butt" end of the ppe is higher than the fitting on the downpipe, no water will flow from the flexi pipe and it will all go down the downpipe.

However, I also agree with bjorn:

bjorn_toby_wilde said:

I suspect the other changes you’re considering will make much more difference than draining the water butt.

Eldi_Dos

Do not know how those connections between down pipe and butt work, presumably when water gets to a certain height it flips something in the downpipe to redirect water.
Anyone think putting a cork in it would help?

QrizB

Eldi_Dos said:

Do not know how those connections between down pipe and butt work, presumably when water gets to a certain height it flips something in the downpipe to redirect water.

There are no moving parts.

There's a doughnut-shaped cup unside the downpipe. This catches some of the rainwater and diverts it ino the pipe and from there to the butt.

When the butt is full the water backs up along the pipe, the cup fills up and the water overflows back down the downpipe to the drain.

Here's a picture, if it helps:

Eldi_Dos

Ah, so a cork would work.

WIAWSNB

bjorn_toby_wilde said:

BooJewels said:

Eldi_Dos said:

BooJewels said:

Eldi_Dos said:

@BooJewels

Could the proximity of the water butt have any bearing?
If water butt has frozen it will act as a cold store helping to keep the condensate pipe cold enough for to cause the freezing.

I have no idea, they've always been in the same position.  You could also perhaps argue that the water butt keeps the worst of the wind off the pipe and provides some shelter.  I truly have no idea.  Neither can be moved, so I'll have to work with what I have.

The water butt set up looks like a good thing from a gardening point of view and I would not suggest any physical changes.

If the butt has been full of water and it has frozen it will be pulling down the temperature in that area. What I would look into doing is draining down the butt between November and late March.

The empty butt with a lid on will heat up to a certain extent when it has the sun on it and may provide a warming roost for our feathered friend's. Always nice to see them about.

Good idea to drain the butt, it could certainly do with an interior clean.  But I don't know how I'd stop it from re-filling, I don't understand how the connector in the drain pipe works - presumably I'd have to disconnect one end of the flexible connecting pipe?  I have a very tall and steep pitch roof and that butt would fill very quickly in a decent shower as there's a lot of water passes down that pipe.

Sorry to sound so dense - every new job like this I tackle ends up being a steep learning curve.

I suspect the other changes you’re considering will make much more difference than draining the water butt.

Yes. Leave yer butt alone. 

WIAWSNB

Eldi_Dos said:

Ah, so a cork would work.

Yes. Or just disconnect the flexi hose from the butt, and secure it higher than the DP connection.
But, really, just leave it.

BooJewels

Thanks for the details of how to stop the butt refilling - I thought that I knew how it worked, which you've confirmed, thank you.  I didn't know if there was anything cleverer to stop it refilling.  It has been there a long time, so I'm not sure the hose will come out cleanly - it's probably a bit brittle and may well shatter if I try to remove it.

I'm in 2 minds about draining it anyway - it could be that if it's freezing, it is impacting the condensate drain, but it could also be acting as a shelter/wind break too, as the pipe is nestled in behind it.  As already mentioned, there are other factors I'll address first and see what difference they make.

WIAWSNB

BooJewels said:

WIAWSNB said:

BooJewels said:

WIAWSNB said:

Blimey, yes, it's astonishing that it's freezing - it looks an ideal setup.
But, once it did freeze, then I think it's pretty clear it never got completely unfrozen again, so subsequent refreezes were much more likely.
So, why did it freeze first time? No idea! The pipe is a good size, so should drain instantly. I guess that a glaze could form on the inside of the pipe wall, and this just builds up with each glug.
Yes, condie is usually dispensed in glugs, I understand because it's via a 'syphon', a bit like a toilet cistern, so that there's always a water 'seal' that prevents combustion gases getting out.
Could there be other water coming out that way? Yes, if the Main Exchanger has failed and is leaking internally, but that would show as a very significant system pressure drop. You don't have this.
Also 'possible' that rain getting in the flue would end up in the combustion chamber and exit via the condie pipe. But unless you have a broken gutter cascading water down on your flue terminal, this is also unlikely.
So, I'd be looking at the bottom of the condensate pipe, and check that it's unrestricted - nowt in t'way.
Then I'd get good quality lagging, and slip a thin layer behind the pipe between it and the wall if theres only a tight gap, and clip the full sleeve over the rest. Almost certainly that's all you'll need. Complete overkill to go heating element in this case, imo.

I don't think there are any faults with the boiler, as everything else appears to be okay - no drop in pressure etc.  I'm wondering if it's occurring from the bottom - if you see later suggestions, as well as your own, maybe the ice is starting where the pipe touches the grate - maybe that is the cold spot that starts the process.  It wasn't blocked there when I first unblocked it yesterday morning - but there's a little angle connector at the bottom that directs the fluid over the centre of the grate, rather than towards the edge where the vertical of the pipe would land it - that was touching the ground, so is perhaps a cold connection. 

But the more I look at it, the more confused I'm getting.  

I agree - there's nothing else amiss with the boiler - you are simply having freezing condensate, and the addition of insulation will almost certainly sort it.
And I suspect it's as Plumb suggested - the issue literally begins at the bottom and builds up. Adding insulation to the pipe should mean that the lukewarm condie should now get to the bottom and prevent any freezing.
Really, nuts to do anything more than this in the first instance - get the good insulation jacket that folk have recommended, try and squish some in between the wall and pipe too, and forget about holes and heating elements.
But, yes, examine what's happening at the bottom of the pipe - consider removing the shoe provided it isn't needed, and ensure there's a gap between the pipe end and the surface below. 
But pretty sure insulation alone will do it - it should allow the condensate to remain well above freezing all the way down. 
You are right to not consider DIYing a condensate pipe alteration at the boiler, if you don't fully understand what's required. Just for info, it's typical that the first condensate pipe connection to the boiler is a snug push-fit and can be dismantled if wished, and subsequent pipe joints are solvented so fixed, but still best avoided - and just not needed. Q - is the boiler in a heated room like a kitchen? If not - say it's in an unheated utility room or garage - then add insulated sleeving to the internal condie pipe too.
And if you can take a pic of the bottom of the pipe in the gulley, it would be interesting. 

Evening, I've finally got chance to get back to this with a photo etc.

The boiler is in the utility room - which is unheated, but the doorway is immediately adjacent to a very large kitchen radiator and I wedge the door a foot open in winter, so some heat from the rad goes into the utility - so it's a cool room, rather than a cold one (15.3º C just now when I checked).  I don't think it's cool enough to chill the condensate in the interior pipes - in fact, that pipe feels slightly warm to the touch.  But if I end up with any offcuts, I will add them there too.

I must apologise to @Yorkie1 - I do have a flexible length of hose, the section that's currently tucked at the side of the boiler case is in fact flexible when I look at it more carefully.  The rigid piece it joins to would be tricky to disconnect - so it's a moot point anyway - but I just wanted to correct my earlier comment.

This is the bottom end of the pipe and guttering downspout above the grate - the elbow connector was originally attached to the end of the condensate pipe on the right - I think overhand, bending towards the grate.  I twisted it to the side on Monday morning to see if was blocked.  When I looked at it again yesterday it came away in my hand and was full of ice.  As it happens, I can't easily get it back on just now - so I intend to leave it off. 

I also found a short length (about 10") of grey insulation tubing around something larger, so it has stretched, so I will borrow that to put over the last section of the pipe nearest the ground until I can do the job properly.   I have some thin sheet foam too, which I can maybe wrap around it if that doesn't work. 

But hopefully, if it's off the ground and not in contact, it should be less likely to freeze - the condensate should just drip off the open end, fingers crossed.  I need to clean the area a bit better too - I've never got up all the leaves this year, as it has rained so much.  The drain cover has gone back over it again and I'll look at maybe adding some insulation to the underside of that too - need to dig out some materials.

Good job. That looks better. Insulated the length of the pipe.
I'd just monitor it now. Hopefully sorted, but easy to spot what the issue is if not.
Yes, if you have spare insulation, add it to the narrower condensate pipe inside, or but some cheap stuff from Screwfix. Anything to maintain the condie temp as much as possible.