Oxbow16 Posted December 31, 2020 Share Posted December 31, 2020 Seconds up - Round 2 of the wood burning stove questions from me... This time I'm curious as to what temperature the body of your stoves get to (anyone use a thermometer on the stove itself?). And/Or - if you've read the manual that came with it - what the manufacturer species as the maximum? The reason I ask is because we've narrowed our search down to the Woodwarm Fireview 5kW Slender. I was reading through the manual online and it says the maximum is 230C. That seems quite low to me. A quick glance at some of the stove thermometers out there and I see they show an optimum burn range. One has this at 150-300C, another at 200-350C. The Woodwarm made thermometer shows up to 300C as optimum! For the record, the manual I was reading refers to the whole range of Fireviews, which has models up to 20kW. So the 230C max. applies to them all. And the manual goes on to say "...avoid continuous running at the maximum..." Does anyone have any thoughts as to whether a maximum 230C body temperature is low and whether that will affect performance? I appreciate a lot goes into the design of wood stoves and there's a lot more to them than the statistics. And I've also read many glowing reports on Woodwarm; often mentioned in the same breath as Clearview. Nevertheless, this surprised me. Ta Link to comment Share on other sites More sharing options...
joe90 Posted December 31, 2020 Share Posted December 31, 2020 I don’t believe my stove gets anywhere near those temps, but in a well insulated house it does not run fir more than a couple of hours at a time. 1 Link to comment Share on other sites More sharing options...
ProDave Posted December 31, 2020 Share Posted December 31, 2020 There is a BIG difference between the burn temperature and the body temperature of a stove. If you want to measure the burn temperature the normal place for a thermometer is on the section of single wall flue immediately above the outlet. Even that will be lower than the actual burn temperature. Our stove is a convection stove so the sides don't get particularly hot at all. It has an extra "plate" fixed to each side and the back that encourages more heat to leave the stove by convection up the gap. It also means it has some increadably low "distance to combustible materials" figures compared to most. It is that distance to combustibles you need to note for your chosen stove to make sure you can comply with it's requirements. 1 Link to comment Share on other sites More sharing options...
Oxbow16 Posted December 31, 2020 Author Share Posted December 31, 2020 17 minutes ago, joe90 said: I don’t believe my stove gets anywhere near those temps, but in a well insulated house it does not run fir more than a couple of hours at a time. I wonder what temps you do get to? Have you ever tried a thermometer? Some stoves apparently get up to those temps well within the hour. And also, I've read time and time again how important it is to run stoves close to/at maximum to keep the glass clean and to burn all the crud out of the flue. Our house is old and not all that well insulated, so we'll be running the stove a bit more than that. However, we don't like a hot house and usually turn the heating off when it gets to 16C-17C. 9 minutes ago, ProDave said: There is a BIG difference between the burn temperature and the body temperature of a stove. If you want to measure the burn temperature the normal place for a thermometer is on the section of single wall flue immediately above the outlet. Even that will be lower than the actual burn temperature. Our stove is a convection stove so the sides don't get particularly hot at all. It has an extra "plate" fixed to each side and the back that encourages more heat to leave the stove by convection up the gap. It also means it has some increadably low "distance to combustible materials" figures compared to most. It is that distance to combustibles you need to note for your chosen stove to make sure you can comply with it's requirements. I'm not so worried about the burn temperature tbh - neither what it is nor measuring it. It was just the maximum stove body temperature of 230C that caught my eye... Cheers Link to comment Share on other sites More sharing options...
ProDave Posted December 31, 2020 Share Posted December 31, 2020 My flue thermometer suggests the flue temperature should be maintained between 150C and 250C. Any lower and the flue will tar up, any higher it just says "too hot" (chimney fire?) The actual burn temperature to achieve that will be hotter and I can't see the external body temperature matters, that depends so much on the construction of the stove. Link to comment Share on other sites More sharing options...
Ferdinand Posted December 31, 2020 Share Posted December 31, 2020 I am not clear what the "body temperature" is - is that the temperature of the metal body outside the firebrick liner? Or of the surface that your cat will only land on once? 230C is about the max temperature of most ovens, which probably does not help as a comparator. We did once crack the cast iron body of a wood stove, but that was (at least 3) decades ago and we were filling it with stacks of plywood offcuts. It is also less variation than the speedometer on cars of equal performance. Link to comment Share on other sites More sharing options...
PeterW Posted December 31, 2020 Share Posted December 31, 2020 32 minutes ago, Oxbow16 said: It was just the maximum stove body temperature of 230C that caught my eye... It will be lined with vermiculite panels which absorb the heat and insulate the firebox to keep burn temps and flue temps high. 230°C max sounds about right. Link to comment Share on other sites More sharing options...
bassanclan Posted December 31, 2020 Share Posted December 31, 2020 Link to comment Share on other sites More sharing options...
bassanclan Posted December 31, 2020 Share Posted December 31, 2020 Link to comment Share on other sites More sharing options...
Oxbow16 Posted December 31, 2020 Author Share Posted December 31, 2020 1 hour ago, Ferdinand said: I am not clear what the "body temperature" is - is that the temperature of the metal body outside the firebrick liner? Or of the surface that your cat will only land on once? Perhaps I'm not using the correct time, but I'm referring to the outside body of the stove. A lot of people seem to put their stove thermometers above the door, and I have seen this recommended too. I have also seen it on the sides and tops of stoves. 1 hour ago, Ferdinand said: 230C is about the max temperature of most ovens, which probably does not help as a comparator. As the Clearview Pioneer was on our shortlist I took a look at that. From what i could find they say they try to run the stove between 204C and 288C. And that above 340C could cause damage. Out of curiosity I also took a look at the Country 4 manual and it only mentions flue temperature, not stove body temperature. But there is an entry on WhatStove where a user says that at 450C (!!!) they can't open the door! The "stove expert" replies that "450 degrees C is on the top limit of operating recommendations". And as mentioned above, stove thermometers seem to regard up to 300C as optimum. 1 hour ago, PeterW said: It will be lined with vermiculite panels which absorb the heat and insulate the firebox to keep burn temps and flue temps high. 230°C max sounds about right. I must admit to being quite confused by burn temps vs stove body temps. If the stove is designed to always have the door closed - as most are - then why is the internal temperature relevant? The heat has to transfer into the room, and does this not happen through the heat up of the stove body? In which case would that not be more important and relevant (putting stoves with convection panels to the side for the moment)? @bassanclan - that looks lovely and cosy Perfect for a snowy day here in Wales. I can't quite make out the temps on the thermometer though... What do they read? I'd also be interested to hear how high it gets when you have the stove running at it's hottest. Ultimately, if the Woodwarm stove performs and keeps us warm, and does so as well as its competitors, then I don't care what the maximum stove body figure is. But whilst I'm no physics expert, common sense makes me think that the hotter the stove is the more heat it will give off. Many thanks for all the replies and for sharing your thoughts Link to comment Share on other sites More sharing options...
jamieled Posted December 31, 2020 Share Posted December 31, 2020 30 minutes ago, Oxbow16 said: If the stove is designed to always have the door closed - as most are - then why is the internal temperature relevant? Because there is a big drive to reduce emissions from wood burning. One of the ways to do that is by ensuring the fire chamber is at the correct temperature. Link to comment Share on other sites More sharing options...
Oxbow16 Posted December 31, 2020 Author Share Posted December 31, 2020 1 hour ago, jamieled said: Because there is a big drive to reduce emissions from wood burning. One of the ways to do that is by ensuring the fire chamber is at the correct temperature. Yeah, I can see that. And the flue performs better when at the correct heat as well. Points taken. But I'd still think the stove body temperature has a direct bearing on how much heat the stove is giving to the room. Unless I'm missing something. Link to comment Share on other sites More sharing options...
ProDave Posted December 31, 2020 Share Posted December 31, 2020 1 minute ago, Oxbow16 said: Yeah, I can see that. And the flue performs better when at the correct heat as well. Points taken. But I'd still think the stove body temperature has a direct bearing on how much heat the stove is giving to the room. Unless I'm missing something. Yes and no. My stove is only rated at 5kW but is physically quite large for a 5kW stove, so it stands to reason that for a large stove to only emit 5kW it's external temperature must be lower. We ended up with the stove we have because I took SWMBO to look at them. I was thinking of the little 3kW springdale, but SWMBO looked at it and decided it looked ridiculously small. So we set off around all the shops to see what was available and bought what is probably physically largest 5kW stove made. Link to comment Share on other sites More sharing options...
Oxbow16 Posted December 31, 2020 Author Share Posted December 31, 2020 I have been thinking about how stove size must play a part. But the Pioneer 400, all in all, is a similar size to the Fireview 5kW. They are both 5kW. The Clearview's range is 1-5kW; not sure what the range for the Woodwarm is as they don't specify but I'd hazard a guess it's more. Yet in spite of being the same in all these respects, the body of the Clearview is capable of reaching a much higher maximum (340C vs 230C). Also, if we compare the dimensions of the 5kW with the 20kW, the latter ain't 4 times bigger: 05kW: Height: 605mm / Width: 505mm / Depth: 302mm 20kW: Height: 735mm / Width: 770mm / Depth: 486mm If you don't mind me asking, which stove do you have? Link to comment Share on other sites More sharing options...
PeterW Posted December 31, 2020 Share Posted December 31, 2020 There is no easy correlation between stove size and heat output. Look up the 5kw Hwam stoves, they are very big but small output. This Hwam Beethoven with a soapstone surround is only 4.5kw for example. At over 1050mm tall, it looks big but isn’t ..! Link to comment Share on other sites More sharing options...
ProDave Posted December 31, 2020 Share Posted December 31, 2020 Mine is a Mendip stoves Churchill 5, log store convection model. We wanted a small stove that must have ducted air intake, and must look modern. We bought this as an ex display model on sale. That was with a temporary hearth and a temporary (illegally overhanging) kitchen worktop. Here is the final worktop and hearth before the stove was put back Link to comment Share on other sites More sharing options...
bassanclan Posted December 31, 2020 Share Posted December 31, 2020 The photo is of a Clearview stove. I think pioneer 500. The optimum burn on that thermometer is 140-300c approx. It generally sits around 150-200, but can get to 300c if you really load it and burn it hard. I have a Dunsley Yorkshire with back boiler and it's not as easy to light or control and doesn't keep as clear a screen as the Clearview,but does run at similar temps. Link to comment Share on other sites More sharing options...
TonyT Posted January 1, 2021 Share Posted January 1, 2021 Wow. Same question asked in the navitron forum yesterday morning! Link to comment Share on other sites More sharing options...
ProDave Posted January 1, 2021 Share Posted January 1, 2021 You wanted figures, so when our stove was on last night I got the IR thermometer out. Flue temp 200C Glass temp, 250C Stove top 75C Stove sides 65C stove back 50C Inside the firebox with the door open >500C didn't hang about there not sure if that might have been a bit hot for the IR thermometer. Link to comment Share on other sites More sharing options...
Oxbow16 Posted January 3, 2021 Author Share Posted January 3, 2021 Hi all Big thanks for all the responses, shared photos, and @ProDave for taking those readings. Much appreciated. The body temperature readings you got are much lower than I'd have expected for a stove. Not really different to many radiators. And I guess you wouldn't be boiling a kettle on the stove top then, like many folk do? How hot was the room with the stove running at that temp, and was it the only form of heating? On 01/01/2021 at 00:28, TonyT said: Wow. Same question asked in the navitron forum yesterday morning! Of all the things in the world to "WOW" at, I'm surprised that's one of them! Is there a problem with that? I think there's more of a "WOW" factor in you taking the time to make that your only contribution to the thread. Link to comment Share on other sites More sharing options...
ProDave Posted January 3, 2021 Share Posted January 3, 2021 13 minutes ago, Oxbow16 said: Hi all Big thanks for all the responses, shared photos, and @ProDave for taking those readings. Much appreciated. The body temperature readings you got are much lower than I'd have expected for a stove. Not really different to many radiators. And I guess you wouldn't be boiling a kettle on the stove top then, like many folk do? How hot was the room with the stove running at that temp, and was it the only form of heating? Yes my stove is different to most, it's a convection model which means it has extra plate hung on the sides back and top with a small air gap to the main body of the stove. This reduces radiant heat and gives more convected heat instead, as you say a bit more like a radiator. Room was about 24 degrees. The stove is not our main source of heat, that is UFH with the thermostats set to 20 degrees. The stove is when we want to indulge and roast ourselves, but being mostly our own wood, at zero cost. Though at 5kW the stove would heat the whole house if you wanted it to. We have to keep the room doors open when the stove is on to let the heat into the whole downstairs and up the stairwell to upstairs. Shut the doors and you would very quickly overheat the room the stove is in. The original plan had another stove in the snug living room, we quickly dropped that off the plans as the room would have been too small for it. Link to comment Share on other sites More sharing options...
Oxbow16 Posted January 3, 2021 Author Share Posted January 3, 2021 Ah, yes - of course. Sorry, you had said it was a convection stove and I just wasn't thinking Great to hear it heats a lot of your house. Although our house will have a heck of a lot less insulation than I imagine yours does, we tend to suffocate when it gets to +17C. So I'm holding out hope that our stove heat will reach afar. If you don't mind me asking, how big is the kitchen? Many thanks Link to comment Share on other sites More sharing options...
ProDave Posted January 3, 2021 Share Posted January 3, 2021 Kitchen is just a little over 7M by 5M. Link to comment Share on other sites More sharing options...
Oxbow16 Posted January 3, 2021 Author Share Posted January 3, 2021 Ah, so not a small room by any means. Our living room - which will have the wood burner - is 4.5m x 4.5m, so a fair bit smaller. It has an open stairwell in the room. There's also two internal doors, one of which will usually be closed (goes to a lobby / hall), but one of which is always open and leads to a kitchen (4.5m x 3.5m), which is semi open-plan to a dining room (3.5m x 3.5m). We're hoping to get some heat around the rest of those rooms; more so in the kitchen and dining room, less so upstairs as we prefer a cold bedroom. A 5kW is the largest we can fit physically into our fireplace, so we won't be going any larger. There's nothing we can do to close off the stairwell, so it really is a case of what will be will be. Except perhaps the use of fans to move the heat around. Just really hoping the kitchen and dining room will benefit a bit from the heat. Thanks again Link to comment Share on other sites More sharing options...
Oxbow16 Posted January 20, 2021 Author Share Posted January 20, 2021 Hi all Just thought I'd revisit this as I can't stop mulling it over to try to make sense of it! A couple of things... I noticed yesterday that the Woodwarm Foxfire (4kW) has a maximum stove body temperature of 350C. 120C more than the Fireview. They both have a similar internal layout, are both steel and both have 30mm mica based fire boards. So that's got me scratching my head! Since learning more about all this, I can now see how the glass plays a part in the heat output, and how the internal heat is relevant to many things (burning of secondary gases, flue temps, emissions, etc). But it still seems logical to me that the temperature of the stove body will have a direct bearing on the amount of heat that can radiate out into the room. And as such, I can't understand how a stove that's only a bit bigger physically can quadruple the kW output. Unless it's logarithmic... ??? Americans tend to like to do things on a grander scale (no offence to any Americans reading, and I mean it as a sweeping statement). Having read a fair few threads on the net discussing stove temps, some of the more cavalier wood burning folk discussing running their stoves to a body temp of over 1,000F. I've even seen 1,200F mentioned (that's 650C in our money)! Whilst that sounds like a serious recipe for disaster and I have no aspirations to burn my house down, it did on the other hand make 230C maximum seem a touch puny. Cheers Link to comment Share on other sites More sharing options...
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