soapstar Posted January 25, 2021 Share Posted January 25, 2021 Hi Folks, Recently had our wood burning stove installed (all above board) by a qualified stove fitter and noticed the other day we have moisture on the top of the stove, didn't think much of it as we have hardly used it (maybe twice before this) and thought perhaps its condensation etc. However yesterday we now have a little pool of water sitting on top of the stove (picture attached), strange thing is we haven't had rain for a few days - only frost. Twin wall flue with cowl on top etc What on earth could cause this to happen?! ? Link to comment Share on other sites More sharing options...
ProDave Posted January 25, 2021 Share Posted January 25, 2021 It will be condensation running down the inside of the pipe. Get your installer back, one of the joints is not right. 1 Link to comment Share on other sites More sharing options...
soapstar Posted January 25, 2021 Author Share Posted January 25, 2021 Just now, ProDave said: It will be condensation running down the inside of the pipe. Get your installer back, one of the joints is not right. thanks @ProDave I assume this would mean if water is getting out then smoke/gas will almost certainly get into the room? Link to comment Share on other sites More sharing options...
Carrerahill Posted January 25, 2021 Share Posted January 25, 2021 4 minutes ago, soapstar said: Hi Folks, Recently had our wood burning stove installed (all above board) by a qualified stove fitter and noticed the other day we have moisture on the top of the stove, didn't think much of it as we have hardly used it (maybe twice before this) and thought perhaps its condensation etc. However yesterday we now have a little pool of water sitting on top of the stove (picture attached), strange thing is we haven't had rain for a few days - only frost. Twin wall flue with cowl on top etc What on earth could cause this to happen?! ? What are you burning? This is a problem I have seen with stoves with back boilers running cool with wet wood - the walls of the firebox and flue never get that hot, the result is all the steam from the wood condensates on the cool surfaces and runs down the stove wall, I was once met with a stream of black water running out a stove door at a friends farmhouse when he was using a lot of damp wood. I have also seen black streaks running out of flue/chimney connections where the same is happening in the flue. If you are burning the sort of fuel you ought to be you shouldn't have an issue. On first ignition a little moisture will be seen on metal and glass surfaces inside the firebox, that is even with bone dry kindling, however the temp will come up and soon disappear as the temp comes up. I might be way off the mark, but did you burn a lot of damp or wet wood and perhaps not let it rip properly? This can also be caused if you have too high an output stove in too small a room, people then try and underrun them and the never get up to temp, killing the stove and flue early as the gasses are always a bit damp. The next point is that the flue should be constructed in such a way that the higher part always sleeves into the lower, this is to stop moisture or rain managing to run down and escape from the flue, except from into the stove itself. 1 Link to comment Share on other sites More sharing options...
soapstar Posted January 25, 2021 Author Share Posted January 25, 2021 1 minute ago, Carrerahill said: What are you burning? This is a problem I have seen with stoves with back boilers running cool with wet wood - the walls of the firebox and flue never get that hot, the result is all the steam from the wood condensates on the cool surfaces and runs down the stove wall, I was once met with a stream of black water running out a stove door at a friends farmhouse when he was using a lot of damp wood. I have also seen black streaks running out of flue/chimney connections where the same is happening in the flue. If you are burning the sort of fuel you ought to be you shouldn't have an issue. On first ignition a little moisture will be seen on metal and glass surfaces inside the firebox, that is even with bone dry kindling, however the temp will come up and soon disappear as the temp comes up. I might be way off the mark, but did you burn a lot of damp or wet wood and perhaps not let it rip properly? This can also be caused if you have too high an output stove in too small a room, people then try and underrun them and the never get up to temp, killing the stove and flue early as the gasses are always a bit damp. The next point is that the flue should be constructed in such a way that the higher part always sleeves into the lower, this is to stop moisture or rain managing to run down and escape from the flue, except from into the stove itself. Hi @Carrerahill That does make sense what you are saying about damp wood. We aren't in our house yet so have been trying to burn off the 'new smell' you get from a new stove with only logs, no other fuel. This wood should be very dry, I wouldn't say its 100% dry but it was cut 2 years ago and left to dry under cover. The only thing perhaps is because we haven't got the stove up to max temperature yet? We just light it with a couple sticks now and then, given we aren't living there we don't want to be waiting for hours until it goes out! Thing is this water doesnt appear the day after we light it the stove, its more like a few days or even over a week. We do not have any moisture or wetness inside the actual stove, only on the top. The stove is only a 4.1kw so not massive. Link to comment Share on other sites More sharing options...
Carrerahill Posted January 25, 2021 Share Posted January 25, 2021 (edited) 28 minutes ago, soapstar said: thanks @ProDave I assume this would mean if water is getting out then smoke/gas will almost certainly get into the room? No, assuming your flue was checked and the draught is correct it will be under vacuum. There was an article in the Guardian recently, it was research on particulate coming into the room on refuelling stoves, a big scare narrative claiming when you open the door all this pollutions zooms into the room. Tripe, utter tripe, I wrote to them called the whole article into contention, in a long, technically based email the environmental editor was really unable to come back to me with anything to refute my claims. Basically the research had been created to tell a particular story. The first thing any stove installer, be it DIY or pro, should do it confirm suitability of the existing chimney for lining, or the siting of a new flue for draught. Small cottages with a short chimney are sometimes problematic, sometimes the problem goes once it is warmed up and the fire going well creating more of a draw with the heat convection. So, with that in mind, with a properly installed stove, while the stove is running, you could drill a hole in the flue and smoke would not come out. This was also my argument for the pollution coming into the room. Yes on a poorly installed stove with a poor flue draught it is possible smoke, i.e. pollution may come into the room but I know for near certainty in my stove it is not. Another reader of the Guardian also wrote in commenting that he bought a pollution meter, set it up and monitored pollution in a room with a stove, he actually thought his meter wasn't working and tested it by lighting a match in the room where the meter recorded a spike in particulate, his stove clearly was properly installed and the draught up the flue was such that when the door is open it is sucking like a room vacuum, nothing is coming out. If you were to fling the door open at 200mph then yes, a sudden turbulence created by the door swinging open and the suction created would draw some smoke into the room but nothing serious. Edited January 25, 2021 by Carrerahill Link to comment Share on other sites More sharing options...
Carrerahill Posted January 25, 2021 Share Posted January 25, 2021 1 minute ago, soapstar said: Hi @Carrerahill That does make sense what you are saying about damp wood. We aren't in our house yet so have been trying to burn off the 'new smell' you get from a new stove with only logs, no other fuel. This wood should be very dry, I wouldn't say its 100% dry but it was cut 2 years ago and left to dry under cover. The only thing perhaps is because we haven't got the stove up to max temperature yet? We just light it with a couple sticks now and then, given we aren't living there we don't want to be waiting for hours until it goes out! Thing is this water doesn't appear the day after we light it the stove, its more like a few days or even over a week. We do not have any moisture or wetness inside the actual stove, only on the top. The stove is only a 4.1kw so not massive. Most stoves say after a couple of small burn in fires you should take it up to max temp to burn the paint smell off, what does your stove say, my experience is that you need to fire them up HOT very hot (within working spec obviously) with all the windows open and get the paint smell burn off, but maybe your stove calls for a different procedure? The 2-3day pause is perplexing then. You sure it is not rain related? What is the situation with the terminal at roof level? Pokey hat with a grate round it? I'd get it all fired up to full temp and see what happens 2-3 days later. Link to comment Share on other sites More sharing options...
TonyT Posted January 25, 2021 Share Posted January 25, 2021 If you have a flexi liner, hope it’s installed the right way and the pipe isn’t upside down Link to comment Share on other sites More sharing options...
ProDave Posted January 25, 2021 Share Posted January 25, 2021 26 minutes ago, Carrerahill said: The next point is that the flue should be constructed in such a way that the higher part always sleeves into the lower, this is to stop moisture or rain managing to run down and escape from the flue, except from into the stove itself. I would say this is the bit that has been done wrong at the bottom joint from flue to stove hence the water is getting out of the flue. Link to comment Share on other sites More sharing options...
soapstar Posted January 25, 2021 Author Share Posted January 25, 2021 The last time we had rain was at least 3/4 days before this and we last had the stove lit around 1 week ago. The flue pipe goes through a rubber seal at roof level. @TonyT far as im aware its just solid twin wall flue pipe sections straight up Either way I will get the installer back out, I just wanted some advice encase I get told some BS Link to comment Share on other sites More sharing options...
PeterW Posted January 25, 2021 Share Posted January 25, 2021 This is twin wall isn’t it ..? Is the liquid clear and does it have any smell at all..?? Points to a potential issue where the cap of the flue may not have been installed correctly and the insulation layer is getting wet or has previously got wet and frozen / thawed and this is running down the inside of the insulation jacket. It would be very unlikely that this is flue leakage and more likely outer skin leakage if the liquid is clean looking. 1 Link to comment Share on other sites More sharing options...
soapstar Posted January 25, 2021 Author Share Posted January 25, 2021 Just now, ProDave said: I would sat this is the bit that has been done wrong at the bottom joint from flue to stove hence the water is getting out of the flue. Sorry I am confused with this bit, do you mean the flue diameter shouldn't reduce before the stove? Link to comment Share on other sites More sharing options...
soapstar Posted January 25, 2021 Author Share Posted January 25, 2021 (edited) 5 minutes ago, PeterW said: This is twin wall isn’t it ..? Is the liquid clear and does it have any smell at all..?? Points to a potential issue where the cap of the flue may not have been installed correctly and the insulation layer is getting wet or has previously got wet and frozen / thawed and this is running down the inside of the insulation jacket. It would be very unlikely that this is flue leakage and more likely outer skin leakage if the liquid is clean looking. Yes twin wall. At first the liquid was quite oily/watery to touch, when hot it stained the stove white. Now this time it seems to be just water, there is no oily consistency to it now. It certainly isnt black or sooty coloured Your theory seems the most likely actually. It would make sense as there is no wetness inside the stove. What exactly is inside the insulated part of the flue, would the water be absorbed into anything? Hence the time it takes to reach the bottom of the flue? Edited January 25, 2021 by soapstar Link to comment Share on other sites More sharing options...
PeterW Posted January 25, 2021 Share Posted January 25, 2021 Ok so oily would be the coating off the stainless potentially. What is the cap at the top of the flue ..? Got any photos ..?? Link to comment Share on other sites More sharing options...
soapstar Posted January 25, 2021 Author Share Posted January 25, 2021 Sorry I have just realised I have no close up photos of the external flue! Link to comment Share on other sites More sharing options...
PeterW Posted January 25, 2021 Share Posted January 25, 2021 Doesn’t look straight from there so cap could be leaking. Link to comment Share on other sites More sharing options...
soapstar Posted January 25, 2021 Author Share Posted January 25, 2021 3 minutes ago, PeterW said: Doesn’t look straight from there so cap could be leaking. I was thinking that myself ? Link to comment Share on other sites More sharing options...
PeterW Posted January 25, 2021 Share Posted January 25, 2021 That’s a cherry picker job by the looks of it. Wonder if the locking band hasn’t been done up properly...?? Link to comment Share on other sites More sharing options...
soapstar Posted January 25, 2021 Author Share Posted January 25, 2021 2 hours ago, PeterW said: That’s a cherry picker job by the looks of it. Wonder if the locking band hasn’t been done up properly...?? I will have to investigate later on, looks very suspect! Thanks Link to comment Share on other sites More sharing options...
soapstar Posted February 15, 2021 Author Share Posted February 15, 2021 To anyone interested down the line it was actually the cap that was leaking, it was changed out for a different style and this has fixed the issue! Yay on to the next issues! 2 Link to comment Share on other sites More sharing options...
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